Found this article...
"Single-phase induction motors drive many arbor-mounted cutting tools in the
home workshop. Stationary grinders, table and radial arm circular saws
frequently turn abrasive or cutting disks that are directly mounted on the
motor's spindle. These disks have large inertial moments that allow them to
free wheel for a long time after the power is turned off. A lengthy coast to
complete stop often amounts to a major inconvenience."
http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
On Sun, 10 Oct 2010 17:30:01 -0500, -MIKE- <[email protected]>
wrote:
>On 10/10/10 4:51 PM, Larry Jaques wrote:
>> On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE-<[email protected]>
>> wrote:
>>
>>> On 10/10/10 11:35 AM, willshak wrote:
>>>> WW wrote the following:
>>>>> "HeyBub"<[email protected]> wrote in message
>>>>> news:[email protected]...
>>>>>> Found this article...
>>>>>>
>>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>>>> in the home workshop. Stationary grinders, table and radial arm
>>>>>> circular saws frequently turn abrasive or cutting disks that are
>>>>>> directly mounted on the motor's spindle. These disks have large
>>>>>> inertial moments that allow them to free wheel for a long time after
>>>>>> the power is turned off. A lengthy coast to complete stop often
>>>>>> amounts to a major inconvenience."
>>>>>>
>>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>>>
>>>>>>
>>>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>>>> brake. WW
>>>>
>>>> If I need to stop a spinning table saw blade in a hurry to change or
>>>> reset something, I find that a scrap piece of lumber makes a great blade
>>>> brake. Turn the saw off and slide the scrap up to the still spinning
>>>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>>>
>>>
>>> Someone could make some money by developing an aftermarket saw brake,
>>> under the table.... pads or rollers or whatever, that would squeeze the
>>> blade.
>>
>> Lawsuits from the arse with the SawStop patents notwithstanding, I
>> think he went with the positive stop style because it's the only one
>> which would keep from taking a finger off. The rest spin just enough
>> to do serious damage.
>>
>
>A saw blade brake wouldn't infringe on SawStop's patent at all.
WTF does that have to do with lawsuits? People sue to keep their
product on top whether they have a case or not. REAL WORLD, Mike.
--
Ask not what the world needs. Ask what makes you come
alive... then go do it. Because what the world needs
is people who have come alive. -- Howard Thurman
Steve Turner wrote:
>
> Another reality check for all the people taking this thread off into
> the wild blue yonder is the issue of getting the blade onto the arbor
> in the presence of calipers that grip either side of the blade. My
> interest (and Mike's as well, I think) in using a bicycle brake was
> simply a matter of "how can I retrofit my existing table saw with a
> simple convenience brake?" I think the wide-opening jaws of a
> bicycle brake (maybe along with some kind of front-side cable
> disconnect to allow the calipers to drop out of the way) would allow
> enough clearance to get the blade on the arbor without too much
> trouble. This heavy-duty automotive caliber Saw-Stop alternative
> that everybody else is talking about would also have to provide a
> similar mechanism, which would of course add to the complexity.
It would be quite easy to mount the caliper on a pivoting mount that would
allow it to swing out of the way for changing blades.
--
-Mike-
[email protected]
On Oct 14, 12:47=A0pm, -MIKE- <[email protected]> wrote:
> On 10/14/10 11:27 AM, Steve Turner wrote:
>
>
>
>
>
> > On 10/14/2010 11:15 AM, -MIKE- wrote:
> >> On 10/14/10 6:39 AM, Steve Turner wrote:
> >>> Another reality check for all the people taking this thread off into =
the
> >>> wild blue yonder is the issue of getting the blade onto the arbor in =
the
> >>> presence of calipers that grip either side of the blade. My interest
> >>> (and Mike's as well, I think) in using a bicycle brake was simply a
> >>> matter of "how can I retrofit my existing table saw with a simple
> >>> convenience brake?" I think the wide-opening jaws of a bicycle brake
> >>> (maybe along with some kind of front-side cable disconnect to allow t=
he
> >>> calipers to drop out of the way) would allow enough clearance to get =
the
> >>> blade on the arbor without too much trouble.
>
> >> Heck, I think if it was mounted closer to the arbor than the edge, one
> >> pad on
> >> the arbor side of the blade would be sufficient for a convenience
> >> slow/stop.
>
> > That very well could be true, and you could also use such a brake with
> > dado blades of any thickness... Interesting observation there Mike; I'm
> > gonna have to go do some peeking inside my Unisaw to see what the
> > possibilities are. :-)
>
> Good. =A0It's about time that happens to someone *else.*
> Let me know what you come up with so I can take credit for it. =A0 =A0 :-=
)
>
> --
>
> =A0 -MIKE-
>
> =A0 "Playing is not something I do at night, it's my function in life"
> =A0 =A0 =A0--Elvin Jones =A0(1927-2004)
> =A0 --
> =A0http://mikedrums.com
> =A0 [email protected]
> =A0 ---remove "DOT" ^^^^ to reply
Oh the mootness. (NOT aimed at anybody in particular)
Any disc or drum of any size will interfere with the raising of the
blade to the point that the disk brake hits the bottom of the table
somewhere.
I propose an air bag. Electronically triggered, it throws you
backwards across the shop and away from the table saw. Punches you
right in the chest with the option for a double bag for some people
here in which case the second bag knocks some sense in them. We can
glue on a boxing glove for that operation...just a 4 oz. one; you want
it to hurt a little.
One can mount the boxing glove on an expanding multi-pivot articulated
parallelogram.
What a stellar idea.
I'm talking to investors now.
They want to call the company ACME.
On Oct 10, 10:27=A0pm, -MIKE- <[email protected]> wrote:
"electromagnet/solenoid would do the trick"
My God man, you've invented the Saw Stop!
"HeyBub" <[email protected]> wrote in message
news:[email protected]...
> Found this article...
>
> "Single-phase induction motors drive many arbor-mounted cutting tools in
> the home workshop. Stationary grinders, table and radial arm circular saws
> frequently turn abrasive or cutting disks that are directly mounted on the
> motor's spindle. These disks have large inertial moments that allow them
> to free wheel for a long time after the power is turned off. A lengthy
> coast to complete stop often amounts to a major inconvenience."
>
> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>
Why did you find it???????????????
Steve Turner <[email protected]> wrote in
news:[email protected]:
*snip*
> Of course, right there in the description they're calling it a push
> "stick", which I think is erroneous. When I hear "push stick", I
> think of one of these pieces of crap:
>
> http://woodzone.com/Merchant2/graphics/00000001/push-stick.jpg
>
> which I would *never* use; they give me the willies. For plywood,
> it's entirely plausible to use a "push block"
>
*snip*
Trust your feelings, Steve.
I used that style of push stick for years, until I was cutting a small
piece and pressure on only the one point caused the piece to move and
catch on the back of the blade. The resulting kickback hit me in the
dust mask and broke the push stick. I will not use that style again.
Puckdropper
--
Never teach your apprentice everything you know.
In article <[email protected]>,
HeyBub <[email protected]> wrote:
> I was looking for a home remedy for a festering, fulminating, giant red
> mass on my, er, never mind.
A boil on the bum then :-)
On Oct 12, 12:21=A0pm, Steve Turner <[email protected]>
wrote:
wildly advancing your fingers towards the blade,
As is done when, say, you are pushing a bit of wood into the saw and
it jerks out of place and you essentially "fall" forward now that the
wood is no longer offering resistance?
Of course, the blade never stop turning at all on the saw I was using,
but I did manage to put three finges and a thumb in its path before
realizing I was cutting skin and bone - and jerked back.
Only cut clean through one digit and got it sewed and screwed back
on.
EXT wrote:
> "HeyBub" <[email protected]> wrote in message
> news:[email protected]...
>> Found this article...
>>
>> "Single-phase induction motors drive many arbor-mounted cutting
>> tools in the home workshop. Stationary grinders, table and radial
>> arm circular saws frequently turn abrasive or cutting disks that are
>> directly mounted on the motor's spindle. These disks have large
>> inertial moments that allow them to free wheel for a long time after
>> the power is turned off. A lengthy coast to complete stop often
>> amounts to a major inconvenience."
>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>
> Why did you find it???????????????
I was looking for a home remedy for a festering, fulminating, giant red mass
on my, er, never mind. Just say I stumbled across it and thought it might be
interesting to some (the motor business, not my, um, temporary disability).
-MIKE- wrote:
> On 10/11/10 7:11 AM, HeyBub wrote:
>> -MIKE- wrote:
>>
>>>
>>> I would prefer powered off/normal on, because the operator would get
>>> used to the blade always braking and in the case of a solenoid
>>> failure, the blade would not coast.
>>>
>>> I would also think an assembly with wheels applying just a little
>>> pressure to the sides of the blade would make a decent passive
>>> system. It would be just enough pressure to slow down the blade in
>>> a second or two and not enough pressure for the motor to even
>>> register the resistance.
>>> Think about how little pressure it takes with a scrap piece of wood
>>> to stop a coasting blade.
>>
>> Isn't there an old Indian trick about a spinning piece of wood and
>> starting a fire?
>>
>
> Point?
Everybody knows that, which is why I'm trying to explain. But everyone's
alive except those who drowned in an adjacent bog.
I know of a fellow that worked on a vertical sliding saw professionally and
stopped it with the side of his thumb, for years. One day he got a carbide
blade installed and forgot.
The fire was in the last half of his thumb.
Watch your working habits. Environments change. You may too... in body
shape.
"HeyBub" <[email protected]> wrote in message Isn't there an old Indian
trick about a spinning piece of wood and starting
a fire?
news:[email protected]...
-MIKE- wrote:
>
> I would prefer powered off/normal on, because the operator would get
> used to the blade always braking and in the case of a solenoid
> failure, the blade would not coast.
>
> I would also think an assembly with wheels applying just a little
> pressure to the sides of the blade would make a decent passive system.
> It would be just enough pressure to slow down the blade in a second or
> two and not enough pressure for the motor to even register the
> resistance.
> Think about how little pressure it takes with a scrap piece of wood to
> stop a coasting blade.
"HeyBub" <[email protected]> wrote in message
news:[email protected]...
> Found this article...
>
> "Single-phase induction motors drive many arbor-mounted cutting tools in
> the home workshop. Stationary grinders, table and radial arm circular saws
> frequently turn abrasive or cutting disks that are directly mounted on the
> motor's spindle. These disks have large inertial moments that allow them
> to free wheel for a long time after the power is turned off. A lengthy
> coast to complete stop often amounts to a major inconvenience."
>
> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>
>
>Great ... I may rig up my table saw this way. Would be safer with a brake.
>WW
LOL..I guess I am in the same boat as you. I did jump in late and saw (pun)
some twist about emerg. stopping the blade. Then I jumped in to point out a
difference in technique would be needed and got some resistance. Now I am
chatting with you and who knows whwre it went.
I am not disputing the effectiveness of the SawStop, at all. After seeing
videos I feel I owe the guy something without buying one. Amazing design.
Now I want to kno how to beat it with my wallet.
BTW: never owned a table saw and have never intended to. I know too many
that have lost an eye, fingers, thumb pieces and a **dog to one. When I wave
to somebody I don't want them to think I am giving them the one finger
salute.
**(j/k about the dog...LOL)
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
I guess I don't know what we're debating, anymore.
I thought we were talking about slowing down the coast of a saw blade
after turning off the power. I guess we got on a tangent.
If it's you're mission to dream up ways to refute the effectiveness of
the SawStop technology... well, I'm off the boat, because you've lost
your mind. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
Spoken like a true woodworker...LOL
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
C-clamp.
In article <[email protected]>,
[email protected] says...
>
> On 10/13/2010 02:32 PM, J. Clarke wrote:
> > In article<[email protected]>,
> > [email protected] says...
> >>
> >> On 10/13/10 9:43 AM, J. Clarke wrote:
> >>> In article<[email protected]>, [email protected] says...
> >>>>
> >>>> J. Clarke wrote:
> >>>>> In article<[email protected]>, [email protected] says...
> >>>>>>
> >>>>>> J. Clarke wrote:
> >>>>>>> In article<[email protected]>,
> >>>>>>> [email protected] says...
> >>>>>>>>
> >>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]>
> >>>>>>>> wrote:
> >>>>>>>>
> >>>>>>>>> J. Clarke wrote:
> >>>>>>>>>> In article<[email protected]>, [email protected]
> >>>>>>>>>> says...
> >>>>>>>>>>>
> >>>>>>>>>>> I would think that an emergency stop mechanism would be a
> >>>>>>>>>>> whole different
> >>>>>>>>>>> magnitude than a scheduled, everyday, stop.
> >>>>>>>>>>>
> >>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
> >>>>>>>>>>> stop the blade
> >>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
> >>>>>>>>>>> blade rotations
> >>>>>>>>>>> would be OK too. These two situations would require different
> >>>>>>>>>>> tactics.
> >>>>>>>>>>>
> >>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
> >>>>>>>>>>> two different
> >>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
> >>>>>>>>>>> caliper probably
> >>>>>>>>>>> wouldn't last long in everyday usage and would need to be
> >>>>>>>>>>> adjusted and/or
> >>>>>>>>>>> replaced frequently.
> >>>>>>>>>>
> >>>>>>>>>> So how much power do you have to put into that electronic brake
> >>>>>>>>>> to stop
> >>>>>>>>>> the blade as fast as Sawstop's physical block?
> >>>>>>>>>>
> >>>>>>>>>> And why would a caliper not last long? A set of brake pads on
> >>>>>>>>>> a car
> >>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a
> >>>>>>>>>> Hell of
> >>>>>>>>>> a lot more of a workout that they would stopping a little bitty
> >>>>>>>>>> saw
> >>>>>>>>>> blade that masses less than 1/1000 as much.
> >>>>>>>>>
> >>>>>>>>> The physics on that seem interesting. A little like stopping a
> >>>>>>>>> speeding
> >>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
> >>>>>>>>> quite as
> >>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
> >>>>>>>>> try that
> >>>>>>>>> either.
> >>>>>>>>>
> >>>>>>>>> Bill
> >>>>>>>> No way a caliper could stop the blade in even 4X the time
> >>>>>>>> the
> >>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad"
> >>>>>>>> and
> >>>>>>>> the blade would be quite problematic - with dust decreasing the
> >>>>>>>> stopping efficiency by a very large margin.
> >>>>>>>
>>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers
>>>>>>>> off
> >>>>>>> my '76 Lincoln might surprise you.
> >>>>>>>
> >>>>>>
> >>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know
> >>>>>> for
> >>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
> >>>>>
> >>>>> Why would something that can stop a 4000 pound car "snap" when
> >>>>> called on
> >>>>> to stop a 3 pound saw blade?
> >>>>
> >>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
> >>>
> >>> To stop the saw in a fraction of a revolution, you need rapid
> >>> application. A pyro will build pressure rapidly.
> >>
> >> I didn't think we were talking about an emergency stop.
> >> AFAIK, we're discussing a convenience stop which, in my opinion, would
> >> be satisfactorily done in a couple seconds, not milliseconds.
> >
> > Well, geez, for that a bicycle brake will work fine.
>
> Another reality check for all the people taking this thread off into the
> wild blue yonder is
> the issue of getting the blade onto the arbor in the presence of calipers
> that grip either
> side of the blade. My interest (and Mike's as well, I think) in using a
> bicycle brake was
> simply a matter of "how can I retrofit my existing table saw with a simple
> convenience
> brake?" I think the wide-opening jaws of a bicycle brake (maybe along
> with some kind of
> front-side cable disconnect to allow the calipers to drop out of the way)
> would allow enough
> clearance to get the blade on the arbor without too much trouble. This
> heavy-duty
> automotive caliber Saw-Stop alternative that everybody else is talking
> about would also have
> to provide a similar mechanism, which would of course add to the
> complexity.
In article <[email protected]>,
[email protected] says...
>
> On 10/10/10 9:22 PM, Larry Jaques wrote:
> > On Sun, 10 Oct 2010 17:30:01 -0500, -MIKE-<[email protected]>
> > wrote:
> >
> >> On 10/10/10 4:51 PM, Larry Jaques wrote:
> >>> On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE-<[email protected]>
> >>> wrote:
> >>>
> >>>> On 10/10/10 11:35 AM, willshak wrote:
> >>>>> WW wrote the following:
> >>>>>> "HeyBub"<[email protected]> wrote in message
> >>>>>> news:[email protected]...
> >>>>>>> Found this article...
> >>>>>>>
> >>>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
> >>>>>>> in the home workshop. Stationary grinders, table and radial arm
> >>>>>>> circular saws frequently turn abrasive or cutting disks that are
> >>>>>>> directly mounted on the motor's spindle. These disks have large
> >>>>>>> inertial moments that allow them to free wheel for a long time after
> >>>>>>> the power is turned off. A lengthy coast to complete stop often
> >>>>>>> amounts to a major inconvenience."
> >>>>>>>
> >>>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
> >>>>>>>
> >>>>>>>
> >>>>>>> Great ... I may rig up my table saw this way. Would be safer with a
> >>>>>>> brake. WW
> >>>>>
> >>>>> If I need to stop a spinning table saw blade in a hurry to change or
> >>>>> reset something, I find that a scrap piece of lumber makes a great blade
> >>>>> brake. Turn the saw off and slide the scrap up to the still spinning
> >>>>> blade. Blade stops in a couple of seconds. No extra parts needed.
> >>>>>
> >>>>
> >>>> Someone could make some money by developing an aftermarket saw brake,
> >>>> under the table.... pads or rollers or whatever, that would squeeze the
> >>>> blade.
> >>>
> >>> Lawsuits from the arse with the SawStop patents notwithstanding, I
> >>> think he went with the positive stop style because it's the only one
> >>> which would keep from taking a finger off. The rest spin just enough
> >>> to do serious damage.
> >>>
> >>
> >> A saw blade brake wouldn't infringe on SawStop's patent at all.
> >
> > WTF does that have to do with lawsuits? People sue to keep their
> > product on top whether they have a case or not. REAL WORLD, Mike.
> >
>
> In the "REAL WORLD" (relax, man), patent infringement law suits get
> thrown out in the first hearing, too, Larry. What, you're a patent
> attorney, too?
In any case, since EU law requires brakes already (indirectly, with an
allowed spindown time IIRC), Sawstop would have an uphill battle
claiming that they infringe its patents.
In article <[email protected]>, [email protected] says...
>
> I would think that an emergency stop mechanism would be a whole different
> magnitude than a scheduled, everyday, stop.
>
> For a finger saver an emergency stop mechanism would have to stop the blade
> in a few teeth passings. For everyday usage a couple dozen blade rotations
> would be OK too. These two situations would require different tactics.
>
> A dynamic electronic brake could vary the intensity for the two different
> scenarios and we could add the caliper to the emerg stop. A caliper probably
> wouldn't last long in everyday usage and would need to be adjusted and/or
> replaced frequently.
So how much power do you have to put into that electronic brake to stop
the blade as fast as Sawstop's physical block?
And why would a caliper not last long? A set of brake pads on a car
with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
a lot more of a workout that they would stopping a little bitty saw
blade that masses less than 1/1000 as much.
> "-MIKE-" <[email protected]> wrote in message
> news:[email protected]...
> I would prefer powered off/normal on, because the operator would get
> used to the blade always braking and in the case of a solenoid failure,
> the blade would not coast.
>
> I would also think an assembly with wheels applying just a little
> pressure to the sides of the blade would make a decent passive system.
> It would be just enough pressure to slow down the blade in a second or
> two and not enough pressure for the motor to even register the resistance.
>
> Think about how little pressure it takes with a scrap piece of wood to
> stop a coasting blade.
Larry Jaques wrote:
> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
> <[email protected]> wrote:
>>
>> As a guy who has done all of his own vehicle maintenance for 40
>> years now, I have to ask what you observed in your experiences, that
>> causes you to make this statement? I don't know if the brake
>> caliper idea is the most elegant solution, but I sure can't see
>> anything in what you are saying that would suggest it is not a
>> workable solution.
>
> Suitable placement of an air nozzle tube to clear the caliper frame
> every hour or so would go far into making this device work for more
> than an hour. You'd have to keep the sawdust from piercing the seals
> and/or building up on the frame
Not at all Larry, if you consider what a normal brake caliper in an
automobile is subject to. In comparison, the environment inside a table saw
would be a walk in the part of a caliper.
--
-Mike-
[email protected]
"Josepi" <[email protected]> wrote in
news:[email protected]:
> How about a compressed air nozzle aimed at the carbide of the blade to
> slow it to a stop?
>
> It would clean it off and compressed air is usually available.
>
That might actually have a practical application. Point the jet of air
towards the dust collection port, and perhaps dust collection can be
improved by having the stream of air going while the saw is running. As a
bonus, it would work to slow the saw blade down after shutting off the saw.
Puckdropper
--
Never teach your apprentice everything you know.
[email protected] wrote:
>
> First of all, it's just too big and heavy to fit.
Why so? A caliper does not have to be large.
> Second it's using an
> atom bomb to swat a fly. Third, it's too complex. Exactly haw are you
> going to actuate it?????
Too complex? On the contrary, it's very simple.
> Forth, how are you going to get it out of the way to change blades?
Well, one idea would be to mount it on the inside of the arbor so that it
does not even have to be removed to replace a blade.
> Fifth - How are you going to compensate for different blade
> thicknesses - or heaven help you, a DADO blade?
See above answer.
> Also, single piston or dual piston?
You are going out of your way to make this appear to be complicated now.
> and how are you going to ensure
> the pressure on both sides of the blade is equal, and application is
> even..
Both sides? Why both sides? For the discussion at hand, one side would be
ample.
> Push on one side of the blade more than the other and the blade
> goes into an oscillation/wobble and you eventually break the web out
> of the blade. Then you have a REAL safety issue!!!!!.
Sure - it you push it hard enough. No need for that level of pressure
though. Think about what forces your blade sees as you cut through a
knarley hunk of hardwood. It sees more lateral force than would be required
for a simple blade brake - which is the discussion at hand.
>
> Trust me - it's a BAD idea - and almost totally unworkable on so MANY
> levels if you understand anything about how both the saw and the break
> caliper work.
Sorry Clare - cannot trust you on this point. I see it as perfectly
workable and not subject to any of the concerns you've outlined. I do
understand both how the saw works and how calipers work but you have not
argued anything to make the idea impractical.
--
-Mike-
[email protected]
On Oct 16, 12:44=A0am, Steve Turner <[email protected]>
wrote:
> On 10/15/2010 10:46 PM, -MIKE- wrote:
>
> > On 10/15/10 10:33 PM, Josepi wrote:
> >> So you are saying the SawStop is useless and everybody knows it?
>
> > Holy cow, I hope you're just messing with us.
> > Please, for your sake, I hope you're just trying get us riled up.
>
> The guy's half troll, half dumbass, so that *has* to be the explanation..=
.
>
LOL, you think?
Yup, Just returning the absolute garnage I got from the trolling crowd that
has a hard time reading.
It happens to all of us from time to time.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Holy cow, I hope you're just messing with us.
Please, for your sake, I hope you're just trying get us riled up.
On 10/15/10 10:33 PM, Josepi wrote:
> So you are saying the SawStop is useless and everybody knows it?
>
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, [email protected]
says...
>
> How about a compressed air nozzle aimed at the carbide of the blade to slow
> it to a stop?
>
> It would clean it off and compressed air is usually available.
>
>
> <[email protected]> wrote in message
> news:[email protected]...
> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
> First of all, it's just too big and heavy to fit.
Fit what, a big cabinet?
> Second it's using an
> atom bomb to swat a fly.
So is Sawstop by that logic.
> Third, it's too complex.
More complext than Sawstop?
> Exactly haw are you
> going to actuate it?????
Trigger a gas generator.
> Forth, how are you going to get it out of the way to change blades?
Screwdriver.
> Fifth - How are you going to compensate for different blade
> thicknesses - or heaven help you, a DADO blade?
Screwdriver. It already accomodates the front and rear rotors, the
fronts are about 3/4 inch thick, the rears about 1/4, and there's abut
that much difference in pad thickness between new and worn out.
> Also, single piston or dual piston?
However many it has on it.
> and how are you going to ensure
> the pressure on both sides of the blade is equal,
The same way it happens on the car.
> and application is
> even..
The same way it happens on the car.
> Push on one side of the blade more than the other and the blade
> goes into an oscillation/wobble and you eventually break the web out
> of the blade. Then you have a REAL safety issue!!!!!.
You can say the same for a brake rotor, which actually has a "web"
instead of being a piece of uniform steel plate.
> Trust me - it's a BAD idea - and almost totally unworkable on so MANY
> levels if you understand anything about how both the saw and the break
> caliper work.
Oh, now I see the problem. We were talking about _brake_ caliper. I
guess if you use a _break_ caliper you can expect things to break.
In article <[email protected]>, [email protected] says...
>
> Me think we will wait until somebody shows a design drawing of where the
> caliper goes when the saw blade tips at a 45 degree cut.
The same place the Sawstop mechanism goes.
> I don't see this working well for a retrofit on a tablesaw with a
> tilt...maybe a production lumber yeard saw. For a new design a custom moter
> with a caliper brake would be feasible but eliminates a stock motor design
> and the price would reach the SawStop price.
>
> IMHO The dynamic brake would be more effective and less maintenance. I am
> with clare on that one but then I am a "circuitry" guy.
If you're just looking for a convenience brake either buy a European saw
or use the damned pushstick.
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> Too complex? On the contrary, it's very simple.
>
> Well, one idea would be to mount it on the inside of the arbor so that it
> does not even have to be removed to replace a blade.
>
> You are going out of your way to make this appear to be complicated now.
> Both sides? Why both sides? For the discussion at hand, one side would be
> ample.
>
>
> Sure - it you push it hard enough. No need for that level of pressure
> though. Think about what forces your blade sees as you cut through a
> knarley hunk of hardwood. It sees more lateral force than would be required
> for a simple blade brake - which is the discussion at hand.
>
>
> Sorry Clare - cannot trust you on this point. I see it as perfectly
> workable and not subject to any of the concerns you've outlined. I do
> understand both how the saw works and how calipers work but you have not
> argued anything to make the idea impractical.
In article <[email protected]>, [email protected] says...
>
> I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
> actually tilt? Has anybody actually seen the mechanism under the table?
So you're saying that people are paying 3400 bucks for a saw on which
the big wheel on the side that is supposed to adjust blade tilt doesn't
do anything? And none of the reviewers have noticed?
> What happens when the sensitive moisture sensor is full of titanic acid oak
> sawdust?
Whatever gave you the idea that there's a "sensitive moisture sensor"?
>
>
>
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> The same place the Sawstop mechanism goes.
>
>
> In article <[email protected]>, [email protected] says...
>
> > Me think we will wait until somebody shows a design drawing of where the
> > caliper goes when the saw blade tips at a 45 degree cut.
Yup, some of you just can't stop trolling with your garbage. Very hard for
anybody to take you serious after the gabage spewed.
If the shoe fits?
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Hardly new, but sometimes it's just too fun.
I still remember the go-around I had with him about how a nail gun can
kill a man from a quarter mile. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
So you are saying the SawStop is useless and everybody knows it?
Perhaps you can explain where the "titanic acid" would come from.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
So you're saying that people are paying 3400 bucks for a saw on which
the big wheel on the side that is supposed to adjust blade tilt doesn't
do anything? And none of the reviewers have noticed?
Whatever gave you the idea that there's a "sensitive moisture sensor"?
In article <[email protected]>, [email protected] says...
>
> I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
> actually tilt? Has anybody actually seen the mechanism under the table?
> What happens when the sensitive moisture sensor is full of titanic acid
> oak
> sawdust?
How about a compressed air nozzle aimed at the carbide of the blade to slow
it to a stop?
It would clean it off and compressed air is usually available.
<[email protected]> wrote in message
news:[email protected]...
On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
First of all, it's just too big and heavy to fit. Second it's using an
atom bomb to swat a fly. Third, it's too complex. Exactly haw are you
going to actuate it?????
Forth, how are you going to get it out of the way to change blades?
Fifth - How are you going to compensate for different blade
thicknesses - or heaven help you, a DADO blade?
Also, single piston or dual piston? and how are you going to ensure
the pressure on both sides of the blade is equal, and application is
even.. Push on one side of the blade more than the other and the blade
goes into an oscillation/wobble and you eventually break the web out
of the blade. Then you have a REAL safety issue!!!!!.
Trust me - it's a BAD idea - and almost totally unworkable on so MANY
levels if you understand anything about how both the saw and the break
caliper work.
Me think we will wait until somebody shows a design drawing of where the
caliper goes when the saw blade tips at a 45 degree cut.
I don't see this working well for a retrofit on a tablesaw with a
tilt...maybe a production lumber yeard saw. For a new design a custom moter
with a caliper brake would be feasible but eliminates a stock motor design
and the price would reach the SawStop price.
IMHO The dynamic brake would be more effective and less maintenance. I am
with clare on that one but then I am a "circuitry" guy.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
Too complex? On the contrary, it's very simple.
Well, one idea would be to mount it on the inside of the arbor so that it
does not even have to be removed to replace a blade.
You are going out of your way to make this appear to be complicated now.
Both sides? Why both sides? For the discussion at hand, one side would be
ample.
Sure - it you push it hard enough. No need for that level of pressure
though. Think about what forces your blade sees as you cut through a
knarley hunk of hardwood. It sees more lateral force than would be required
for a simple blade brake - which is the discussion at hand.
Sorry Clare - cannot trust you on this point. I see it as perfectly
workable and not subject to any of the concerns you've outlined. I do
understand both how the saw works and how calipers work but you have not
argued anything to make the idea impractical.
--
-Mike-
[email protected]
On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Wed, 13 Oct 2010 22:52:34 -0400, "Josepi" <[email protected]>
>> wrote:
>>
>>> As I stated posters seem to lean towards the technology they are
>>> comfortable with.
>>>
>>> The mechanics would be a nightmare to me, also. To others the
>>> electronics would be a nightmare.
>>>
>>> Contactor and resistor?...way too complicated.
>>>
>>>
>>> <[email protected]> wrote in message
>>> news:[email protected]...
>>> You want to put that monstrosity on a tilting arbour saw, mounted
>>> under the saw table and in the path of the saw-dust and have it work
>>> reliably???
>>> Not going to happen - guaranteed.
>>>
>> It's BECAUSE I was a mechanic for several decades that I would NOT use
>> a brake caliper for the application.
>
>As a guy who has done all of his own vehicle maintenance for 40 years now, I
>have to ask what you observed in your experiences, that causes you to make
>this statement? I don't know if the brake caliper idea is the most elegant
>solution, but I sure can't see anything in what you are saying that would
>suggest it is not a workable solution.
First of all, it's just too big and heavy to fit. Second it's using an
atom bomb to swat a fly. Third, it's too complex. Exactly haw are you
going to actuate it?????
Forth, how are you going to get it out of the way to change blades?
Fifth - How are you going to compensate for different blade
thicknesses - or heaven help you, a DADO blade?
Also, single piston or dual piston? and how are you going to ensure
the pressure on both sides of the blade is equal, and application is
even.. Push on one side of the blade more than the other and the blade
goes into an oscillation/wobble and you eventually break the web out
of the blade. Then you have a REAL safety issue!!!!!.
Trust me - it's a BAD idea - and almost totally unworkable on so MANY
levels if you understand anything about how both the saw and the break
caliper work.
On Sat, 16 Oct 2010 01:35:26 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Fri, 15 Oct 2010 22:29:51 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Fri, 15 Oct 2010 23:50:50 +0100, Stuart <[email protected]>
>> >> wrote:
>> >>
>> >> >In article <[email protected]>,
>> >> > <[email protected]> wrote:
>> >> >
>> >> >> That's my point. Nobody else, so far, has addressed how they would
>> >> >> control the application of this "convenience brake", however
>> >> >> implemented. My pushbutton solution was rejected out of hand - but how
>> >> >> would any of the other suggested possibilities be implemented???
>> >> >
>> >> >OK, here goes:
>> >> >
>> >> >Pair of AC solenoids, one each side of the blade holding a brake pad away
>> >> >from the blade, paralleled with feed to motor. When motor is powered
>> >> >brakes are off, when motor switched off solenoids de-energise and springs
>> >> >press pads against sides of blade. This is a "convenience" brake, no need
>> >> >for great forces to be applied. Solenoids mounted on a sliding
>> >> >arrangement, operated by a lever, which allows them to be moved out of the
>> >> >way for blade changing.
>> >> That would work - assuming there is space to mount it and the
>> >> associated bracketry. Mechanically still more complex and therefore
>> >> prone to failure.
>> >>
>> >> Generally speaking, an electronic implementation/solution is at least
>> >> twice as reliable as a mechanical solution, and the difference
>> >> increases as the mechanical complexity increases. More moving parts
>> >> means more to fail.
>> >
>> >And that is why all cars have electronic brakes . . .
>> >
>> No. but the antilock system is electronic - and it COULD be
>> mechanical.
>
>My Lincoln has mechanical antiskid. Electronic is cheaper.
>
>> RR, I believe, had a driveshaft powered hydraulic booster
>> that reduced braking pressure when the rear wheels locked. The
>> electronics are more reliable. Same with fuel injection and adjustable
>> suspension.
>
>So how do you make a mechanical system that can consider oxygen levels
>in the exhaust.
>
Not imperitive for a fuel injection system - only for a polution
control system.
On 10/15/10 8:57 PM, Josepi wrote:
> I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
> actually tilt? Has anybody actually seen the mechanism under the table?
>
> What happens when the sensitive moisture sensor is full of titanic acid oak
> sawdust?
>
Are you joking, now? Please tell me you are. (hint: I'm giving you an
out, here.)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/10 10:33 PM, Josepi wrote:
> So you are saying the SawStop is useless and everybody knows it?
>
Holy cow, I hope you're just messing with us.
Please, for your sake, I hope you're just trying get us riled up.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/2010 10:46 PM, -MIKE- wrote:
> On 10/15/10 10:33 PM, Josepi wrote:
>> So you are saying the SawStop is useless and everybody knows it?
>>
>
> Holy cow, I hope you're just messing with us.
> Please, for your sake, I hope you're just trying get us riled up.
The guy's half troll, half dumbass, so that *has* to be the explanation...
--
A. Because it makes the discussion harder to read.
Q. Why should I not top-post?
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
In article <[email protected]>, [email protected] wrote:
>On 10/15/10 10:33 PM, Josepi wrote:
>> So you are saying the SawStop is useless and everybody knows it?
>>
>
>Holy cow, I hope you're just messing with us.
>Please, for your sake, I hope you're just trying get us riled up.
.
You must be new here. Of course he is. "Josepi" is just our latest troll. Stop
feeding him, and he'll go away eventually
On 10/16/10 12:09 PM, Doug Miller wrote:
> In article<[email protected]>, [email protected] wrote:
>> On 10/15/10 10:33 PM, Josepi wrote:
>>> So you are saying the SawStop is useless and everybody knows it?
>>>
>>
>> Holy cow, I hope you're just messing with us.
>> Please, for your sake, I hope you're just trying get us riled up.
> .
> You must be new here. Of course he is. "Josepi" is just our latest troll. Stop
> feeding him, and he'll go away eventually
Hardly new, but sometimes it's just too fun.
I still remember the go-around I had with him about how a nail gun can
kill a man from a quarter mile. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/16/10 1:43 PM, Josepi wrote:
> Yup, some of you just can't stop trolling with your garbage. Very hard for
> anybody to take you serious after the gabage spewed.
>
If it makes you feel better to blame all your problems on everyone else,
good for you.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Wed, 13 Oct 2010 18:16:40 -0400, "J. Clarke"
<[email protected]> wrote:
>> Use a DC motor and a DPDT switch with a big resistor across the "stop"
>> terminals to short the motor when you shut it off. Stop a 10 inch
>> blade from 3600rpm in less trha a second with a dead short (if the
>> switch can handle it) or in about 2 seconds with a good "soft" braking
>> resistor.
>
>Which is where this thread started.
>
A really big solid state relay and a sealed explosion proof switch,
cause you do not want to start a thread about sawdust explosions.
Right?
You know you can use oars to stir stuff.
Mark
On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Wed, 13 Oct 2010 22:52:34 -0400, "Josepi" <[email protected]>
>> wrote:
>>
>>> As I stated posters seem to lean towards the technology they are
>>> comfortable with.
>>>
>>> The mechanics would be a nightmare to me, also. To others the
>>> electronics would be a nightmare.
>>>
>>> Contactor and resistor?...way too complicated.
>>>
>>>
>>> <[email protected]> wrote in message
>>> news:[email protected]...
>>> You want to put that monstrosity on a tilting arbour saw, mounted
>>> under the saw table and in the path of the saw-dust and have it work
>>> reliably???
>>> Not going to happen - guaranteed.
>>>
>> It's BECAUSE I was a mechanic for several decades that I would NOT use
>> a brake caliper for the application.
>
>As a guy who has done all of his own vehicle maintenance for 40 years now, I
>have to ask what you observed in your experiences, that causes you to make
>this statement? I don't know if the brake caliper idea is the most elegant
>solution, but I sure can't see anything in what you are saying that would
>suggest it is not a workable solution.
Suitable placement of an air nozzle tube to clear the caliper frame
every hour or so would go far into making this device work for more
than an hour. You'd have to keep the sawdust from piercing the seals
and/or building up on the frame
--
Do not taunt Happy Fun Ball!
Forget it! The name calling has started indicating no more discussion or
open minds...LOL
<[email protected]> wrote in message
news:[email protected]...
If you have a "start" and a "stop" button, generally there is a
contactor OR a solid state relay somewhere on the unit.
There are exceptions - mechanical switch controlled by 2 mechanical
linkages instead of a toggle switch
A contactor can be latching, or not latching. Latching contactors use
a start and stop putton. Non latching contactors are just relays that
take the load off the switch. Your dust collector is likely the
latter.
You can tell if you have a latching contactor by unplugging the saw
with it turned on. If it restarts when you plug it back in it's not a
latching contactor.
On Fri, 15 Oct 2010 22:29:01 -0400, "J. Clarke"
<[email protected]> wrote:
>> >
>> If you have an OFF button it is contactor controlled - you simply
>> change the contactor.
>
>So where is the "contactor" on my Ridgid table saw and my Craftman band
>saw, and why is there no "OFF" button on my contactor-controlled dust
>collector?
>
>
>
If you have a "start" and a "stop" button, generally there is a
contactor OR a solid state relay somewhere on the unit.
There are exceptions - mechanical switch controlled by 2 mechanical
linkages instead of a toggle switch
A contactor can be latching, or not latching. Latching contactors use
a start and stop putton. Non latching contactors are just relays that
take the load off the switch. Your dust collector is likely the
latter.
You can tell if you have a latching contactor by unplugging the saw
with it turned on. If it restarts when you plug it back in it's not a
latching contactor.
I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
actually tilt? Has anybody actually seen the mechanism under the table?
What happens when the sensitive moisture sensor is full of titanic acid oak
sawdust?
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
The same place the Sawstop mechanism goes.
In article <[email protected]>, [email protected] says...
> Me think we will wait until somebody shows a design drawing of where the
> caliper goes when the saw blade tips at a 45 degree cut.
In article <[email protected]>, [email protected]
says...
>
> Josepi wrote:
> > I would think that an emergency stop mechanism would be a whole different
> > magnitude than a scheduled, everyday, stop.
>
> indeed...
>
> > For a finger saver an emergency stop mechanism would have to stop the blade
> > in a few teeth passings. ...
>
> SawStop is a few (10's of iirc) msec.
>
> By several "tooth passings" a finger is already pretty well history...
Sawstop stops the blade in 1/200 of a second, according to their Web
site. At 3450 RPM that means the blade stops in .29 revolution, which
with a 60 tooth blade means that 17 teeth have had a shot at your
finger.
In article <[email protected]>,
[email protected] says...
>
> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>
> >J. Clarke wrote:
> >> In article<[email protected]>, [email protected] says...
> >>>
> >>> I would think that an emergency stop mechanism would be a whole different
> >>> magnitude than a scheduled, everyday, stop.
> >>>
> >>> For a finger saver an emergency stop mechanism would have to stop the blade
> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >>> would be OK too. These two situations would require different tactics.
> >>>
> >>> A dynamic electronic brake could vary the intensity for the two different
> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >>> replaced frequently.
> >>
> >> So how much power do you have to put into that electronic brake to stop
> >> the blade as fast as Sawstop's physical block?
> >>
> >> And why would a caliper not last long? A set of brake pads on a car
> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >> a lot more of a workout that they would stopping a little bitty saw
> >> blade that masses less than 1/1000 as much.
> >
> >The physics on that seem interesting. A little like stopping a speeding
> >bullet on a dime--it challenges my imagination. Probably not quite as
> >difficult as stopping a lightning bolt, but I wouldn't want to try that
> >either.
> >
> >Bill
> No way a caliper could stop the blade in even 4X the time the
> saw-stop does. And keeping dust out of the gap between tha "pad" and
> the blade would be quite problematic - with dust decreasing the
> stopping efficiency by a very large margin.
I suspect that a small pyrotechnic pressurizing one of the calipers off
my '76 Lincoln might surprise you.
On Thu, 14 Oct 2010 11:27:20 -0500, Steve Turner
<[email protected]> wrote:
>On 10/14/2010 11:15 AM, -MIKE- wrote:
>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>> Another reality check for all the people taking this thread off into the
>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>> presence of calipers that grip either side of the blade. My interest
>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>> matter of "how can I retrofit my existing table saw with a simple
>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>> (maybe along with some kind of front-side cable disconnect to allow the
>>> calipers to drop out of the way) would allow enough clearance to get the
>>> blade on the arbor without too much trouble.
>>
>> Heck, I think if it was mounted closer to the arbor than the edge, one pad on
>> the arbor side of the blade would be sufficient for a convenience slow/stop.
>
>That very well could be true, and you could also use such a brake with dado
>blades of any thickness... Interesting observation there Mike; I'm gonna have
>to go do some peeking inside my Unisaw to see what the possibilities are. :-)
If you want to put a friction brake on a saw blade you need to do it
on the "non-blade" side of the arbour. Put the brake on the pulley if
belt drive, or the "fan end" of the motor if direct drive.
The only problem there is, if you stop the arbour too quickly the
arbour nut will wind off as the blade trys to keep spinning.
Same thing happens if DC injection on ann AC motor or
resistive(regenerative) braking on a DC motor is too harsh..
That's why the "saw stop" HAS to stop the blade directly. Stopping the
blade that fast through the arbour would inevitably wind the blade off
the arbour before the blade came to a safe stop.
That happens freuently to my Milwalkee 12V drill. The brake stops the
insides but the chuck wants to keep on going and undoes itself and the bit
falls out. The chuck even appears to have a dual gear ratio tightening
mechanism.
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
Valid point, but again, we're not talking about a Saw-Stop equivalent here,
only a "convenience" brake that stops the blade in a second or two. Unless
you've dangerously under-tightened the arbor nut (or ridiculously
over-engineered the brake) that's not likely to cause enough centrifugal
force
to loosen the arbor nut.
--
Any given amount of traffic flow, no matter how
sparse, will expand to fill all available lanes.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/2010 2:29 PM, [email protected] wrote:
> On Thu, 14 Oct 2010 11:27:20 -0500, Steve Turner
> <[email protected]> wrote:
>
>> On 10/14/2010 11:15 AM, -MIKE- wrote:
>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>> Another reality check for all the people taking this thread off into the
>>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>>> presence of calipers that grip either side of the blade. My interest
>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>> matter of "how can I retrofit my existing table saw with a simple
>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>> calipers to drop out of the way) would allow enough clearance to get the
>>>> blade on the arbor without too much trouble.
>>>
>>> Heck, I think if it was mounted closer to the arbor than the edge, one pad on
>>> the arbor side of the blade would be sufficient for a convenience slow/stop.
>>
>> That very well could be true, and you could also use such a brake with dado
>> blades of any thickness... Interesting observation there Mike; I'm gonna have
>> to go do some peeking inside my Unisaw to see what the possibilities are. :-)
> If you want to put a friction brake on a saw blade you need to do it
> on the "non-blade" side of the arbour. Put the brake on the pulley if
> belt drive, or the "fan end" of the motor if direct drive.
>
> The only problem there is, if you stop the arbour too quickly the
> arbour nut will wind off as the blade trys to keep spinning.
> Same thing happens if DC injection on ann AC motor or
> resistive(regenerative) braking on a DC motor is too harsh..
>
> That's why the "saw stop" HAS to stop the blade directly. Stopping the
> blade that fast through the arbour would inevitably wind the blade off
> the arbour before the blade came to a safe stop.
Valid point, but again, we're not talking about a Saw-Stop equivalent here,
only a "convenience" brake that stops the blade in a second or two. Unless
you've dangerously under-tightened the arbor nut (or ridiculously
over-engineered the brake) that's not likely to cause enough centrifugal force
to loosen the arbor nut.
--
Any given amount of traffic flow, no matter how
sparse, will expand to fill all available lanes.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/10 2:29 PM, [email protected] wrote:
> On Thu, 14 Oct 2010 11:27:20 -0500, Steve Turner
> The only problem there is, if you stop the arbour too quickly the
> arbour nut will wind off as the blade trys to keep spinning.
> Same thing happens if DC injection on ann AC motor or
> resistive(regenerative) braking on a DC motor is too harsh..
>
Neither of us is trying to stop the blade that fast.
> That's why the "saw stop" HAS to stop the blade directly. Stopping the
> blade that fast through the arbour would inevitably wind the blade off
> the arbour before the blade came to a safe stop.
I seriously doubt that was even the slightest consideration for the
inventor of the SawStop.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, [email protected] says...
>
> J. Clarke wrote:
> > In article<[email protected]>,
> > [email protected] says...
> >>
> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
> >>
> >>> J. Clarke wrote:
> >>>> In article<[email protected]>, [email protected] says...
> >>>>>
> >>>>> I would think that an emergency stop mechanism would be a whole different
> >>>>> magnitude than a scheduled, everyday, stop.
> >>>>>
> >>>>> For a finger saver an emergency stop mechanism would have to stop the blade
> >>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >>>>> would be OK too. These two situations would require different tactics.
> >>>>>
> >>>>> A dynamic electronic brake could vary the intensity for the two different
> >>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >>>>> replaced frequently.
> >>>>
> >>>> So how much power do you have to put into that electronic brake to stop
> >>>> the blade as fast as Sawstop's physical block?
> >>>>
> >>>> And why would a caliper not last long? A set of brake pads on a car
> >>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >>>> a lot more of a workout that they would stopping a little bitty saw
> >>>> blade that masses less than 1/1000 as much.
> >>>
> >>> The physics on that seem interesting. A little like stopping a speeding
> >>> bullet on a dime--it challenges my imagination. Probably not quite as
> >>> difficult as stopping a lightning bolt, but I wouldn't want to try that
> >>> either.
> >>>
> >>> Bill
> >> No way a caliper could stop the blade in even 4X the time the
> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >> the blade would be quite problematic - with dust decreasing the
> >> stopping efficiency by a very large margin.
> >
> > I suspect that a small pyrotechnic pressurizing one of the calipers off
> > my '76 Lincoln might surprise you.
> >
>
> When it snapped (seriously)? I'm not an engineer, so I don't know for
> sure. I just wouldn't be surprised. Maybe someone else can opine.
Why would something that can stop a 4000 pound car "snap" when called on
to stop a 3 pound saw blade?
"Markem" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 14 Oct 2010 10:58:43 -0700 (PDT), Robatoy
> <[email protected]> wrote:
>
>>I propose an air bag. Electronically triggered, it throws you
>>backwards across the shop and away from the table saw. Punches you
>>right in the chest with the option for a double bag for some people
>>here in which case the second bag knocks some sense in them. We can
>>glue on a boxing glove for that operation...just a 4 oz. one; you want
>>it to hurt a little.
>>One can mount the boxing glove on an expanding multi-pivot articulated
>>parallelogram.
>>What a stellar idea.
>>I'm talking to investors now.
>>They want to call the company ACME.
>
> Would make a great cartoon to pass about the Internet, if twas done in
> animation might even go viral. But you might want to have a huge
> catchers mitt behind the punchee.
>
Is Wiley Coyote available as a spokesperson?
On Thu, 14 Oct 2010 15:09:44 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 2:29 PM, [email protected] wrote:
>> On Thu, 14 Oct 2010 11:27:20 -0500, Steve Turner
>> The only problem there is, if you stop the arbour too quickly the
>> arbour nut will wind off as the blade trys to keep spinning.
>> Same thing happens if DC injection on ann AC motor or
>> resistive(regenerative) braking on a DC motor is too harsh..
>>
>
>Neither of us is trying to stop the blade that fast.
>
>
>> That's why the "saw stop" HAS to stop the blade directly. Stopping the
>> blade that fast through the arbour would inevitably wind the blade off
>> the arbour before the blade came to a safe stop.
>
>I seriously doubt that was even the slightest consideration for the
>inventor of the SawStop.
From what I was told it WAS.
On 10/14/2010 2:30 PM, [email protected] wrote:
> On Thu, 14 Oct 2010 11:57:58 -0500, Steve Turner
> <[email protected]> wrote:
>
>> On 10/14/2010 11:47 AM, -MIKE- wrote:
>>> On 10/14/10 11:27 AM, Steve Turner wrote:
>>>> On 10/14/2010 11:15 AM, -MIKE- wrote:
>>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>>> Another reality check for all the people taking this thread off into the
>>>>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>>>>> presence of calipers that grip either side of the blade. My interest
>>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>>>> calipers to drop out of the way) would allow enough clearance to get the
>>>>>> blade on the arbor without too much trouble.
>>>>>
>>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>>> pad on
>>>>> the arbor side of the blade would be sufficient for a convenience
>>>>> slow/stop.
>>>>
>>>> That very well could be true, and you could also use such a brake with
>>>> dado blades of any thickness... Interesting observation there Mike; I'm
>>>> gonna have to go do some peeking inside my Unisaw to see what the
>>>> possibilities are. :-)
>>>>
>>>
>>> Good. It's about time that happens to someone *else.*
>>> Let me know what you come up with so I can take credit for it. :-)
>>
>> Well, peek I did, but it seems the opportunities for mounting such a device, on
>> the Unisaw at least, are virtually nil. There are just too many clearance
>> problems to overcome. However, it does seem possible that I could mount a thin
>> disc to the motor pulley (one that's a couple of inches larger in diameter) and
>> apply caliper pressure to that instead.
>
> Like I said.
After I already said it.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On Thu, 14 Oct 2010 10:58:43 -0700 (PDT), Robatoy
<[email protected]> wrote:
>I propose an air bag. Electronically triggered, it throws you
>backwards across the shop and away from the table saw. Punches you
>right in the chest with the option for a double bag for some people
>here in which case the second bag knocks some sense in them. We can
>glue on a boxing glove for that operation...just a 4 oz. one; you want
>it to hurt a little.
>One can mount the boxing glove on an expanding multi-pivot articulated
>parallelogram.
>What a stellar idea.
>I'm talking to investors now.
>They want to call the company ACME.
Would make a great cartoon to pass about the Internet, if twas done in
animation might even go viral. But you might want to have a huge
catchers mitt behind the punchee.
Mark
On Thu, 14 Oct 2010 11:57:58 -0500, Steve Turner
<[email protected]> wrote:
>On 10/14/2010 11:47 AM, -MIKE- wrote:
>> On 10/14/10 11:27 AM, Steve Turner wrote:
>>> On 10/14/2010 11:15 AM, -MIKE- wrote:
>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>> Another reality check for all the people taking this thread off into the
>>>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>>>> presence of calipers that grip either side of the blade. My interest
>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>>> calipers to drop out of the way) would allow enough clearance to get the
>>>>> blade on the arbor without too much trouble.
>>>>
>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>> pad on
>>>> the arbor side of the blade would be sufficient for a convenience
>>>> slow/stop.
>>>
>>> That very well could be true, and you could also use such a brake with
>>> dado blades of any thickness... Interesting observation there Mike; I'm
>>> gonna have to go do some peeking inside my Unisaw to see what the
>>> possibilities are. :-)
>>>
>>
>> Good. It's about time that happens to someone *else.*
>> Let me know what you come up with so I can take credit for it. :-)
>
>Well, peek I did, but it seems the opportunities for mounting such a device, on
>the Unisaw at least, are virtually nil. There are just too many clearance
>problems to overcome. However, it does seem possible that I could mount a thin
>disc to the motor pulley (one that's a couple of inches larger in diameter) and
>apply caliper pressure to that instead.
Like I said.
> The calipers would have to be mounted
>to a bracket that attaches to the motor housing, but that shouldn't be too hard
>to accomplish.
In article <[email protected]>, [email protected]
says...
>
> I doubt most people use a pusher stick to cut plywood sheets.
>
> Now we have to define "close"...LOL
General rule is don't have your hands in in line with the blade, or
within 4 inches of it in any direction.
> "Steve Turner" <[email protected]> wrote in message
> news:[email protected]...
> Would I be correct in assuming you were pushing the wood into the blade with
> your bare hands rather than using a push jig or Gripper or something
> similar?
>
>
>
> On 10/12/2010 9:19 PM, Hoosierpopi wrote:
> > On Oct 12, 12:21 pm, Steve Turner<[email protected]>
> > wrote:
> >
> > wildly advancing your fingers towards the blade,
> >
> > As is done when, say, you are pushing a bit of wood into the saw and
> > it jerks out of place and you essentially "fall" forward now that the
> > wood is no longer offering resistance?
>
> I've read that about five times and have tried to visualize what you're
> talking
> about, but I'm still puzzled.
>
> > Of course, the blade never stop turning at all on the saw I was using,
> > but I did manage to put three finges and a thumb in its path before
> > realizing I was cutting skin and bone - and jerked back.
> >
> > Only cut clean through one digit and got it sewed and screwed back
> > on.
In article <[email protected]>, [email protected] says...
>
> J. Clarke wrote:
> > In article<[email protected]>, [email protected] says...
> >>
> >> J. Clarke wrote:
> >>> In article<[email protected]>,
> >>> [email protected] says...
> >>>>
> >>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
> >>>>
> >>>>> J. Clarke wrote:
> >>>>>> In article<[email protected]>, [email protected] says...
> >>>>>>>
> >>>>>>> I would think that an emergency stop mechanism would be a whole different
> >>>>>>> magnitude than a scheduled, everyday, stop.
> >>>>>>>
> >>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
> >>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >>>>>>> would be OK too. These two situations would require different tactics.
> >>>>>>>
> >>>>>>> A dynamic electronic brake could vary the intensity for the two different
> >>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >>>>>>> replaced frequently.
> >>>>>>
> >>>>>> So how much power do you have to put into that electronic brake to stop
> >>>>>> the blade as fast as Sawstop's physical block?
> >>>>>>
> >>>>>> And why would a caliper not last long? A set of brake pads on a car
> >>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >>>>>> a lot more of a workout that they would stopping a little bitty saw
> >>>>>> blade that masses less than 1/1000 as much.
> >>>>>
> >>>>> The physics on that seem interesting. A little like stopping a speeding
> >>>>> bullet on a dime--it challenges my imagination. Probably not quite as
> >>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
> >>>>> either.
> >>>>>
> >>>>> Bill
> >>>> No way a caliper could stop the blade in even 4X the time the
> >>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >>>> the blade would be quite problematic - with dust decreasing the
> >>>> stopping efficiency by a very large margin.
> >>>
> >>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>> my '76 Lincoln might surprise you.
> >>>
> >>
> >> When it snapped (seriously)? I'm not an engineer, so I don't know for
> >> sure. I just wouldn't be surprised. Maybe someone else can opine.
> >
> > Why would something that can stop a 4000 pound car "snap" when called on
> > to stop a 3 pound saw blade?
>
> "Pyrotechnics" rather than a master cylinder with brake fluid?
To stop the saw in a fraction of a revolution, you need rapid
application. A pyro will build pressure rapidly.
Larry Jaques wrote:
> On Fri, 15 Oct 2010 13:47:20 -0400, [email protected] wrote:
>
>> On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> Josepi wrote:
>>>
>>>> Disc brake were around for a lot longer than the ABS systems were ever
>>>> implemented.
>>>> Disc brakes were not sdesigned to "lock up" but rather be more linear
>>>> than shoe brake systems, and fade less.
>>>>
>>>
>>> You are correct that disk brakes have been around a lot longer than ABS has,
>>> but if you believe that disk brakes will not lock up then you simply need to
>>> drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
>>> Why do you think ABS exists?
>> Because most drivers don't (according to our governments and highway
>> safety people) have the brains to release their brakes when the wheels
>> start to slide.
>
> Most drivers don't know how to _steer_ a car, let alone -drive- one.
Well, it's hard for folks to talk on the cell phone and text and adjust
the radio, as well as drive, all at the same time... Maybe your
expectations are too high? Can you grade on a curve? : )
Bill
On Fri, 15 Oct 2010 13:47:20 -0400, [email protected] wrote:
>On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
><[email protected]> wrote:
>
>>Josepi wrote:
>>
>>> Disc brake were around for a lot longer than the ABS systems were ever
>>> implemented.
>>> Disc brakes were not sdesigned to "lock up" but rather be more linear
>>> than shoe brake systems, and fade less.
>>>
>>
>>You are correct that disk brakes have been around a lot longer than ABS has,
>>but if you believe that disk brakes will not lock up then you simply need to
>>drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
>>Why do you think ABS exists?
> Because most drivers don't (according to our governments and highway
>safety people) have the brains to release their brakes when the wheels
>start to slide.
Most drivers don't know how to _steer_ a car, let alone -drive- one.
--
Do not taunt Happy Fun Ball!
In article <[email protected]>,
[email protected] says...
>
> On 10/13/10 9:43 AM, J. Clarke wrote:
> > In article<[email protected]>, [email protected] says...
> >>
> >> J. Clarke wrote:
> >>> In article<[email protected]>, [email protected] says...
> >>>>
> >>>> J. Clarke wrote:
> >>>>> In article<[email protected]>,
> >>>>> [email protected] says...
> >>>>>>
> >>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
> >>>>>>
> >>>>>>> J. Clarke wrote:
> >>>>>>>> In article<[email protected]>, [email protected] says...
> >>>>>>>>>
> >>>>>>>>> I would think that an emergency stop mechanism would be a whole different
> >>>>>>>>> magnitude than a scheduled, everyday, stop.
> >>>>>>>>>
> >>>>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
> >>>>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >>>>>>>>> would be OK too. These two situations would require different tactics.
> >>>>>>>>>
> >>>>>>>>> A dynamic electronic brake could vary the intensity for the two different
> >>>>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >>>>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >>>>>>>>> replaced frequently.
> >>>>>>>>
> >>>>>>>> So how much power do you have to put into that electronic brake to stop
> >>>>>>>> the blade as fast as Sawstop's physical block?
> >>>>>>>>
> >>>>>>>> And why would a caliper not last long? A set of brake pads on a car
> >>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >>>>>>>> a lot more of a workout that they would stopping a little bitty saw
> >>>>>>>> blade that masses less than 1/1000 as much.
> >>>>>>>
> >>>>>>> The physics on that seem interesting. A little like stopping a speeding
> >>>>>>> bullet on a dime--it challenges my imagination. Probably not quite as
> >>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
> >>>>>>> either.
> >>>>>>>
> >>>>>>> Bill
> >>>>>> No way a caliper could stop the blade in even 4X the time the
> >>>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >>>>>> the blade would be quite problematic - with dust decreasing the
> >>>>>> stopping efficiency by a very large margin.
> >>>>>
> >>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>>>> my '76 Lincoln might surprise you.
> >>>>>
> >>>>
> >>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
> >>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
> >>>
> >>> Why would something that can stop a 4000 pound car "snap" when called on
> >>> to stop a 3 pound saw blade?
> >>
> >> "Pyrotechnics" rather than a master cylinder with brake fluid?
> >
> > To stop the saw in a fraction of a revolution, you need rapid
> > application. A pyro will build pressure rapidly.
>
> I didn't think we were talking about an emergency stop.
> AFAIK, we're discussing a convenience stop which, in my opinion, would
> be satisfactorily done in a couple seconds, not milliseconds.
Well, geez, for that a bicycle brake will work fine.
In article <[email protected]>, [email protected] says...
>
> J. Clarke wrote:
>
> >>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>>>> my '76 Lincoln might surprise you.
> >>>>>
> >>>> Bill>
> >>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
> >>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>
> >>>J. Clarke>
> >>> Why would something that can stop a 4000 pound car "snap" when called on
> >>> to stop a 3 pound saw blade?
>
> >> Bill>
> >> "Pyrotechnics" rather than a master cylinder with brake fluid?
> >
> >J. Clarke>
> > To stop the saw in a fraction of a revolution, you need rapid
> > application. A pyro will build pressure rapidly.
>
> That is what I what I might expect to increase the probability of failure.
>
> Given blade radius and density, and rpm, you could probably integrate to
> compute the (foot-pounds of) energy that need to be stopped in a small
> fraction of a second (I hope that the dust on the blade won't be an
> issue). :) I've seen you post in another "forum" so I believe you are
> up to the calculation. I do not have engineering background to back me
> up, I'm just thinking it through with you and everyone else who is
> reading. Evidently, you'll need to generate the equivalent of an equal
> and opposite amount of energy. This means, I think, that you only get
> the benefit of a "projection" (dot product) and not all of the force you
> can apply to the side of the blade. My reasoning could definitely be
> off, maybe a physicist or engineer could help out?
Disk brakes work by friction. The energy comes off as heat. Apply F to
the brake, k * F is the braking force where k is the coefficient of
friction.
Back of the envelope it looks like the Lincoln brake at Lincoln pressure
can stop it in about 1/3 revolution. Don't know how much higher
pressure that caliper can take--at 2x the pressure might be able to do
it in 1/6 revolution, which puts it in Sawstop territory.
On Fri, 15 Oct 2010 17:56:53 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Fri, 15 Oct 2010 09:49:34 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>, [email protected] says...
>> >>
>> >> Disc brake were around for a lot longer than the ABS systems were ever
>> >> implemented.
>> >> Disc brakes were not sdesigned to "lock up" but rather be more linear than
>> >> shoe brake systems, and fade less.
>> >>
>> >> "Mike Marlow" <[email protected]> wrote in message
>> >> news:[email protected]...
>> >> No they aren't. ABS systems are designed to prevent the wheel from locking
>> >> up, but disk brakes aren't. In fact, quite the opposite, they are designed
>> >> to lock up but rely upon the ABS to govern them so they don't.
>> >
>> >They're not "designed to lock up", they're designed as a compromise
>> >between maximum braking force, fade, pad wear, weight, and cost. Most
>> >disk brakes can be locked.
>> >
>> >ABS is intended to save your ass when there's poor traction by
>> >preventing lock--it will also prevent lock on good surfaces but
>> >generally isn't needed for that purpose.
>> >
>> >> Scott Lurndal wrote:
>> >> > On the other hand, disc brakes are designed so they don't lock up,
>> >> > this includes the materials used as well plus the modern ABS
>> >> > electronics.
>> >> >
>> >
>> I've had more "success" locking drum brakes on dry pavement than
>> disks. For CAFE reasons they put the lightest disk brake assembly they
>> can get away with on most vehicles.
>
>I don't see locking brakes as "success" but I can if I want to lock up
>my Grand Cherokee on a dry road.
>
>And we were talking about a caliper from a '76 Lincoln, which has
>absolutely _nothing_ "light" on it.
Well, the Ford Aerostar with factory pads could never slide the front
wheels on dry pavement - and it only had rear ABS. When I put carbon
metallic "taxi duty" pads on it I could finally get enough braking
action to lock the wheels whenever I wanted to.
I kinda missed the 1976 part - yes, it was still pretty heavy - but
not as heavy as pre-1970
In article <[email protected]>,
[email protected] says...
>
> On 10/13/10 12:06 PM, Steve Turner wrote:
> > On 10/13/2010 12:00 PM, Bill wrote:
> >> -MIKE- wrote:
> >>> Someone brought SawStop into the discussion, which took things on a
> >>> tangent.
> >>> We started out discussing the OP's link to a set of motor reversing
> >>> instructions as a way to slow down the blade for convenience. Then I
> >>> proposed the use of a bicycle brake... and things went from there.
> >>>
> >> Properly done, I bicycle brake sounds like a good idea! I'd hate to
> >> read about flying parts.
> >
> > AHEM. I believe *I* was the one who proposed the use of the bicycle
> > brake. That -MIKE- character is trying to steal my idea. :-)
> >
>
> Welllll, looks like I own someone a beer.
> Yeppers, I said, "...aftermarket saw brake, under the table.... pads or
> rollers or whatever, that would squeeze the blade," and then you brought
> up the bike brake.
>
> A good inventor is a better thief. :-)
And Nikolai Yvanovich Lobachevski is his _name_ . . .
In article <[email protected]>, [email protected] says...
>
> J. Clarke wrote:
>
>
> >>> As is done when, say, you are pushing a bit of wood into the saw and
> >>> it jerks out of place and you essentially "fall" forward now that the
> >>> wood is no longer offering resistance?
> >>
> >> I've read that about five times and have tried to visualize what you're
> >> talking
> >> about, but I'm still puzzled.
>
> Think about what would happen if you were walking with a cane, and the
> tip of the cane slipped on some ice. It's analogous.
Uh, J. Clarke didn't write _any_ of that.
In article <[email protected]>,
[email protected] says...
>
> On 10/13/2010 02:32 PM, J. Clarke wrote:
> > In article<[email protected]>,
> > [email protected] says...
> >>
> >> On 10/13/10 9:43 AM, J. Clarke wrote:
> >>> In article<[email protected]>, [email protected] says...
> >>>>
> >>>> J. Clarke wrote:
> >>>>> In article<[email protected]>, [email protected] says...
> >>>>>>
> >>>>>> J. Clarke wrote:
> >>>>>>> In article<[email protected]>,
> >>>>>>> [email protected] says...
> >>>>>>>>
> >>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
> >>>>>>>>
> >>>>>>>>> J. Clarke wrote:
> >>>>>>>>>> In article<[email protected]>, [email protected] says...
> >>>>>>>>>>>
> >>>>>>>>>>> I would think that an emergency stop mechanism would be a whole different
> >>>>>>>>>>> magnitude than a scheduled, everyday, stop.
> >>>>>>>>>>>
> >>>>>>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
> >>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >>>>>>>>>>> would be OK too. These two situations would require different tactics.
> >>>>>>>>>>>
> >>>>>>>>>>> A dynamic electronic brake could vary the intensity for the two different
> >>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >>>>>>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >>>>>>>>>>> replaced frequently.
> >>>>>>>>>>
> >>>>>>>>>> So how much power do you have to put into that electronic brake to stop
> >>>>>>>>>> the blade as fast as Sawstop's physical block?
> >>>>>>>>>>
> >>>>>>>>>> And why would a caliper not last long? A set of brake pads on a car
> >>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >>>>>>>>>> a lot more of a workout that they would stopping a little bitty saw
> >>>>>>>>>> blade that masses less than 1/1000 as much.
> >>>>>>>>>
> >>>>>>>>> The physics on that seem interesting. A little like stopping a speeding
> >>>>>>>>> bullet on a dime--it challenges my imagination. Probably not quite as
> >>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
> >>>>>>>>> either.
> >>>>>>>>>
> >>>>>>>>> Bill
> >>>>>>>> No way a caliper could stop the blade in even 4X the time the
> >>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >>>>>>>> the blade would be quite problematic - with dust decreasing the
> >>>>>>>> stopping efficiency by a very large margin.
> >>>>>>>
> >>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>>>>>> my '76 Lincoln might surprise you.
> >>>>>>>
> >>>>>>
> >>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
> >>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
> >>>>>
> >>>>> Why would something that can stop a 4000 pound car "snap" when called on
> >>>>> to stop a 3 pound saw blade?
> >>>>
> >>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
> >>>
> >>> To stop the saw in a fraction of a revolution, you need rapid
> >>> application. A pyro will build pressure rapidly.
> >>
> >> I didn't think we were talking about an emergency stop.
> >> AFAIK, we're discussing a convenience stop which, in my opinion, would
> >> be satisfactorily done in a couple seconds, not milliseconds.
> >
> > Well, geez, for that a bicycle brake will work fine.
>
> Another reality check for all the people taking this thread off into the wild blue yonder is
> the issue of getting the blade onto the arbor in the presence of calipers that grip either
> side of the blade. My interest (and Mike's as well, I think) in using a bicycle brake was
> simply a matter of "how can I retrofit my existing table saw with a simple convenience
> brake?" I think the wide-opening jaws of a bicycle brake (maybe along with some kind of
> front-side cable disconnect to allow the calipers to drop out of the way) would allow enough
> clearance to get the blade on the arbor without too much trouble. This heavy-duty
> automotive caliber Saw-Stop alternative that everybody else is talking about would also have
> to provide a similar mechanism, which would of course add to the complexity.
C-clamp.
In article <[email protected]>, [email protected] says...
>
> Spoken like a true woodworker...LOL
Seriously that's how you compress the piston on the brakes on a Jeep--
put a c-clamp on it.
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> C-clamp.
>
>
>
>
> In article <[email protected]>,
> [email protected] says...
> >
> > On 10/13/2010 02:32 PM, J. Clarke wrote:
> > > In article<[email protected]>,
> > > [email protected] says...
> > >>
> > >> On 10/13/10 9:43 AM, J. Clarke wrote:
> > >>> In article<[email protected]>, [email protected] says...
> > >>>>
> > >>>> J. Clarke wrote:
> > >>>>> In article<[email protected]>, [email protected] says...
> > >>>>>>
> > >>>>>> J. Clarke wrote:
> > >>>>>>> In article<[email protected]>,
> > >>>>>>> [email protected] says...
> > >>>>>>>>
> > >>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]>
> > >>>>>>>> wrote:
> > >>>>>>>>
> > >>>>>>>>> J. Clarke wrote:
> > >>>>>>>>>> In article<[email protected]>, [email protected]
> > >>>>>>>>>> says...
> > >>>>>>>>>>>
> > >>>>>>>>>>> I would think that an emergency stop mechanism would be a
> > >>>>>>>>>>> whole different
> > >>>>>>>>>>> magnitude than a scheduled, everyday, stop.
> > >>>>>>>>>>>
> > >>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
> > >>>>>>>>>>> stop the blade
> > >>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
> > >>>>>>>>>>> blade rotations
> > >>>>>>>>>>> would be OK too. These two situations would require different
> > >>>>>>>>>>> tactics.
> > >>>>>>>>>>>
> > >>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
> > >>>>>>>>>>> two different
> > >>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
> > >>>>>>>>>>> caliper probably
> > >>>>>>>>>>> wouldn't last long in everyday usage and would need to be
> > >>>>>>>>>>> adjusted and/or
> > >>>>>>>>>>> replaced frequently.
> > >>>>>>>>>>
> > >>>>>>>>>> So how much power do you have to put into that electronic brake
> > >>>>>>>>>> to stop
> > >>>>>>>>>> the blade as fast as Sawstop's physical block?
> > >>>>>>>>>>
> > >>>>>>>>>> And why would a caliper not last long? A set of brake pads on
> > >>>>>>>>>> a car
> > >>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a
> > >>>>>>>>>> Hell of
> > >>>>>>>>>> a lot more of a workout that they would stopping a little bitty
> > >>>>>>>>>> saw
> > >>>>>>>>>> blade that masses less than 1/1000 as much.
> > >>>>>>>>>
> > >>>>>>>>> The physics on that seem interesting. A little like stopping a
> > >>>>>>>>> speeding
> > >>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
> > >>>>>>>>> quite as
> > >>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
> > >>>>>>>>> try that
> > >>>>>>>>> either.
> > >>>>>>>>>
> > >>>>>>>>> Bill
> > >>>>>>>> No way a caliper could stop the blade in even 4X the time
> > >>>>>>>> the
> > >>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad"
> > >>>>>>>> and
> > >>>>>>>> the blade would be quite problematic - with dust decreasing the
> > >>>>>>>> stopping efficiency by a very large margin.
> > >>>>>>>
> >>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers
> >>>>>>>> off
> > >>>>>>> my '76 Lincoln might surprise you.
> > >>>>>>>
> > >>>>>>
> > >>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know
> > >>>>>> for
> > >>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
> > >>>>>
> > >>>>> Why would something that can stop a 4000 pound car "snap" when
> > >>>>> called on
> > >>>>> to stop a 3 pound saw blade?
> > >>>>
> > >>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
> > >>>
> > >>> To stop the saw in a fraction of a revolution, you need rapid
> > >>> application. A pyro will build pressure rapidly.
> > >>
> > >> I didn't think we were talking about an emergency stop.
> > >> AFAIK, we're discussing a convenience stop which, in my opinion, would
> > >> be satisfactorily done in a couple seconds, not milliseconds.
> > >
> > > Well, geez, for that a bicycle brake will work fine.
> >
> > Another reality check for all the people taking this thread off into the
> > wild blue yonder is
> > the issue of getting the blade onto the arbor in the presence of calipers
> > that grip either
> > side of the blade. My interest (and Mike's as well, I think) in using a
> > bicycle brake was
> > simply a matter of "how can I retrofit my existing table saw with a simple
> > convenience
> > brake?" I think the wide-opening jaws of a bicycle brake (maybe along
> > with some kind of
> > front-side cable disconnect to allow the calipers to drop out of the way)
> > would allow enough
> > clearance to get the blade on the arbor without too much trouble. This
> > heavy-duty
> > automotive caliber Saw-Stop alternative that everybody else is talking
> > about would also have
> > to provide a similar mechanism, which would of course add to the
> > complexity.
Now we know what the "J." stands for...."Jeep"
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
Seriously that's how you compress the piston on the brakes on a Jeep--
put a c-clamp on it.
In article <[email protected]>, [email protected] says...
>
> Spoken like a true woodworker...LOL
-MIKE- wrote:
>
> I would prefer powered off/normal on, because the operator would get
> used to the blade always braking and in the case of a solenoid
> failure, the blade would not coast.
>
> I would also think an assembly with wheels applying just a little
> pressure to the sides of the blade would make a decent passive system.
> It would be just enough pressure to slow down the blade in a second or
> two and not enough pressure for the motor to even register the
> resistance.
> Think about how little pressure it takes with a scrap piece of wood to
> stop a coasting blade.
Isn't there an old Indian trick about a spinning piece of wood and starting
a fire?
I think the main pint for all of us is
*** think *** about what could happen and then prevent it.
In safety training they call this a "barrier"
Minimize the chances with a "barrier". If you cannot absolutely prevent it
think
"Do I have to do this at all" and "Is there another way" and "How can I
make is less risk"
Minimize the damage, if should it happen anyway.
"Puckdropper" <puckdropper(at)yahoo(dot)com> wrote in message
news:[email protected]...
Trust your feelings, Steve.
I used that style of push stick for years, until I was cutting a small
piece and pressure on only the one point caused the piece to move and
catch on the back of the blade. The resulting kickback hit me in the
dust mask and broke the push stick. I will not use that style again.
Puckdropper
--
Never teach your apprentice everything you know.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
> On 10/10/10 7:51 PM, Steve Turner wrote:
>>> Someone could make some money by developing an aftermarket saw brake,
>>> under the
>>> table.... pads or rollers or whatever, that would squeeze the blade.
>>
>> I've always wondered if a set of good quality bicycle brakes couldn't be
>> safely mounted on the trunnion to perform that very task. Route the
>> cable to the front of the saw to a hand or foot operated lever and there
>> ya go.
>>
>
> Interesting. There is certainly a lot for force against a bike brake
> than a coasting saw blade/motor. I think a simple spring and
> electromagnet/solenoid would do the trick in the same way an electric
>about 6 seconds. door bell works.
> No electric current: spring holds brakes closed.
> Electric current: solenoid pulls brakes open.
> A manual cable or secondary electric source could be added for manual
> brake release.
I have a Delta radial arm that uses an electromagnet and puck against a disk
of the opposite side of the motor from the blade. Fair function- stops the
blade in about 6 seconds.
--
Jim in NC
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
> On 10/10/2010 11:54 AM, -MIKE- wrote:
>> On 10/10/10 11:35 AM, willshak wrote:
>>> WW wrote the following:
>>>> "HeyBub" <[email protected]> wrote in message
>>>> news:[email protected]...
>>>>> Found this article...
>>>>>
>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>>> in the home workshop. Stationary grinders, table and radial arm
>>>>> circular saws frequently turn abrasive or cutting disks that are
>>>>> directly mounted on the motor's spindle. These disks have large
>>>>> inertial moments that allow them to free wheel for a long time after
>>>>> the power is turned off. A lengthy coast to complete stop often
>>>>> amounts to a major inconvenience."
>>>>>
>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>>
>>>>>
>>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>>> brake. WW
>>>
>>> If I need to stop a spinning table saw blade in a hurry to change or
>>> reset something, I find that a scrap piece of lumber makes a great blade
>>> brake. Turn the saw off and slide the scrap up to the still spinning
>>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>>
>>
>> Someone could make some money by developing an aftermarket saw brake,
>> under the
>> table.... pads or rollers or whatever, that would squeeze the blade.
>
> I've always wondered if a set of good quality bicycle brakes couldn't be
> safely mounted on the trunnion to perform that very task. Route the cable
> to the front of the saw to a hand or foot operated lever and there ya go.
>
> --
> Free bad advice available here.
> To reply, eat the taco.
> http://www.flickr.com/photos/bbqboyee/
The now common disk brakes might be a great match - their designed to grab a
thin metal disk instead of a wide rim.
Kerry
Can we drink beer in court?
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
And Nikolai Yvanovich Lobachevski is his _name_ . . .
> Welllll, looks like I own someone a beer.
> Yeppers, I said, "...aftermarket saw brake, under the table.... pads or
> rollers or whatever, that would squeeze the blade," and then you brought
> up the bike brake.
>
For fast stops a powered brake on may be preferred to normally brake on with
a spring setting the speed and strength to be held open all the time.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Interesting. There is certainly a lot for force against a bike brake
than a coasting saw blade/motor. I think a simple spring and
electromagnet/solenoid would do the trick in the same way an electric
door bell works.
No electric current: spring holds brakes closed.
Electric current: solenoid pulls brakes open.
A manual cable or secondary electric source could be added for manual
brake release.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Wed, 13 Oct 2010 11:37:59 -0500, -MIKE- <[email protected]>
wrote:
>On 10/13/10 11:22 AM, Bill wrote:
>> -MIKE- wrote:
>>> On 10/13/10 7:44 AM, Markem wrote:
>>>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>>>> <[email protected]> wrote:
>>>>
>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>> my '76 Lincoln might surprise you.
>>>>
>>>> Yes but the heat will do what to the saw blade?
>>>>
>>>> Mark
>>>
>>> Nothing.
>>> A lot more heat is generated by cutting than would be generated in the
>>> half second it would take to slow down the blade.
>>>
>>> You guys do realize we're not leaving the motor on in this scenario,
>>> right? :-)
>>>
>>
>> Yep, thought of that. Gotta break the problem into parts (important
>> trick/secret!) : ) I didn't count the mass of the rotor either, or it's
>> attached parts, in my other post either. I'm curious now though about
>> the calculation (foot/lbs of force).
>>
>> Bill
>>
>
>Sometimes all it takes is a couple of scraps of wood to show how
>"little" force is needed. Haven't you ever stopped a coasting blade with
>a scrap of wood?
>
>I still see people talking about the SawStop and what it takes for an
>emergency stop of the blade. I don't know about anyone else, but all I'm
>talking about is a convenience stop.
>I suspect a blade could be stopped (at shut-off) in less that a second
>with something the size of a bicycle brake and a spring.
Use a DC motor and a DPDT switch with a big resistor across the "stop"
terminals to short the motor when you shut it off. Stop a 10 inch
blade from 3600rpm in less trha a second with a dead short (if the
switch can handle it) or in about 2 seconds with a good "soft" braking
resistor.
You must be a controls or P&C guy with WNH!
<[email protected]> wrote in message
news:[email protected]...
Use a DC motor and a DPDT switch with a big resistor across the "stop"
terminals to short the motor when you shut it off. Stop a 10 inch
blade from 3600rpm in less trha a second with a dead short (if the
switch can handle it) or in about 2 seconds with a good "soft" braking
resistor.
In article <[email protected]>,
[email protected] says...
>
> On Wed, 13 Oct 2010 11:37:59 -0500, -MIKE- <[email protected]>
> wrote:
>
> >On 10/13/10 11:22 AM, Bill wrote:
> >> -MIKE- wrote:
> >>> On 10/13/10 7:44 AM, Markem wrote:
> >>>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> >>>> <[email protected]> wrote:
> >>>>
> >>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>>>> my '76 Lincoln might surprise you.
> >>>>
> >>>> Yes but the heat will do what to the saw blade?
> >>>>
> >>>> Mark
> >>>
> >>> Nothing.
> >>> A lot more heat is generated by cutting than would be generated in the
> >>> half second it would take to slow down the blade.
> >>>
> >>> You guys do realize we're not leaving the motor on in this scenario,
> >>> right? :-)
> >>>
> >>
> >> Yep, thought of that. Gotta break the problem into parts (important
> >> trick/secret!) : ) I didn't count the mass of the rotor either, or it's
> >> attached parts, in my other post either. I'm curious now though about
> >> the calculation (foot/lbs of force).
> >>
> >> Bill
> >>
> >
> >Sometimes all it takes is a couple of scraps of wood to show how
> >"little" force is needed. Haven't you ever stopped a coasting blade with
> >a scrap of wood?
> >
> >I still see people talking about the SawStop and what it takes for an
> >emergency stop of the blade. I don't know about anyone else, but all I'm
> >talking about is a convenience stop.
> >I suspect a blade could be stopped (at shut-off) in less that a second
> >with something the size of a bicycle brake and a spring.
>
> Use a DC motor and a DPDT switch with a big resistor across the "stop"
> terminals to short the motor when you shut it off. Stop a 10 inch
> blade from 3600rpm in less trha a second with a dead short (if the
> switch can handle it) or in about 2 seconds with a good "soft" braking
> resistor.
Which is where this thread started.
On Oct 13, 12:49=A0pm, -MIKE- <[email protected]> wrote:
> On 10/13/10 11:30 AM, Bill wrote:
>
>
>
>
>
> > -MIKE- wrote:
> >> On 10/13/10 9:43 AM, J. Clarke wrote:
> >>> In article<[email protected]>, [email protected] says...
>
> >>>> J. Clarke wrote:
> >>>>> In article<[email protected]>, [email protected] says...
>
> >>>>>> J. Clarke wrote:
> >>>>>>> In article<[email protected]>,
> >>>>>>> [email protected] says...
>
> >>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>
> >>>>>>>>> J. Clarke wrote:
> >>>>>>>>>> In article<[email protected]>, [email protected]=
m
> >>>>>>>>>> says...
>
> >>>>>>>>>>> I would think that an emergency stop mechanism would be a
> >>>>>>>>>>> whole different
> >>>>>>>>>>> magnitude than a scheduled, everyday, stop.
>
> >>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
> >>>>>>>>>>> stop the blade
> >>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
> >>>>>>>>>>> blade rotations
> >>>>>>>>>>> would be OK too. These two situations would require different
> >>>>>>>>>>> tactics.
>
> >>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
> >>>>>>>>>>> two different
> >>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
> >>>>>>>>>>> caliper probably
> >>>>>>>>>>> wouldn't last long in everyday usage and would need to be
> >>>>>>>>>>> adjusted and/or
> >>>>>>>>>>> replaced frequently.
>
> >>>>>>>>>> So how much power do you have to put into that electronic brak=
e
> >>>>>>>>>> to stop
> >>>>>>>>>> the blade as fast as Sawstop's physical block?
>
> >>>>>>>>>> And why would a caliper not last long? A set of brake pads on =
a
> >>>>>>>>>> car
> >>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting =
a
> >>>>>>>>>> Hell of
> >>>>>>>>>> a lot more of a workout that they would stopping a little bitt=
y
> >>>>>>>>>> saw
> >>>>>>>>>> blade that masses less than 1/1000 as much.
>
> >>>>>>>>> The physics on that seem interesting. A little like stopping a
> >>>>>>>>> speeding
> >>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
> >>>>>>>>> quite as
> >>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
> >>>>>>>>> try that
> >>>>>>>>> either.
>
> >>>>>>>>> Bill
> >>>>>>>> No way a caliper could stop the blade in even 4X the time the
> >>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad"
> >>>>>>>> and
> >>>>>>>> the blade would be quite problematic - with dust decreasing the
> >>>>>>>> stopping efficiency by a very large margin.
>
> >>>>>>> I suspect that a small pyrotechnic pressurizing one of the
> >>>>>>> calipers off
> >>>>>>> my '76 Lincoln might surprise you.
>
> >>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know =
for
> >>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>
> >>>>> Why would something that can stop a 4000 pound car "snap" when
> >>>>> called on
> >>>>> to stop a 3 pound saw blade?
>
> >>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>
> >>> To stop the saw in a fraction of a revolution, you need rapid
> >>> application. A pyro will build pressure rapidly.
>
> >> I didn't think we were talking about an emergency stop.
> >> AFAIK, we're discussing a convenience stop which, in my opinion, would
> >> be satisfactorily done in a couple seconds, not milliseconds.
>
> > I thought we were discussing a stop on the same order as SawStop.
> > I didn't read every post in the thread.
>
> > Bill
>
> Someone brought SawStop into the discussion, which took things on a
> tangent.
> We started out discussing the OP's link to a set of motor reversing
> instructions as a way to slow down the blade for convenience. Then I
> proposed the use of a bicycle brake... and things went from there.
>
> --
>
> =A0 -MIKE-
>
> =A0 "Playing is not something I do at night, it's my function in life"
> =A0 =A0 =A0--Elvin Jones =A0(1927-2004)
> =A0 --
> =A0http://mikedrums.com
> =A0 [email protected]
> =A0 ---remove "DOT" ^^^^ to reply
A thread getting knocked off the rails here in the Wreck.... imagine
my surprise...LOL
On Sun, 10 Oct 2010 21:41:24 -0500, -MIKE- <[email protected]>
wrote:
>On 10/10/10 9:22 PM, Larry Jaques wrote:
>> WTF does that have to do with lawsuits? People sue to keep their
>> product on top whether they have a case or not. REAL WORLD, Mike.
>>
>
>In the "REAL WORLD" (relax, man), patent infringement law suits get
>thrown out in the first hearing, too, Larry. What, you're a patent
>attorney, too?
No, I've just been horrified at how many frivolous lawsuits make it
into court, including patent infringement suits. Check it out.
--
Ask not what the world needs. Ask what makes you come
alive... then go do it. Because what the world needs
is people who have come alive. -- Howard Thurman
I would think that an emergency stop mechanism would be a whole different
magnitude than a scheduled, everyday, stop.
For a finger saver an emergency stop mechanism would have to stop the blade
in a few teeth passings. For everyday usage a couple dozen blade rotations
would be OK too. These two situations would require different tactics.
A dynamic electronic brake could vary the intensity for the two different
scenarios and we could add the caliper to the emerg stop. A caliper probably
wouldn't last long in everyday usage and would need to be adjusted and/or
replaced frequently.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
I would prefer powered off/normal on, because the operator would get
used to the blade always braking and in the case of a solenoid failure,
the blade would not coast.
I would also think an assembly with wheels applying just a little
pressure to the sides of the blade would make a decent passive system.
It would be just enough pressure to slow down the blade in a second or
two and not enough pressure for the motor to even register the resistance.
Think about how little pressure it takes with a scrap piece of wood to
stop a coasting blade.
--
On 10/10/10 10:34 PM, Josepi wrote:
> For fast stops a powered brake on may be preferred to normally brake on
> with
> a spring setting the speed and strength to be held open all the time.
>
In article <[email protected]>,
[email protected] says...
>
> On Wed, 13 Oct 2010 23:16:27 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>, [email protected]
> >says...
> >>
> >> As I stated posters seem to lean towards the technology they are comfortable
> >> with.
> >>
> >> The mechanics would be a nightmare to me, also. To others the electronics
> >> would be a nightmare.
> >>
> >> Contactor and resistor?...way too complicated.
> >
> >So tell us how to wire an induction motor to make the "contactor and
> >resistor" work.
> On an induction motor the process is a bit different. Instead of a
> resistor across the motor to stop it you use "DC Injection" - in other
> words throw about 40 volts DC across the winding for about 2 seconds.
So now you have to add a power supply and controls.
On Wed, 13 Oct 2010 23:16:27 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>, [email protected]
>says...
>>
>> As I stated posters seem to lean towards the technology they are comfortable
>> with.
>>
>> The mechanics would be a nightmare to me, also. To others the electronics
>> would be a nightmare.
>>
>> Contactor and resistor?...way too complicated.
>
>So tell us how to wire an induction motor to make the "contactor and
>resistor" work.
On an induction motor the process is a bit different. Instead of a
resistor across the motor to stop it you use "DC Injection" - in other
words throw about 40 volts DC across the winding for about 2 seconds.
Maybe not. Somebody has to take one for the team. Induction motors typically
have enough back emf generation to cause some, if not enough braking to stop
most motors.
Somebody try it. With the saw blade running full speed, pull the plug (do
**NOT** turn off the switch) and stick the two plug contacts (line and
neutral) across the metal table top and short it out.
Tell us what happens and what kind of motor you have.
The DC injection will involve a little more circuitry.
I have experienced both with different motors. They ranged from 1hp AC to
5hp DC units. The DC injection could make them stop in a turn or so but with
such large motors the torque was brutal.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
So now you have to add a power supply and controls.
In article <[email protected]>,
[email protected] says...
On an induction motor the process is a bit different. Instead of aresistor
across the motor to stop it you use "DC Injection" - in other
words throw about 40 volts DC across the winding for about 2 seconds.
On Wed, 13 Oct 2010 19:22:05 -0400, "Josepi" <[email protected]>
wrote:
>You must be a controls or P&C guy with WNH!
>
>
><[email protected]> wrote in message
>news:[email protected]...
>Use a DC motor and a DPDT switch with a big resistor across the "stop"
>terminals to short the motor when you shut it off. Stop a 10 inch
>blade from 3600rpm in less trha a second with a dead short (if the
>switch can handle it) or in about 2 seconds with a good "soft" braking
>resistor.
>
Nope, just an ex-mechanic wire-head.
On Sat, 09 Oct 2010 12:47:25 +0100, Stuart <[email protected]>
wrote:
>In article <[email protected]>,
> HeyBub <[email protected]> wrote:
>> I was looking for a home remedy for a festering, fulminating, giant red
>> mass on my, er, never mind.
>
>A boil on the bum then :-)
Sounded like election-time talk to me. <shrug>
--
Ask not what the world needs. Ask what makes you come
alive... then go do it. Because what the world needs
is people who have come alive. -- Howard Thurman
On 10/10/10 11:35 AM, willshak wrote:
> WW wrote the following:
>> "HeyBub" <[email protected]> wrote in message
>> news:[email protected]...
>>> Found this article...
>>>
>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>> in the home workshop. Stationary grinders, table and radial arm
>>> circular saws frequently turn abrasive or cutting disks that are
>>> directly mounted on the motor's spindle. These disks have large
>>> inertial moments that allow them to free wheel for a long time after
>>> the power is turned off. A lengthy coast to complete stop often
>>> amounts to a major inconvenience."
>>>
>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>
>>>
>>> Great ... I may rig up my table saw this way. Would be safer with a
>>> brake. WW
>
> If I need to stop a spinning table saw blade in a hurry to change or
> reset something, I find that a scrap piece of lumber makes a great blade
> brake. Turn the saw off and slide the scrap up to the still spinning
> blade. Blade stops in a couple of seconds. No extra parts needed.
>
Someone could make some money by developing an aftermarket saw brake,
under the table.... pads or rollers or whatever, that would squeeze the
blade.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/10/10 4:51 PM, Larry Jaques wrote:
> On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE-<[email protected]>
> wrote:
>
>> On 10/10/10 11:35 AM, willshak wrote:
>>> WW wrote the following:
>>>> "HeyBub"<[email protected]> wrote in message
>>>> news:[email protected]...
>>>>> Found this article...
>>>>>
>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>>> in the home workshop. Stationary grinders, table and radial arm
>>>>> circular saws frequently turn abrasive or cutting disks that are
>>>>> directly mounted on the motor's spindle. These disks have large
>>>>> inertial moments that allow them to free wheel for a long time after
>>>>> the power is turned off. A lengthy coast to complete stop often
>>>>> amounts to a major inconvenience."
>>>>>
>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>>
>>>>>
>>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>>> brake. WW
>>>
>>> If I need to stop a spinning table saw blade in a hurry to change or
>>> reset something, I find that a scrap piece of lumber makes a great blade
>>> brake. Turn the saw off and slide the scrap up to the still spinning
>>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>>
>>
>> Someone could make some money by developing an aftermarket saw brake,
>> under the table.... pads or rollers or whatever, that would squeeze the
>> blade.
>
> Lawsuits from the arse with the SawStop patents notwithstanding, I
> think he went with the positive stop style because it's the only one
> which would keep from taking a finger off. The rest spin just enough
> to do serious damage.
>
A saw blade brake wouldn't infringe on SawStop's patent at all.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/10/2010 11:54 AM, -MIKE- wrote:
> On 10/10/10 11:35 AM, willshak wrote:
>> WW wrote the following:
>>> "HeyBub" <[email protected]> wrote in message
>>> news:[email protected]...
>>>> Found this article...
>>>>
>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>> in the home workshop. Stationary grinders, table and radial arm
>>>> circular saws frequently turn abrasive or cutting disks that are
>>>> directly mounted on the motor's spindle. These disks have large
>>>> inertial moments that allow them to free wheel for a long time after
>>>> the power is turned off. A lengthy coast to complete stop often
>>>> amounts to a major inconvenience."
>>>>
>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>
>>>>
>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>> brake. WW
>>
>> If I need to stop a spinning table saw blade in a hurry to change or
>> reset something, I find that a scrap piece of lumber makes a great blade
>> brake. Turn the saw off and slide the scrap up to the still spinning
>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>
>
> Someone could make some money by developing an aftermarket saw brake, under the
> table.... pads or rollers or whatever, that would squeeze the blade.
I've always wondered if a set of good quality bicycle brakes couldn't be safely
mounted on the trunnion to perform that very task. Route the cable to the
front of the saw to a hand or foot operated lever and there ya go.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/10/10 7:51 PM, Steve Turner wrote:
>> Someone could make some money by developing an aftermarket saw brake,
>> under the
>> table.... pads or rollers or whatever, that would squeeze the blade.
>
> I've always wondered if a set of good quality bicycle brakes couldn't be
> safely mounted on the trunnion to perform that very task. Route the
> cable to the front of the saw to a hand or foot operated lever and there
> ya go.
>
Interesting. There is certainly a lot for force against a bike brake
than a coasting saw blade/motor. I think a simple spring and
electromagnet/solenoid would do the trick in the same way an electric
door bell works.
No electric current: spring holds brakes closed.
Electric current: solenoid pulls brakes open.
A manual cable or secondary electric source could be added for manual
brake release.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
[email protected] wrote:
>>
>> Why would it be "impractical on a 10" saw? The brake rotors on that
>> car are IIRC 11.5 inch diameter and the whole brake assembly fits
>> inside a 15" wheel.
>>
> You want to put that monstrosity on a tilting arbour saw, mounted
> under the saw table and in the path of the saw-dust and have it work
> reliably???
> Not going to happen - guaranteed.
You want to put that goober under a car where it has to contend with dirt,
water, oil, ice, salt, road-kill entrails, and have it work reliably???
Common sense says it won't work and can't be made to work. Don't believe
your lyin' eyes.
As I stated posters seem to lean towards the technology they are comfortable
with.
The mechanics would be a nightmare to me, also. To others the electronics
would be a nightmare.
Contactor and resistor?...way too complicated.
<[email protected]> wrote in message
news:[email protected]...
You want to put that monstrosity on a tilting arbour saw, mounted
under the saw table and in the path of the saw-dust and have it work
reliably???
Not going to happen - guaranteed.
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 22:29:51 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Fri, 15 Oct 2010 23:50:50 +0100, Stuart <[email protected]>
> >> wrote:
> >>
> >> >In article <[email protected]>,
> >> > <[email protected]> wrote:
> >> >
> >> >> That's my point. Nobody else, so far, has addressed how they would
> >> >> control the application of this "convenience brake", however
> >> >> implemented. My pushbutton solution was rejected out of hand - but how
> >> >> would any of the other suggested possibilities be implemented???
> >> >
> >> >OK, here goes:
> >> >
> >> >Pair of AC solenoids, one each side of the blade holding a brake pad away
> >> >from the blade, paralleled with feed to motor. When motor is powered
> >> >brakes are off, when motor switched off solenoids de-energise and springs
> >> >press pads against sides of blade. This is a "convenience" brake, no need
> >> >for great forces to be applied. Solenoids mounted on a sliding
> >> >arrangement, operated by a lever, which allows them to be moved out of the
> >> >way for blade changing.
> >> That would work - assuming there is space to mount it and the
> >> associated bracketry. Mechanically still more complex and therefore
> >> prone to failure.
> >>
> >> Generally speaking, an electronic implementation/solution is at least
> >> twice as reliable as a mechanical solution, and the difference
> >> increases as the mechanical complexity increases. More moving parts
> >> means more to fail.
> >
> >And that is why all cars have electronic brakes . . .
> >
> No. but the antilock system is electronic - and it COULD be
> mechanical.
My Lincoln has mechanical antiskid. Electronic is cheaper.
> RR, I believe, had a driveshaft powered hydraulic booster
> that reduced braking pressure when the rear wheels locked. The
> electronics are more reliable. Same with fuel injection and adjustable
> suspension.
So how do you make a mechanical system that can consider oxygen levels
in the exhaust.
On Fri, 15 Oct 2010 23:26:53 -0500, Steve Turner
<[email protected]> wrote:
>On 10/15/2010 8:34 PM, [email protected] wrote:
>> On Fri, 15 Oct 2010 16:34:51 -0500, Steve Turner
>> <[email protected]> wrote:
>>
>>> On 10/15/2010 1:16 PM, [email protected] wrote:
>>>> It is the only virtually universally implementable retrofit or add-on
>>>> solution that does not require custom engineering for every saw it
>>>> might possibly be applicable to.
>>>>
>>>> A lot of dreamers on the wreck - but how many implementers?
>>>
>>> I have every confidence that I can implement a mechanical solution on my
>>> Unisaw, and believe me, the naysayer attitude of a certain few (ahem) has just
>>> about ticked me off enough to follow through with it. My only problem is
>>> carving out the time to get it done; I have precious little of that these days.
>>>
>>> So what's stopping YOU from being an implementer?
>>
>> Absulutely nothing.
>> If I feel I need or want something, or some feature on something I
>> already have, I figure out how to do it and do it.
>> I decided I wanted an electric car - I built it.
>> When I was a kid I wanted a stereo record player - I built it.
>> I decided 10 years ago I wanted to fly - so I'm building an airplane -
>> and not from a kit - from plans.
>> I saw a "rhodes car" and figured I could build it better and lighter
>> for a lot less, so I built it.
>> Same with a tandem bike.
>
>Good on you. So then when can I expect your implementation of an electronic
>brake for my Unisaw? :-)
If I had a unisaw I'd likely have it implemented by now - but I
don't.
On Fri, 15 Oct 2010 22:29:51 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Fri, 15 Oct 2010 23:50:50 +0100, Stuart <[email protected]>
>> wrote:
>>
>> >In article <[email protected]>,
>> > <[email protected]> wrote:
>> >
>> >> That's my point. Nobody else, so far, has addressed how they would
>> >> control the application of this "convenience brake", however
>> >> implemented. My pushbutton solution was rejected out of hand - but how
>> >> would any of the other suggested possibilities be implemented???
>> >
>> >OK, here goes:
>> >
>> >Pair of AC solenoids, one each side of the blade holding a brake pad away
>> >from the blade, paralleled with feed to motor. When motor is powered
>> >brakes are off, when motor switched off solenoids de-energise and springs
>> >press pads against sides of blade. This is a "convenience" brake, no need
>> >for great forces to be applied. Solenoids mounted on a sliding
>> >arrangement, operated by a lever, which allows them to be moved out of the
>> >way for blade changing.
>> That would work - assuming there is space to mount it and the
>> associated bracketry. Mechanically still more complex and therefore
>> prone to failure.
>>
>> Generally speaking, an electronic implementation/solution is at least
>> twice as reliable as a mechanical solution, and the difference
>> increases as the mechanical complexity increases. More moving parts
>> means more to fail.
>
>And that is why all cars have electronic brakes . . .
>
No. but the antilock system is electronic - and it COULD be
mechanical. RR, I believe, had a driveshaft powered hydraulic booster
that reduced braking pressure when the rear wheels locked. The
electronics are more reliable. Same with fuel injection and adjustable
suspension.
ADHD acting up again, hopper?
Reading comprehension skills a little off?
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
Only a top-posting moron like you would claim that Outlook Express is a
superior news reader. YOU and your stupid news reader are always taking a
perfectly good forward-reading conversation and turning it completely
backwards, and when YOUR actions cause somebody else to misinterpret the
flow
and content of the conversation (what a surprise) YOU blame it on THEIR
newsreader.
> No big deal. Text mediums get messy after a while.
Yeah, because of idiots like you.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
Josepi wrote:
>
> A car brake is designed to avoid locking up, yet that's exactly the
> behavior you would want with a sawblade, and you'd want it to lock in
> much less than a single revolution.
ABS is designed to prevent lock up - car brakes are not.
--
-Mike-
[email protected]
On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>> >>
>> >> >J. Clarke wrote:
>> >> >> In article<[email protected]>, [email protected] says...
>> >> >>>
>> >> >>> I would think that an emergency stop mechanism would be a whole different
>> >> >>> magnitude than a scheduled, everyday, stop.
>> >> >>>
>> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
>> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> >> >>> would be OK too. These two situations would require different tactics.
>> >> >>>
>> >> >>> A dynamic electronic brake could vary the intensity for the two different
>> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> >> >>> replaced frequently.
>> >> >>
>> >> >> So how much power do you have to put into that electronic brake to stop
>> >> >> the blade as fast as Sawstop's physical block?
>> >> >>
>> >> >> And why would a caliper not last long? A set of brake pads on a car
>> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> >> >> a lot more of a workout that they would stopping a little bitty saw
>> >> >> blade that masses less than 1/1000 as much.
>> >> >
>> >> >The physics on that seem interesting. A little like stopping a speeding
>> >> >bullet on a dime--it challenges my imagination. Probably not quite as
>> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
>> >> >either.
>> >> >
>> >> >Bill
>> >> No way a caliper could stop the blade in even 4X the time the
>> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> >> the blade would be quite problematic - with dust decreasing the
>> >> stopping efficiency by a very large margin.
>> >
>> >I suspect that a small pyrotechnic pressurizing one of the calipers off
>> >my '76 Lincoln might surprise you.
>> >
>> But would also be totally impractical on a 10" saw.
>
>Why would it be "impractical on a 10" saw? The brake rotors on that car
>are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
>15" wheel.
>
You want to put that monstrosity on a tilting arbour saw, mounted
under the saw table and in the path of the saw-dust and have it work
reliably???
Not going to happen - guaranteed.
[email protected] wrote:
> On Thu, 14 Oct 2010 22:18:51 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> [email protected] wrote:
>>
>>>
>>> Never see the black staining in oak from non-galvanized nails? That
>>> is due to corrosion. Doesn't take much corrosion to make a caliper
>>> just fussy enough that it might not do the required job (for which
>>> it was not designed).
>>>
>>
>> I thought you worked on cars Clare. Have you ever seen a caliper
>> that was *not corroded*? You're exagerating things in attempt to
>> bolster your point but again, it's just not true.
> The outer frame of the caliper can be corroded all to heck - no
> problem. If the slider mechanism is corroded (which it often is)
> braking is less linear, and less predictable. They can (and do) drag.
> They can also apply late.
>
> If the piston gets corroded, all the same, but a lot worse.
You are thinking of car brakes and not of calipers in general. That said -
every piece of metal on a car caliper assembly corrodes, yet they continue
to work until the corrosion on the slide becomes excessive. Not something a
table saw would likely see. I agree that with a corroded slider, braking is
less linear, but again, a table saw would not even require a slider, so the
direct comparison to a car caliper need not be made. Calipers exist outside
of the world of automobiles and calipers could make a perfectly acceptable
solution (one of many options) for a table saw. No one has suggested a car
caliper for a table saw, but instead has compared a comparatively hostile
environment where one type of caliper has proven itself.
--
-Mike-
[email protected]
On Sun, 17 Oct 2010 23:41:18 -0400, "Mike Marlow"
<[email protected]> wrote:
>Larry Jaques wrote:
>> On Sat, 16 Oct 2010 21:29:05 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> Larry Jaques wrote:
>>>
>>>>
>>>> I heartily disagree. The only solid ever thrown up at a brake
>>>> caliper in any quantity is water, and that runs right off. Sawdust
>>>> would tend to stick, especially in the inverted configuration it
>>>> would have on a table saw. 'Twould be especially bad with folks who
>>>> "do Jummywood."
>>>>
>>>> Go ahead and prove me wrong, Mike. Mount one and see. I double dare
>>>> ya!
>>>
>>> I'm a sucker for a dare. Damnit... I agree the sawdust would
>>> stick, but I don't think that would be a real problem. It would be
>>> worn off the braking surface rather easily.
>>
>> Just in time for a sawdust fire! Oops.
>
>You arse - now you're changing the direction of this thread. We'll have to
>labor through fire hazards, fire extinuishers, and smoke detectors now....
...Regulators, insurances, etc...
Life's a bitch and then you die, so go suffer quietly among the
madding crowd, Mikey. _I'm_ otherwise occupied.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 09:32:43 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
> >> <[email protected]> wrote:
> >>
> >> >On 10/14/2010 2:52 PM, [email protected] wrote:
> >> >> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
> >> >> <[email protected]> wrote:
> >> >>
> >> >>> Larry Jaques wrote:
> >> >>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
> >> >>>> <[email protected]> wrote:
> >> >>>
> >> >>>>>
> >> >>>>> As a guy who has done all of his own vehicle maintenance for 40
> >> >>>>> years now, I have to ask what you observed in your experiences, that
> >> >>>>> causes you to make this statement? I don't know if the brake
> >> >>>>> caliper idea is the most elegant solution, but I sure can't see
> >> >>>>> anything in what you are saying that would suggest it is not a
> >> >>>>> workable solution.
> >> >>>>
> >> >>>> Suitable placement of an air nozzle tube to clear the caliper frame
> >> >>>> every hour or so would go far into making this device work for more
> >> >>>> than an hour. You'd have to keep the sawdust from piercing the seals
> >> >>>> and/or building up on the frame
> >> >>>
> >> >>> Not at all Larry, if you consider what a normal brake caliper in an
> >> >>> automobile is subject to. In comparison, the environment inside a table saw
> >> >>> would be a walk in the part of a caliper.
> >> >>
> >> >>
> >> >> You get a splinter of oak thrown at a rubber caliper boot at 18000
> >> >> feet per minute (almost 205MPH) a few times and expect the boot to
> >> >> survive?. For the brake to see the same rotational RPM on a car with
> >> >> 24" diameter tires (pretty standard today) you would need to drive
> >> >> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
> >> >>
> >> >> A 10" saw runs closer to 5200 RPM - so 370 MPH.
> >> >
> >> >Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
> >> >would be even more impossible to stop.
> >> >
> >>
> >> No, I said nothing of the sort. I didn't even say anything about it
> >> being hard to stop. I was comaring the speed at which particals might
> >> possibly hit the boot on the lincoln caliper some dufus was talking
> >> about mounting to the table saw to stop the blade, The speed at which
> >> a sliver could be flung at that boot from a typical table saw blade
> >> would require the above mentioned speeds with the caliper on a car -
> >> assuming the bit was picked up from the road or thrown from the
> >> circumference of the tire.
> >> >> Also, the caliper is actually pretty well protected mounted as it is
> >> >> virtually inside the wheel - with the caliper boot protected between
> >> >> the pad and tha caliper frame, and usually behind a splash shield as
> >> >> well.
> >> >>
> >> >> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> >> >> onto every surface of the caliper.
> >> >
> >> >Geez Chicken Little, how many mountains are you going to make out of molehills
> >> >on this topic? Just about every point you've tried to make has had the air of
> >> >doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
> >>
> >> Nobody said it was difficult. Just saying the brake from the old
> >> lincoln is NOT going to be anywhere close to an effective solution.
> >> So many guys on the Wreck just make things WAY too complicated.
> >>
> >> You want a convenience brake on an AC table saw? DC injection braking
> >> is as simple as it gets and can be done by a reasonably adept
> >> scrounger for less than $25 in less than an hour, with NO
> >> modifications to the physical part of the saw. Just grabbing a few
> >> parts out of my scrap bin I could have it working on a saw in less
> >> than half an hour with no cash outlay at all. Not fully automated -
> >> but hit the stop button or turn off the power and press a pushbutton
> >> untill the blade stops (about 2 seconds) using nothing more than an
> >> old PC power supply and a pushbutton switch. To make it a littlemore
> >> foolproof the power switch would need to be replaces with a SPDT or
> >> DPDT switch or augmented by a relay to prevent injecting the DC while
> >> the AC was still connected.
> >
> >But if I have to push a button to stop the blade I may as well just
> >shove a pushstick into the side of it.
> >
> Which is why using the DPDT switch makes it foolproof. and simple
> circuitry can handle the injection current timing.
So where can I buy a DPDT switch with a big red "off" button that I can
hit with my knee?
On 10/15/2010 8:34 PM, [email protected] wrote:
> On Fri, 15 Oct 2010 16:34:51 -0500, Steve Turner
> <[email protected]> wrote:
>
>> On 10/15/2010 1:16 PM, [email protected] wrote:
>>> It is the only virtually universally implementable retrofit or add-on
>>> solution that does not require custom engineering for every saw it
>>> might possibly be applicable to.
>>>
>>> A lot of dreamers on the wreck - but how many implementers?
>>
>> I have every confidence that I can implement a mechanical solution on my
>> Unisaw, and believe me, the naysayer attitude of a certain few (ahem) has just
>> about ticked me off enough to follow through with it. My only problem is
>> carving out the time to get it done; I have precious little of that these days.
>>
>> So what's stopping YOU from being an implementer?
>
> Absulutely nothing.
> If I feel I need or want something, or some feature on something I
> already have, I figure out how to do it and do it.
> I decided I wanted an electric car - I built it.
> When I was a kid I wanted a stereo record player - I built it.
> I decided 10 years ago I wanted to fly - so I'm building an airplane -
> and not from a kit - from plans.
> I saw a "rhodes car" and figured I could build it better and lighter
> for a lot less, so I built it.
> Same with a tandem bike.
Good on you. So then when can I expect your implementation of an electronic
brake for my Unisaw? :-)
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On Fri, 15 Oct 2010 09:32:43 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
>> <[email protected]> wrote:
>>
>> >On 10/14/2010 2:52 PM, [email protected] wrote:
>> >> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
>> >> <[email protected]> wrote:
>> >>
>> >>> Larry Jaques wrote:
>> >>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>> >>>> <[email protected]> wrote:
>> >>>
>> >>>>>
>> >>>>> As a guy who has done all of his own vehicle maintenance for 40
>> >>>>> years now, I have to ask what you observed in your experiences, that
>> >>>>> causes you to make this statement? I don't know if the brake
>> >>>>> caliper idea is the most elegant solution, but I sure can't see
>> >>>>> anything in what you are saying that would suggest it is not a
>> >>>>> workable solution.
>> >>>>
>> >>>> Suitable placement of an air nozzle tube to clear the caliper frame
>> >>>> every hour or so would go far into making this device work for more
>> >>>> than an hour. You'd have to keep the sawdust from piercing the seals
>> >>>> and/or building up on the frame
>> >>>
>> >>> Not at all Larry, if you consider what a normal brake caliper in an
>> >>> automobile is subject to. In comparison, the environment inside a table saw
>> >>> would be a walk in the part of a caliper.
>> >>
>> >>
>> >> You get a splinter of oak thrown at a rubber caliper boot at 18000
>> >> feet per minute (almost 205MPH) a few times and expect the boot to
>> >> survive?. For the brake to see the same rotational RPM on a car with
>> >> 24" diameter tires (pretty standard today) you would need to drive
>> >> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
>> >>
>> >> A 10" saw runs closer to 5200 RPM - so 370 MPH.
>> >
>> >Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
>> >would be even more impossible to stop.
>> >
>>
>> No, I said nothing of the sort. I didn't even say anything about it
>> being hard to stop. I was comaring the speed at which particals might
>> possibly hit the boot on the lincoln caliper some dufus was talking
>> about mounting to the table saw to stop the blade, The speed at which
>> a sliver could be flung at that boot from a typical table saw blade
>> would require the above mentioned speeds with the caliper on a car -
>> assuming the bit was picked up from the road or thrown from the
>> circumference of the tire.
>> >> Also, the caliper is actually pretty well protected mounted as it is
>> >> virtually inside the wheel - with the caliper boot protected between
>> >> the pad and tha caliper frame, and usually behind a splash shield as
>> >> well.
>> >>
>> >> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>> >> onto every surface of the caliper.
>> >
>> >Geez Chicken Little, how many mountains are you going to make out of molehills
>> >on this topic? Just about every point you've tried to make has had the air of
>> >doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
>>
>> Nobody said it was difficult. Just saying the brake from the old
>> lincoln is NOT going to be anywhere close to an effective solution.
>> So many guys on the Wreck just make things WAY too complicated.
>>
>> You want a convenience brake on an AC table saw? DC injection braking
>> is as simple as it gets and can be done by a reasonably adept
>> scrounger for less than $25 in less than an hour, with NO
>> modifications to the physical part of the saw. Just grabbing a few
>> parts out of my scrap bin I could have it working on a saw in less
>> than half an hour with no cash outlay at all. Not fully automated -
>> but hit the stop button or turn off the power and press a pushbutton
>> untill the blade stops (about 2 seconds) using nothing more than an
>> old PC power supply and a pushbutton switch. To make it a littlemore
>> foolproof the power switch would need to be replaces with a SPDT or
>> DPDT switch or augmented by a relay to prevent injecting the DC while
>> the AC was still connected.
>
>But if I have to push a button to stop the blade I may as well just
>shove a pushstick into the side of it.
>
Which is why using the DPDT switch makes it foolproof. and simple
circuitry can handle the injection current timing.
On Fri, 15 Oct 2010 16:34:51 -0500, Steve Turner
<[email protected]> wrote:
>On 10/15/2010 1:16 PM, [email protected] wrote:
>> OK - the whole premise of using a caliper, regardless of the source
>> of the caliper, for a retrofit to an existing saw has all the
>> drawbacks I have stated. OK, the corrosion might be a bit overstated -
>> but it IS an issue that would have to be dealt with -nas it has to be
>> dealt with in automotive, bicycle, and motorcycle applications. Using
>> a caliper of any sort on the blade, even on a purpose built clean
>> sheet saw design has engineering problems that would be best avoided
>> due to complexity (like blade changing, adjustment for dado use, etc.)
>> Putting the caliper (or drum) on the opposite end of the arbour
>> handles most of those issues, but again, on a clean sheet design. As a
>> retrofit it is still problematic.
>
>That's a blanket statement. I would say that depends on the saw.
>
>> Putting the brake on the motor is
>> the simplest solution - wheather mechanical or electrical, and
>> wheather direct drive or belt drive.
>
>That's what I concluded after inspecting my saw (the Unisaw). Other saws may
>be different.
>
>> Either way, electrical application is the simplest, cheapest
>> alternative (compared to hydraulic, mechanical, pneumatic, or
>> percussive application) - and if you are going to use electical or
>> electronic controls anyway, why not use electrical braking all the
>> way?
>
>In my case, it's because I can understand and implement mechanical devices;
>electrical, not so much. If somebody were to implement and test and guarantee
>an electrical braking system that could be retrofitted to my Unisaw I would
>certainly be interested.
>
>> That's my point. Nobody else, so far, has addressed how they would
>> control the application of this "convenience brake", however
>> implemented. My pushbutton solution was rejected out of hand - but how
>> would any of the other suggested possibilities be implemented???
>
>I don't recall rejecting yours, I only recall you rejecting mine... In any
>case, for the Unisaw I think it would be relatively simple to actuate the brake
>with a mechanical lever that's mounted in front of the power-off switch.
>Initial pressure on the lever would actuate the power-off switch and cut power
>to the motor, additional pressure would actuate the brake. This is exactly the
>way the mechanical (automotive style drum) brake on my MiniMax bandsaw works.
>And work it does; like a dream, and I can tell you that those upper and lower
>drive wheels are about 20lbs apiece and have WAY (*WAY*!) more mass and
>centrifugal force than a free-spinning table saw blade assembly.
>
>> It is the only virtually universally implementable retrofit or add-on
>> solution that does not require custom engineering for every saw it
>> might possibly be applicable to.
>>
>> A lot of dreamers on the wreck - but how many implementers?
>
>I have every confidence that I can implement a mechanical solution on my
>Unisaw, and believe me, the naysayer attitude of a certain few (ahem) has just
>about ticked me off enough to follow through with it. My only problem is
>carving out the time to get it done; I have precious little of that these days.
>
>So what's stopping YOU from being an implementer?
Absulutely nothing.
If I feel I need or want something, or some feature on something I
already have, I figure out how to do it and do it.
I decided I wanted an electric car - I built it.
When I was a kid I wanted a stereo record player - I built it.
I decided 10 years ago I wanted to fly - so I'm building an airplane -
and not from a kit - from plans.
I saw a "rhodes car" and figured I could build it better and lighter
for a lot less, so I built it.
Same with a tandem bike.
>
>> Also, if electrical convenience braking is such a bad idea, why is it
>> virtually the ONLY method used on commercially available table saws,
>> particularly in the "consumer grade", "contractor", or "semi-pro"
>> lines?
>
>You never heard from *me* that it was a bad idea.
>
>> Virtually every hand held circular saw on the market today has a
>> "dynamic blade brake" as a standard feature as well.
>> So does virtually every quality cut-off or miter saw.
>
>My 3HP Makita plunge router has one and I love it. So does my Delta chop saw,
>but that thing's a piece of crap in most every other respect, so I avoid using
>it unless I have to.
>
>> Best of all, it COULD be made as a simple plug-in module that you plug
>> the saw into - replacing the existing power switch, on all but the
>> higher end saws that use contactors instead of a simple switch.
>>
>> It could be made offshore, in reasonable quantities, to sell for less
>> than $50 retail.
>> It could be implemented, from scratch, by a reasonably competent
>> tinkerer for under $100 buying all the parts new from local or online
>> sources, and could be installed on ANY saw. Either as a plug in as
>> above, or wired directly into the saw. Contacter controlled mabee add
>> another $50.
>
>I would have zero confidence in doing that unless I was working from plans
>offered by another "tinkerer" who had already succeeded and was able to
>demonstrate that it worked and was safe and that it wouldn't electrocute me or
>destroy my saw. :-)
>
>> Again - we are talking convenience brake - not emergency stop
>
>Yep.
On Thu, 14 Oct 2010 22:18:51 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>
>>
>> Never see the black staining in oak from non-galvanized nails? That is
>> due to corrosion. Doesn't take much corrosion to make a caliper just
>> fussy enough that it might not do the required job (for which it was
>> not designed).
>>
>
>I thought you worked on cars Clare. Have you ever seen a caliper that was
>*not corroded*? You're exagerating things in attempt to bolster your point
>but again, it's just not true.
The outer frame of the caliper can be corroded all to heck - no
problem. If the slider mechanism is corroded (which it often is)
braking is less linear, and less predictable. They can (and do) drag.
They can also apply late.
If the piston gets corroded, all the same, but a lot worse.
In article <[email protected]>,
Scott Lurndal <[email protected]> wrote:
> A car wheel spinning at 5000RPM's isn't stopped within a single rotation
> by a caliper disc brake.
If a car wheel has a rolling diameter of, say, 17", the car will travel about
4.45 feet per revolution. 5000rpm means the car will be travelling at
22,251 ft/min or 252mph. I'm not surprised given the car probably weighs
upwards of a ton.
However, as anyone who has done much driving before the advent of ABS will
tell you, it is quite easy to lock up the wheels of a car if you stamp on
the brake hard enough.
> Why would you expect a saw blade to be?
Because the energy in a rotating saw blade is bugger all compared with a
moving car.
Josepi wrote:
> Should have read. (I didn't write the attributed text)
>
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> ABS is designed to prevent lock up - car brakes are not.
Not sure what you are trying to point out. I did a simple reply all. The
problems come in when people like yourself insist on replying in a manner
that defies normal attributions. Really do not understand what your
statement "Should have read" means.
--
-Mike-
[email protected]
In article <[email protected]>,
[email protected] says...
>
> On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> >> <[email protected]> wrote:
> >>
> >> >In article <[email protected]>,
> >> >[email protected] says...
> >> >>
> >> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
> >> >>
> >> >> >J. Clarke wrote:
> >> >> >> In article<[email protected]>, [email protected] says...
> >> >> >>>
> >> >> >>> I would think that an emergency stop mechanism would be a whole different
> >> >> >>> magnitude than a scheduled, everyday, stop.
> >> >> >>>
> >> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
> >> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >> >> >>> would be OK too. These two situations would require different tactics.
> >> >> >>>
> >> >> >>> A dynamic electronic brake could vary the intensity for the two different
> >> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >> >> >>> replaced frequently.
> >> >> >>
> >> >> >> So how much power do you have to put into that electronic brake to stop
> >> >> >> the blade as fast as Sawstop's physical block?
> >> >> >>
> >> >> >> And why would a caliper not last long? A set of brake pads on a car
> >> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >> >> >> a lot more of a workout that they would stopping a little bitty saw
> >> >> >> blade that masses less than 1/1000 as much.
> >> >> >
> >> >> >The physics on that seem interesting. A little like stopping a speeding
> >> >> >bullet on a dime--it challenges my imagination. Probably not quite as
> >> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
> >> >> >either.
> >> >> >
> >> >> >Bill
> >> >> No way a caliper could stop the blade in even 4X the time the
> >> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >> >> the blade would be quite problematic - with dust decreasing the
> >> >> stopping efficiency by a very large margin.
> >> >
> >> >I suspect that a small pyrotechnic pressurizing one of the calipers off
> >> >my '76 Lincoln might surprise you.
> >> >
> >> But would also be totally impractical on a 10" saw.
> >
> >Why would it be "impractical on a 10" saw? The brake rotors on that car
> >are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
> >15" wheel.
> >
> You want to put that monstrosity on a tilting arbour saw, mounted
> under the saw table and in the path of the saw-dust and have it work
> reliably???
> Not going to happen - guaranteed.
It works reliably on a tilting Lincoln wheel in the path of rain, road
dust, and whatever else mother nature can throw at it, so why does a
nice, dry saw cabinet present such problems?
Do yourself a favor, pull a wheel off your car and _look_ at the
mechanism.
In article <[email protected]>, [email protected]
says...
>
> As I stated posters seem to lean towards the technology they are comfortable
> with.
>
> The mechanics would be a nightmare to me, also. To others the electronics
> would be a nightmare.
>
> Contactor and resistor?...way too complicated.
So tell us how to wire an induction motor to make the "contactor and
resistor" work.
>
>
> <[email protected]> wrote in message
> news:[email protected]...
> You want to put that monstrosity on a tilting arbour saw, mounted
> under the saw table and in the path of the saw-dust and have it work
> reliably???
> Not going to happen - guaranteed.
In article <[email protected]>, [email protected] says...
>
> Nobody wants to stop a saw blade in one rev. Convenience stop only.
>
> This was barked at when the SawStop came into comparison.
>
>
> "Scott Lurndal" <[email protected]> wrote in message
> news:[email protected]...
> A car wheel spinning at 5000RPM's isn't stopped within a single rotation
> by a caliper disc brake. Why would you expect a saw blade to be?
Because the blade masses a tiny fraction of what the car does.
> A car brake is designed to avoid locking up, yet that's exactly the
> behavior you would want with a sawblade, and you'd want it to lock in
> much less than a single revolution.
If a car brake doesn't ever lock then the car doesn't stop. In any
case, absent ABS it's possible to lock the brakes on any car on which
the brakes are in good condition. Don't believe me, put both feet on
the pedal and shove hard. If you have ABS then pull the fuse on it
first.
Josepi wrote:
> Look at what you posted. I quote
> -------------------------------------------
> "Josepi wrote:
>
>>
>> A car brake is designed to avoid locking up, yet that's exactly the
>> behavior you would want with a sawblade, and you'd want it to lock in
>> much less than a single revolution."
> ---------------------------------------------
>
> I did not post those words and my posting ID is always with my text
> not at opposite ends of the posting. It should have been clear with
> MOE reader. Agent and some of them make a fricking mess out of
> indentation.
>
> No big deal. Text mediums get messy after a while.
>
Nope - it might have been my problem, as you suggested. In attempting to
trim, I might have left an attribution in that I should not have. Any
hanging attributions though, should have been from previous replies, and not
associated with the most current reply. Oh well - did not mean to associate
something with you that you hadn't said.
--
-Mike-
[email protected]
Should have read. (I didn't write the attributed text)
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
ABS is designed to prevent lock up - car brakes are not.
--
"Josepi" <[email protected]> wrote in message
news:[email protected]...
Nobody wants to stop a saw blade in one rev. Convenience stop only.
This was barked at when the SawStop came into comparison.
"Scott Lurndal" <[email protected]> wrote in message
news:[email protected]...
A car wheel spinning at 5000RPM's isn't stopped within a single rotation
by a caliper disc brake. Why would you expect a saw blade to be?
A car brake is designed to avoid locking up, yet that's exactly the
behavior you would want with a sawblade, and you'd want it to lock in
much less than a single revolution.
On 10/15/2010 12:36 PM, Josepi wrote:
> Look at what you posted. I quote
> -------------------------------------------
> "Josepi wrote:
>
>>
>> A car brake is designed to avoid locking up, yet that's exactly the
>> behavior you would want with a sawblade, and you'd want it to lock in
>> much less than a single revolution."
> ---------------------------------------------
>
> I did not post those words and my posting ID is always with my text not at
> opposite ends of the posting. It should have been clear with MOE reader.
> Agent and some of them make a fricking mess out of indentation.
Only a top-posting moron like you would claim that Outlook Express is a
superior news reader. YOU and your stupid news reader are always taking a
perfectly good forward-reading conversation and turning it completely
backwards, and when YOUR actions cause somebody else to misinterpret the flow
and content of the conversation (what a surprise) YOU blame it on THEIR newsreader.
> No big deal. Text mediums get messy after a while.
Yeah, because of idiots like you.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/15/10 3:14 PM, Steve Turner wrote:
> On 10/15/2010 12:36 PM, Josepi wrote:
>
>> No big deal. Text mediums get messy after a while.
>
> Yeah, because of idiots like you.
>
He probably laments leaving webtv. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Wed, 13 Oct 2010 09:12:15 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>, markem618
>@hotmail.com says...
>>
>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >I suspect that a small pyrotechnic pressurizing one of the calipers off
>> >my '76 Lincoln might surprise you.
>>
>> Yes but the heat will do what to the saw blade?
>
>About the same thing it does to a brake rotor I suspect, polish the
>sides a little bit.
Uneven heating of a metal disc also would cause it to warp. But then
again the "cartridge" in a Sawstop is toast when activated.
The two times I trimmed my finger nails with a tablesaw was it was a
Delta TS220 I had at the time, I was in a hurry impatient a bit tired,
which equalled being stupid.
The Unisaw which I have now seems safer, and that is more than a
reason to be careful.
Mark
"J. Clarke" <[email protected]> writes:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> >> <[email protected]> wrote:
>> >>
>> >> >In article <[email protected]>,
>> >> >[email protected] says...
>> >> >>
>> >> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>> >> >>
>> >> >> >J. Clarke wrote:
>> >> >> >> In article<[email protected]>, [email protected] says...
>> >> >> >>>
>> >> >> >>> I would think that an emergency stop mechanism would be a whole different
>> >> >> >>> magnitude than a scheduled, everyday, stop.
>> >> >> >>>
>> >> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
>> >> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> >> >> >>> would be OK too. These two situations would require different tactics.
>> >> >> >>>
>> >> >> >>> A dynamic electronic brake could vary the intensity for the two different
>> >> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> >> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> >> >> >>> replaced frequently.
>> >> >> >>
>> >> >> >> So how much power do you have to put into that electronic brake to stop
>> >> >> >> the blade as fast as Sawstop's physical block?
>> >> >> >>
>> >> >> >> And why would a caliper not last long? A set of brake pads on a car
>> >> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> >> >> >> a lot more of a workout that they would stopping a little bitty saw
>> >> >> >> blade that masses less than 1/1000 as much.
>> >> >> >
>> >> >> >The physics on that seem interesting. A little like stopping a speeding
>> >> >> >bullet on a dime--it challenges my imagination. Probably not quite as
>> >> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
>> >> >> >either.
>> >> >> >
>> >> >> >Bill
>> >> >> No way a caliper could stop the blade in even 4X the time the
>> >> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> >> >> the blade would be quite problematic - with dust decreasing the
>> >> >> stopping efficiency by a very large margin.
>> >> >
>> >> >I suspect that a small pyrotechnic pressurizing one of the calipers off
>> >> >my '76 Lincoln might surprise you.
>> >> >
>> >> But would also be totally impractical on a 10" saw.
>> >
>> >Why would it be "impractical on a 10" saw? The brake rotors on that car
>> >are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
>> >15" wheel.
>> >
>> You want to put that monstrosity on a tilting arbour saw, mounted
>> under the saw table and in the path of the saw-dust and have it work
>> reliably???
>> Not going to happen - guaranteed.
>
>It works reliably on a tilting Lincoln wheel in the path of rain, road
>dust, and whatever else mother nature can throw at it, so why does a
>nice, dry saw cabinet present such problems?
>
>Do yourself a favor, pull a wheel off your car and _look_ at the
>mechanism.
>
A car wheel spinning at 5000RPM's isn't stopped within a single rotation
by a caliper disc brake. Why would you expect a saw blade to be?
A car brake is designed to avoid locking up, yet that's exactly the
behavior you would want with a sawblade, and you'd want it to lock in
much less than a single revolution.
Nobody wants to stop a saw blade in one rev. Convenience stop only.
This was barked at when the SawStop came into comparison.
"Scott Lurndal" <[email protected]> wrote in message
news:[email protected]...
A car wheel spinning at 5000RPM's isn't stopped within a single rotation
by a caliper disc brake. Why would you expect a saw blade to be?
A car brake is designed to avoid locking up, yet that's exactly the
behavior you would want with a sawblade, and you'd want it to lock in
much less than a single revolution.
In article <[email protected]>,
> >
>
> A car wheel spinning at 5000RPM's isn't stopped within a single rotation
> by a caliper disc brake. Why would you expect a saw blade to be?
>
On an average wheel, that would be 330+ mph (Or therabouts ± 50 mph)
I don't think you'd want to stop that tire in one rotation. <G>
Look at what you posted. I quote
-------------------------------------------
"Josepi wrote:
>
> A car brake is designed to avoid locking up, yet that's exactly the
> behavior you would want with a sawblade, and you'd want it to lock in
> much less than a single revolution."
---------------------------------------------
I did not post those words and my posting ID is always with my text not at
opposite ends of the posting. It should have been clear with MOE reader.
Agent and some of them make a fricking mess out of indentation.
No big deal. Text mediums get messy after a while.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
Josepi wrote:
> Should have read. (I didn't write the attributed text)
>
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> ABS is designed to prevent lock up - car brakes are not.
Not sure what you are trying to point out. I did a simple reply all. The
problems come in when people like yourself insist on replying in a manner
that defies normal attributions. Really do not understand what your
statement "Should have read" means.
--
-Mike-
[email protected]
On 10/10/10 9:22 PM, Larry Jaques wrote:
> On Sun, 10 Oct 2010 17:30:01 -0500, -MIKE-<[email protected]>
> wrote:
>
>> On 10/10/10 4:51 PM, Larry Jaques wrote:
>>> On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE-<[email protected]>
>>> wrote:
>>>
>>>> On 10/10/10 11:35 AM, willshak wrote:
>>>>> WW wrote the following:
>>>>>> "HeyBub"<[email protected]> wrote in message
>>>>>> news:[email protected]...
>>>>>>> Found this article...
>>>>>>>
>>>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>>>>> in the home workshop. Stationary grinders, table and radial arm
>>>>>>> circular saws frequently turn abrasive or cutting disks that are
>>>>>>> directly mounted on the motor's spindle. These disks have large
>>>>>>> inertial moments that allow them to free wheel for a long time after
>>>>>>> the power is turned off. A lengthy coast to complete stop often
>>>>>>> amounts to a major inconvenience."
>>>>>>>
>>>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>>>>
>>>>>>>
>>>>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>>>>> brake. WW
>>>>>
>>>>> If I need to stop a spinning table saw blade in a hurry to change or
>>>>> reset something, I find that a scrap piece of lumber makes a great blade
>>>>> brake. Turn the saw off and slide the scrap up to the still spinning
>>>>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>>>>
>>>>
>>>> Someone could make some money by developing an aftermarket saw brake,
>>>> under the table.... pads or rollers or whatever, that would squeeze the
>>>> blade.
>>>
>>> Lawsuits from the arse with the SawStop patents notwithstanding, I
>>> think he went with the positive stop style because it's the only one
>>> which would keep from taking a finger off. The rest spin just enough
>>> to do serious damage.
>>>
>>
>> A saw blade brake wouldn't infringe on SawStop's patent at all.
>
> WTF does that have to do with lawsuits? People sue to keep their
> product on top whether they have a case or not. REAL WORLD, Mike.
>
In the "REAL WORLD" (relax, man), patent infringement law suits get
thrown out in the first hearing, too, Larry. What, you're a patent
attorney, too?
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/10/10 10:34 PM, Josepi wrote:
> For fast stops a powered brake on may be preferred to normally brake on with
> a spring setting the speed and strength to be held open all the time.
>
I would prefer powered off/normal on, because the operator would get
used to the blade always braking and in the case of a solenoid failure,
the blade would not coast.
I would also think an assembly with wheels applying just a little
pressure to the sides of the blade would make a decent passive system.
It would be just enough pressure to slow down the blade in a second or
two and not enough pressure for the motor to even register the resistance.
Think about how little pressure it takes with a scrap piece of wood to
stop a coasting blade.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Wed, 13 Oct 2010 23:15:27 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> >> <[email protected]> wrote:
>> >>
>> >> >In article <[email protected]>,
>> >> >[email protected] says...
>> >> >>
>> >> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>> >> >>
>> >> >> >J. Clarke wrote:
>> >> >> >> In article<[email protected]>, [email protected] says...
>> >> >> >>>
>> >> >> >>> I would think that an emergency stop mechanism would be a whole different
>> >> >> >>> magnitude than a scheduled, everyday, stop.
>> >> >> >>>
>> >> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
>> >> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> >> >> >>> would be OK too. These two situations would require different tactics.
>> >> >> >>>
>> >> >> >>> A dynamic electronic brake could vary the intensity for the two different
>> >> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> >> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> >> >> >>> replaced frequently.
>> >> >> >>
>> >> >> >> So how much power do you have to put into that electronic brake to stop
>> >> >> >> the blade as fast as Sawstop's physical block?
>> >> >> >>
>> >> >> >> And why would a caliper not last long? A set of brake pads on a car
>> >> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> >> >> >> a lot more of a workout that they would stopping a little bitty saw
>> >> >> >> blade that masses less than 1/1000 as much.
>> >> >> >
>> >> >> >The physics on that seem interesting. A little like stopping a speeding
>> >> >> >bullet on a dime--it challenges my imagination. Probably not quite as
>> >> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
>> >> >> >either.
>> >> >> >
>> >> >> >Bill
>> >> >> No way a caliper could stop the blade in even 4X the time the
>> >> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> >> >> the blade would be quite problematic - with dust decreasing the
>> >> >> stopping efficiency by a very large margin.
>> >> >
>> >> >I suspect that a small pyrotechnic pressurizing one of the calipers off
>> >> >my '76 Lincoln might surprise you.
>> >> >
>> >> But would also be totally impractical on a 10" saw.
>> >
>> >Why would it be "impractical on a 10" saw? The brake rotors on that car
>> >are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
>> >15" wheel.
>> >
>> You want to put that monstrosity on a tilting arbour saw, mounted
>> under the saw table and in the path of the saw-dust and have it work
>> reliably???
>> Not going to happen - guaranteed.
>
>It works reliably on a tilting Lincoln wheel in the path of rain, road
>dust, and whatever else mother nature can throw at it, so why does a
>nice, dry saw cabinet present such problems?
>
>Do yourself a favor, pull a wheel off your car and _look_ at the
>mechanism.
>
I've been doing it for over 45 years
I've also rebuilt a few tilting arbour saws - both belt drive, gear
drive, and direct drive..
On Wed, 13 Oct 2010 22:52:34 -0400, "Josepi" <[email protected]>
wrote:
>As I stated posters seem to lean towards the technology they are comfortable
>with.
>
>The mechanics would be a nightmare to me, also. To others the electronics
>would be a nightmare.
>
>Contactor and resistor?...way too complicated.
>
>
><[email protected]> wrote in message
>news:[email protected]...
> You want to put that monstrosity on a tilting arbour saw, mounted
>under the saw table and in the path of the saw-dust and have it work
>reliably???
> Not going to happen - guaranteed.
>
It's BECAUSE I was a mechanic for several decades that I would NOT use
a brake caliper for the application.
On Fri, 15 Oct 2010 13:23:47 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Thu, 14 Oct 2010 22:18:51 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> [email protected] wrote:
>>>
>>>>
>>>> Never see the black staining in oak from non-galvanized nails? That
>>>> is due to corrosion. Doesn't take much corrosion to make a caliper
>>>> just fussy enough that it might not do the required job (for which
>>>> it was not designed).
>>>>
>>>
>>> I thought you worked on cars Clare. Have you ever seen a caliper
>>> that was *not corroded*? You're exagerating things in attempt to
>>> bolster your point but again, it's just not true.
>> The outer frame of the caliper can be corroded all to heck - no
>> problem. If the slider mechanism is corroded (which it often is)
>> braking is less linear, and less predictable. They can (and do) drag.
>> They can also apply late.
>>
>> If the piston gets corroded, all the same, but a lot worse.
>
>You are thinking of car brakes and not of calipers in general. That said -
>every piece of metal on a car caliper assembly corrodes, yet they continue
>to work until the corrosion on the slide becomes excessive. Not something a
>table saw would likely see. I agree that with a corroded slider, braking is
>less linear, but again, a table saw would not even require a slider, so the
>direct comparison to a car caliper need not be made. Calipers exist outside
>of the world of automobiles and calipers could make a perfectly acceptable
>solution (one of many options) for a table saw. No one has suggested a car
>caliper for a table saw, but instead has compared a comparatively hostile
>environment where one type of caliper has proven itself.
By definition a "caliper" squeeses - so by definition it requires
some sort of equalization between the forces from side to side of the
"rotor" which means either a slider or a dual piston type caliper.
And the "lincoln" caloper was the first suggestion of a caliper for
saw stopping in this thread.
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 13:23:47 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
> >[email protected] wrote:
> >> On Thu, 14 Oct 2010 22:18:51 -0400, "Mike Marlow"
> >> <[email protected]> wrote:
> >>
> >>> [email protected] wrote:
> >>>
> >>>>
> >>>> Never see the black staining in oak from non-galvanized nails? That
> >>>> is due to corrosion. Doesn't take much corrosion to make a caliper
> >>>> just fussy enough that it might not do the required job (for which
> >>>> it was not designed).
> >>>>
> >>>
> >>> I thought you worked on cars Clare. Have you ever seen a caliper
> >>> that was *not corroded*? You're exagerating things in attempt to
> >>> bolster your point but again, it's just not true.
> >> The outer frame of the caliper can be corroded all to heck - no
> >> problem. If the slider mechanism is corroded (which it often is)
> >> braking is less linear, and less predictable. They can (and do) drag.
> >> They can also apply late.
> >>
> >> If the piston gets corroded, all the same, but a lot worse.
> >
> >You are thinking of car brakes and not of calipers in general. That said -
> >every piece of metal on a car caliper assembly corrodes, yet they continue
> >to work until the corrosion on the slide becomes excessive. Not something a
> >table saw would likely see. I agree that with a corroded slider, braking is
> >less linear, but again, a table saw would not even require a slider, so the
> >direct comparison to a car caliper need not be made. Calipers exist outside
> >of the world of automobiles and calipers could make a perfectly acceptable
> >solution (one of many options) for a table saw. No one has suggested a car
> >caliper for a table saw, but instead has compared a comparatively hostile
> >environment where one type of caliper has proven itself.
> By definition a "caliper" squeeses - so by definition it requires
> some sort of equalization between the forces from side to side of the
> "rotor" which means either a slider or a dual piston type caliper.
>
> And the "lincoln" caloper was the first suggestion of a caliper for
> saw stopping in this thread.
Asperger's much?
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 17:52:33 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Fri, 15 Oct 2010 09:32:43 -0400, "J. Clarke"
> >> <[email protected]> wrote:
> >>
> >> >In article <[email protected]>,
> >> >[email protected] says...
> >> >>
> >> >> On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
> >> >> <[email protected]> wrote:
> >> >>
> >> >> >On 10/14/2010 2:52 PM, [email protected] wrote:
> >> >> >> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
> >> >> >> <[email protected]> wrote:
> >> >> >>
> >> >> >>> Larry Jaques wrote:
> >> >> >>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
> >> >> >>>> <[email protected]> wrote:
> >> >> >>>
> >> >> >>>>>
> >> >> >>>>> As a guy who has done all of his own vehicle maintenance for 40
> >> >> >>>>> years now, I have to ask what you observed in your experiences, that
> >> >> >>>>> causes you to make this statement? I don't know if the brake
> >> >> >>>>> caliper idea is the most elegant solution, but I sure can't see
> >> >> >>>>> anything in what you are saying that would suggest it is not a
> >> >> >>>>> workable solution.
> >> >> >>>>
> >> >> >>>> Suitable placement of an air nozzle tube to clear the caliper frame
> >> >> >>>> every hour or so would go far into making this device work for more
> >> >> >>>> than an hour. You'd have to keep the sawdust from piercing the seals
> >> >> >>>> and/or building up on the frame
> >> >> >>>
> >> >> >>> Not at all Larry, if you consider what a normal brake caliper in an
> >> >> >>> automobile is subject to. In comparison, the environment inside a table saw
> >> >> >>> would be a walk in the part of a caliper.
> >> >> >>
> >> >> >>
> >> >> >> You get a splinter of oak thrown at a rubber caliper boot at 18000
> >> >> >> feet per minute (almost 205MPH) a few times and expect the boot to
> >> >> >> survive?. For the brake to see the same rotational RPM on a car with
> >> >> >> 24" diameter tires (pretty standard today) you would need to drive
> >> >> >> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
> >> >> >>
> >> >> >> A 10" saw runs closer to 5200 RPM - so 370 MPH.
> >> >> >
> >> >> >Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
> >> >> >would be even more impossible to stop.
> >> >> >
> >> >>
> >> >> No, I said nothing of the sort. I didn't even say anything about it
> >> >> being hard to stop. I was comaring the speed at which particals might
> >> >> possibly hit the boot on the lincoln caliper some dufus was talking
> >> >> about mounting to the table saw to stop the blade, The speed at which
> >> >> a sliver could be flung at that boot from a typical table saw blade
> >> >> would require the above mentioned speeds with the caliper on a car -
> >> >> assuming the bit was picked up from the road or thrown from the
> >> >> circumference of the tire.
> >> >> >> Also, the caliper is actually pretty well protected mounted as it is
> >> >> >> virtually inside the wheel - with the caliper boot protected between
> >> >> >> the pad and tha caliper frame, and usually behind a splash shield as
> >> >> >> well.
> >> >> >>
> >> >> >> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> >> >> >> onto every surface of the caliper.
> >> >> >
> >> >> >Geez Chicken Little, how many mountains are you going to make out of molehills
> >> >> >on this topic? Just about every point you've tried to make has had the air of
> >> >> >doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
> >> >>
> >> >> Nobody said it was difficult. Just saying the brake from the old
> >> >> lincoln is NOT going to be anywhere close to an effective solution.
> >> >> So many guys on the Wreck just make things WAY too complicated.
> >> >>
> >> >> You want a convenience brake on an AC table saw? DC injection braking
> >> >> is as simple as it gets and can be done by a reasonably adept
> >> >> scrounger for less than $25 in less than an hour, with NO
> >> >> modifications to the physical part of the saw. Just grabbing a few
> >> >> parts out of my scrap bin I could have it working on a saw in less
> >> >> than half an hour with no cash outlay at all. Not fully automated -
> >> >> but hit the stop button or turn off the power and press a pushbutton
> >> >> untill the blade stops (about 2 seconds) using nothing more than an
> >> >> old PC power supply and a pushbutton switch. To make it a littlemore
> >> >> foolproof the power switch would need to be replaces with a SPDT or
> >> >> DPDT switch or augmented by a relay to prevent injecting the DC while
> >> >> the AC was still connected.
> >> >
> >> >But if I have to push a button to stop the blade I may as well just
> >> >shove a pushstick into the side of it.
> >> >
> >> Which is why using the DPDT switch makes it foolproof. and simple
> >> circuitry can handle the injection current timing.
> >
> >So where can I buy a DPDT switch with a big red "off" button that I can
> >hit with my knee?
> >
> If you have an OFF button it is contactor controlled - you simply
> change the contactor.
So where is the "contactor" on my Ridgid table saw and my Craftman band
saw, and why is there no "OFF" button on my contactor-controlled dust
collector?
On Fri, 15 Oct 2010 17:52:33 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Fri, 15 Oct 2010 09:32:43 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
>> >> <[email protected]> wrote:
>> >>
>> >> >On 10/14/2010 2:52 PM, [email protected] wrote:
>> >> >> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
>> >> >> <[email protected]> wrote:
>> >> >>
>> >> >>> Larry Jaques wrote:
>> >> >>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>> >> >>>> <[email protected]> wrote:
>> >> >>>
>> >> >>>>>
>> >> >>>>> As a guy who has done all of his own vehicle maintenance for 40
>> >> >>>>> years now, I have to ask what you observed in your experiences, that
>> >> >>>>> causes you to make this statement? I don't know if the brake
>> >> >>>>> caliper idea is the most elegant solution, but I sure can't see
>> >> >>>>> anything in what you are saying that would suggest it is not a
>> >> >>>>> workable solution.
>> >> >>>>
>> >> >>>> Suitable placement of an air nozzle tube to clear the caliper frame
>> >> >>>> every hour or so would go far into making this device work for more
>> >> >>>> than an hour. You'd have to keep the sawdust from piercing the seals
>> >> >>>> and/or building up on the frame
>> >> >>>
>> >> >>> Not at all Larry, if you consider what a normal brake caliper in an
>> >> >>> automobile is subject to. In comparison, the environment inside a table saw
>> >> >>> would be a walk in the part of a caliper.
>> >> >>
>> >> >>
>> >> >> You get a splinter of oak thrown at a rubber caliper boot at 18000
>> >> >> feet per minute (almost 205MPH) a few times and expect the boot to
>> >> >> survive?. For the brake to see the same rotational RPM on a car with
>> >> >> 24" diameter tires (pretty standard today) you would need to drive
>> >> >> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
>> >> >>
>> >> >> A 10" saw runs closer to 5200 RPM - so 370 MPH.
>> >> >
>> >> >Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
>> >> >would be even more impossible to stop.
>> >> >
>> >>
>> >> No, I said nothing of the sort. I didn't even say anything about it
>> >> being hard to stop. I was comaring the speed at which particals might
>> >> possibly hit the boot on the lincoln caliper some dufus was talking
>> >> about mounting to the table saw to stop the blade, The speed at which
>> >> a sliver could be flung at that boot from a typical table saw blade
>> >> would require the above mentioned speeds with the caliper on a car -
>> >> assuming the bit was picked up from the road or thrown from the
>> >> circumference of the tire.
>> >> >> Also, the caliper is actually pretty well protected mounted as it is
>> >> >> virtually inside the wheel - with the caliper boot protected between
>> >> >> the pad and tha caliper frame, and usually behind a splash shield as
>> >> >> well.
>> >> >>
>> >> >> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>> >> >> onto every surface of the caliper.
>> >> >
>> >> >Geez Chicken Little, how many mountains are you going to make out of molehills
>> >> >on this topic? Just about every point you've tried to make has had the air of
>> >> >doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
>> >>
>> >> Nobody said it was difficult. Just saying the brake from the old
>> >> lincoln is NOT going to be anywhere close to an effective solution.
>> >> So many guys on the Wreck just make things WAY too complicated.
>> >>
>> >> You want a convenience brake on an AC table saw? DC injection braking
>> >> is as simple as it gets and can be done by a reasonably adept
>> >> scrounger for less than $25 in less than an hour, with NO
>> >> modifications to the physical part of the saw. Just grabbing a few
>> >> parts out of my scrap bin I could have it working on a saw in less
>> >> than half an hour with no cash outlay at all. Not fully automated -
>> >> but hit the stop button or turn off the power and press a pushbutton
>> >> untill the blade stops (about 2 seconds) using nothing more than an
>> >> old PC power supply and a pushbutton switch. To make it a littlemore
>> >> foolproof the power switch would need to be replaces with a SPDT or
>> >> DPDT switch or augmented by a relay to prevent injecting the DC while
>> >> the AC was still connected.
>> >
>> >But if I have to push a button to stop the blade I may as well just
>> >shove a pushstick into the side of it.
>> >
>> Which is why using the DPDT switch makes it foolproof. and simple
>> circuitry can handle the injection current timing.
>
>So where can I buy a DPDT switch with a big red "off" button that I can
>hit with my knee?
>
If you have an OFF button it is contactor controlled - you simply
change the contactor.
[email protected] wrote:
> On Wed, 13 Oct 2010 22:52:34 -0400, "Josepi" <[email protected]>
> wrote:
>
>> As I stated posters seem to lean towards the technology they are
>> comfortable with.
>>
>> The mechanics would be a nightmare to me, also. To others the
>> electronics would be a nightmare.
>>
>> Contactor and resistor?...way too complicated.
>>
>>
>> <[email protected]> wrote in message
>> news:[email protected]...
>> You want to put that monstrosity on a tilting arbour saw, mounted
>> under the saw table and in the path of the saw-dust and have it work
>> reliably???
>> Not going to happen - guaranteed.
>>
> It's BECAUSE I was a mechanic for several decades that I would NOT use
> a brake caliper for the application.
As a guy who has done all of his own vehicle maintenance for 40 years now, I
have to ask what you observed in your experiences, that causes you to make
this statement? I don't know if the brake caliper idea is the most elegant
solution, but I sure can't see anything in what you are saying that would
suggest it is not a workable solution.
--
-Mike-
[email protected]
On Thu, 14 Oct 2010 22:08:03 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 7:01 PM, Robatoy wrote:
>> On Oct 14, 7:52 pm, -MIKE-<[email protected]> wrote:
>>> On 10/14/10 6:40 PM, [email protected] wrote:
>>>
>>>
>>>
>>>
>>>
>>>> On Thu, 14 Oct 2010 17:26:59 -0500, -MIKE-<[email protected]>
>>>> wrote:
>>>
>>>>> On 10/14/10 5:06 PM, Robatoy wrote:
>>>>>> In article<[email protected]>,
>>>>>> [email protected] wrote:
>>>
>>>>>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>>>>>>> onto every surface of the caliper.
>>>
>>>>>> More corrosive than road salt?
>>>
>>>>> More corrosive than brake fluid? Because calipers neeeeeever leak.
>>>> Brake fluid itself is not corrosive. When it absorbs moisture it is -
>>>> and brake fluid is highly hygroscopic.
>>>
>>> I guess I was wrong then.
>>> sheesh
>>>
>> what does it feel like, Mike?
>>
>I was being fesesiou.... phesesu... feseeshus..... sarcastic.
>
>I thought I was wrong once, but I was mistaken.
so THAT time you WERE wrong - admit it. You actually thought you were
wrong when you weren't.
In article <[email protected]>,
[email protected] says...
>
> On Wed, 13 Oct 2010 23:15:27 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
> >> <[email protected]> wrote:
> >>
> >> >In article <[email protected]>,
> >> >[email protected] says...
> >> >>
> >> >> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> >> >> <[email protected]> wrote:
> >> >>
> >> >> >In article <[email protected]>,
> >> >> >[email protected] says...
> >> >> >>
> >> >> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
> >> >> >>
> >> >> >> >J. Clarke wrote:
> >> >> >> >> In article<[email protected]>, [email protected] says...
> >> >> >> >>>
> >> >> >> >>> I would think that an emergency stop mechanism would be a whole different
> >> >> >> >>> magnitude than a scheduled, everyday, stop.
> >> >> >> >>>
> >> >> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
> >> >> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >> >> >> >>> would be OK too. These two situations would require different tactics.
> >> >> >> >>>
> >> >> >> >>> A dynamic electronic brake could vary the intensity for the two different
> >> >> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >> >> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >> >> >> >>> replaced frequently.
> >> >> >> >>
> >> >> >> >> So how much power do you have to put into that electronic brake to stop
> >> >> >> >> the blade as fast as Sawstop's physical block?
> >> >> >> >>
> >> >> >> >> And why would a caliper not last long? A set of brake pads on a car
> >> >> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >> >> >> >> a lot more of a workout that they would stopping a little bitty saw
> >> >> >> >> blade that masses less than 1/1000 as much.
> >> >> >> >
> >> >> >> >The physics on that seem interesting. A little like stopping a speeding
> >> >> >> >bullet on a dime--it challenges my imagination. Probably not quite as
> >> >> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
> >> >> >> >either.
> >> >> >> >
> >> >> >> >Bill
> >> >> >> No way a caliper could stop the blade in even 4X the time the
> >> >> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >> >> >> the blade would be quite problematic - with dust decreasing the
> >> >> >> stopping efficiency by a very large margin.
> >> >> >
> >> >> >I suspect that a small pyrotechnic pressurizing one of the calipers off
> >> >> >my '76 Lincoln might surprise you.
> >> >> >
> >> >> But would also be totally impractical on a 10" saw.
> >> >
> >> >Why would it be "impractical on a 10" saw? The brake rotors on that car
> >> >are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
> >> >15" wheel.
> >> >
> >> You want to put that monstrosity on a tilting arbour saw, mounted
> >> under the saw table and in the path of the saw-dust and have it work
> >> reliably???
> >> Not going to happen - guaranteed.
> >
> >It works reliably on a tilting Lincoln wheel in the path of rain, road
> >dust, and whatever else mother nature can throw at it, so why does a
> >nice, dry saw cabinet present such problems?
> >
> >Do yourself a favor, pull a wheel off your car and _look_ at the
> >mechanism.
> >
> I've been doing it for over 45 years
> I've also rebuilt a few tilting arbour saws - both belt drive, gear
> drive, and direct drive..
And yet you see a problem.
On Wed, 13 Oct 2010 22:25:01 -0500, "HeyBub" <[email protected]>
wrote:
>[email protected] wrote:
>>>
>>> Why would it be "impractical on a 10" saw? The brake rotors on that
>>> car are IIRC 11.5 inch diameter and the whole brake assembly fits
>>> inside a 15" wheel.
>>>
>> You want to put that monstrosity on a tilting arbour saw, mounted
>> under the saw table and in the path of the saw-dust and have it work
>> reliably???
>> Not going to happen - guaranteed.
>
>You want to put that goober under a car where it has to contend with dirt,
>water, oil, ice, salt, road-kill entrails, and have it work reliably???
>
>Common sense says it won't work and can't be made to work. Don't believe
>your lyin' eyes.
>
It's the clearance issues around a tilting arbour more than the dirt
and sawdust. A purpose built caliper could be used on the opposite end
of the motor on a direct drive saw - but a drum would be just as
effective and smaller for the same stopping power. You don't need the
fade resistance of a disk brake for the application, nor the thermal
mass of a Lincoln car caliper.
Josepi wrote:
> I would think that an emergency stop mechanism would be a whole different
> magnitude than a scheduled, everyday, stop.
indeed...
> For a finger saver an emergency stop mechanism would have to stop the blade
> in a few teeth passings. ...
SawStop is a few (10's of iirc) msec.
By several "tooth passings" a finger is already pretty well history...
--
On 10/11/10 12:13 AM, J. Clarke wrote:
> In article<[email protected]>,
> [email protected] says...
>>
>> On 10/10/10 9:22 PM, Larry Jaques wrote:
>>> On Sun, 10 Oct 2010 17:30:01 -0500, -MIKE-<[email protected]>
>>> wrote:
>>>
>>>> On 10/10/10 4:51 PM, Larry Jaques wrote:
>>>>> On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE-<[email protected]>
>>>>> wrote:
>>>>>
>>>>>> On 10/10/10 11:35 AM, willshak wrote:
>>>>>>> WW wrote the following:
>>>>>>>> "HeyBub"<[email protected]> wrote in message
>>>>>>>> news:[email protected]...
>>>>>>>>> Found this article...
>>>>>>>>>
>>>>>>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>>>>>>> in the home workshop. Stationary grinders, table and radial arm
>>>>>>>>> circular saws frequently turn abrasive or cutting disks that are
>>>>>>>>> directly mounted on the motor's spindle. These disks have large
>>>>>>>>> inertial moments that allow them to free wheel for a long time after
>>>>>>>>> the power is turned off. A lengthy coast to complete stop often
>>>>>>>>> amounts to a major inconvenience."
>>>>>>>>>
>>>>>>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>>>>>>> brake. WW
>>>>>>>
>>>>>>> If I need to stop a spinning table saw blade in a hurry to change or
>>>>>>> reset something, I find that a scrap piece of lumber makes a great blade
>>>>>>> brake. Turn the saw off and slide the scrap up to the still spinning
>>>>>>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>>>>>>
>>>>>>
>>>>>> Someone could make some money by developing an aftermarket saw brake,
>>>>>> under the table.... pads or rollers or whatever, that would squeeze the
>>>>>> blade.
>>>>>
>>>>> Lawsuits from the arse with the SawStop patents notwithstanding, I
>>>>> think he went with the positive stop style because it's the only one
>>>>> which would keep from taking a finger off. The rest spin just enough
>>>>> to do serious damage.
>>>>>
>>>>
>>>> A saw blade brake wouldn't infringe on SawStop's patent at all.
>>>
>>> WTF does that have to do with lawsuits? People sue to keep their
>>> product on top whether they have a case or not. REAL WORLD, Mike.
>>>
>>
>> In the "REAL WORLD" (relax, man), patent infringement law suits get
>> thrown out in the first hearing, too, Larry. What, you're a patent
>> attorney, too?
>
> In any case, since EU law requires brakes already (indirectly, with an
> allowed spindown time IIRC), Sawstop would have an uphill battle
> claiming that they infringe its patents.
>
Especially since it's apples and oranges.
SawStop is a safety brake that only stops when contact with flesh is
made, and it's instantaneous.
I'm talking about a gradual brake that occurs as part of normal operation.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/11/10 7:11 AM, HeyBub wrote:
> -MIKE- wrote:
>
>>
>> I would prefer powered off/normal on, because the operator would get
>> used to the blade always braking and in the case of a solenoid
>> failure, the blade would not coast.
>>
>> I would also think an assembly with wheels applying just a little
>> pressure to the sides of the blade would make a decent passive system.
>> It would be just enough pressure to slow down the blade in a second or
>> two and not enough pressure for the motor to even register the
>> resistance.
>> Think about how little pressure it takes with a scrap piece of wood to
>> stop a coasting blade.
>
> Isn't there an old Indian trick about a spinning piece of wood and starting
> a fire?
>
Point?
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/11/10 9:01 AM, Larry Jaques wrote:
> On Sun, 10 Oct 2010 21:41:24 -0500, -MIKE-<[email protected]>
> wrote:
>
>> On 10/10/10 9:22 PM, Larry Jaques wrote:
>
>>> WTF does that have to do with lawsuits? People sue to keep their
>>> product on top whether they have a case or not. REAL WORLD, Mike.
>>>
>>
>> In the "REAL WORLD" (relax, man), patent infringement law suits get
>> thrown out in the first hearing, too, Larry. What, you're a patent
>> attorney, too?
>
> No, I've just been horrified at how many frivolous lawsuits make it
> into court, including patent infringement suits. Check it out.
>
I understand and it is certainly frustrating.
But, if we let that deter us, not one would ever invent anything.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/11/10 12:08 PM, J. Clarke wrote:
> In article<[email protected]>, [email protected]
> says...
>>
>> Josepi wrote:
>>> I would think that an emergency stop mechanism would be a whole different
>>> magnitude than a scheduled, everyday, stop.
>>
>> indeed...
>>
>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>> in a few teeth passings. ...
>>
>> SawStop is a few (10's of iirc) msec.
>>
>> By several "tooth passings" a finger is already pretty well history...
>
> Sawstop stops the blade in 1/200 of a second, according to their Web
> site. At 3450 RPM that means the blade stops in .29 revolution, which
> with a 60 tooth blade means that 17 teeth have had a shot at your
> finger.
>
That may be true, but they still don't do any harm.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/11/10 3:05 PM, HeyBub wrote:
> -MIKE- wrote:
>> On 10/11/10 7:11 AM, HeyBub wrote:
>>> -MIKE- wrote:
>>>
>>>>
>>>> I would prefer powered off/normal on, because the operator would get
>>>> used to the blade always braking and in the case of a solenoid
>>>> failure, the blade would not coast.
>>>>
>>>> I would also think an assembly with wheels applying just a little
>>>> pressure to the sides of the blade would make a decent passive
>>>> system. It would be just enough pressure to slow down the blade in
>>>> a second or two and not enough pressure for the motor to even
>>>> register the resistance.
>>>> Think about how little pressure it takes with a scrap piece of wood
>>>> to stop a coasting blade.
>>>
>>> Isn't there an old Indian trick about a spinning piece of wood and
>>> starting a fire?
>>>
>>
>> Point?
>
> Everybody knows that, which is why I'm trying to explain. But everyone's
> alive except those who drowned in an adjacent bog.
>
Put down the pipe. :-p
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
J. Clarke wrote:
> In article<[email protected]>, [email protected] says...
>>
>> I would think that an emergency stop mechanism would be a whole different
>> magnitude than a scheduled, everyday, stop.
>>
>> For a finger saver an emergency stop mechanism would have to stop the blade
>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> would be OK too. These two situations would require different tactics.
>>
>> A dynamic electronic brake could vary the intensity for the two different
>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> replaced frequently.
>
> So how much power do you have to put into that electronic brake to stop
> the blade as fast as Sawstop's physical block?
>
> And why would a caliper not last long? A set of brake pads on a car
> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> a lot more of a workout that they would stopping a little bitty saw
> blade that masses less than 1/1000 as much.
The physics on that seem interesting. A little like stopping a speeding
bullet on a dime--it challenges my imagination. Probably not quite as
difficult as stopping a lightning bolt, but I wouldn't want to try that
either.
Bill
On Oct 15, 1:31=A0pm, "Josepi" <[email protected]> wrote:
> Sorry you asre twisting words and playing with semantics.
>
> Brake lock-up is not when the wheel stops turning. It is when the brakes
> will not let go and cease to act linearly.
>
> ABS was not created for brake lock-up. ABS would not help this problem.
>
You are completely and totally wrong and incorrect.
ABS, by definition, stands for Anti-lock Braking System. Now apply
this little bit of knowledge to your position, and you will see that
you are wrong, incorrect and mistaken.
Brake lock-up is lock-up caused by a brake, NOT a brake locking up.
ABS does not stand for Anti Brake Locking Up System.
With me yet?
Also, when you find yourself in a hole, stop digging.
In article <[email protected]>,
[email protected] says...
>
> On Wed, 13 Oct 2010 18:34:56 -0400, Bill <[email protected]> wrote:
>
> >J. Clarke wrote:
> >> In article<[email protected]>, [email protected] says...
> >>>
> >>> J. Clarke wrote:
> >>>
> >>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
> >>>>>>>> my '76 Lincoln might surprise you.
> >>>>>>>>
> >>>>>>> Bill>
> >>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
> >>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
> >>>
> >>>>>> J. Clarke>
> >>>>>> Why would something that can stop a 4000 pound car "snap" when called on
> >>>>>> to stop a 3 pound saw blade?
> >>>
> >>>>> Bill>
> >>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
> >>>>
> >>> >J. Clarke>
> >>>> To stop the saw in a fraction of a revolution, you need rapid
> >>>> application. A pyro will build pressure rapidly.
> >>>
> >>> That is what I what I might expect to increase the probability of failure.
> >>>
> >>> Given blade radius and density, and rpm, you could probably integrate to
> >>> compute the (foot-pounds of) energy that need to be stopped in a small
> >>> fraction of a second (I hope that the dust on the blade won't be an
> >>> issue). :) I've seen you post in another "forum" so I believe you are
> >>> up to the calculation. I do not have engineering background to back me
> >>> up, I'm just thinking it through with you and everyone else who is
> >>> reading. Evidently, you'll need to generate the equivalent of an equal
> >>> and opposite amount of energy. This means, I think, that you only get
> >>> the benefit of a "projection" (dot product) and not all of the force you
> >>> can apply to the side of the blade. My reasoning could definitely be
> >>> off, maybe a physicist or engineer could help out?
> >>
> >> Disk brakes work by friction. The energy comes off as heat. Apply F to
> >> the brake, k * F is the braking force where k is the coefficient of
> >> friction.
> >>
> >> Back of the envelope it looks like the Lincoln brake at Lincoln pressure
> >> can stop it in about 1/3 revolution. Don't know how much higher
> >> pressure that caliper can take--at 2x the pressure might be able to do
> >> it in 1/6 revolution, which puts it in Sawstop territory.
> >>
> >Interesting. Thank you. I'm not sure about your "imposter"..
> >
> >Bill
> This is all assuming a clean blade for the proper high co-efficient
> of friction.
> Dust od sap build-up on the blade can change that very quickly.
But we don't know which way it changes. Brake pad material isn't all
that high-friction you know.
In article <[email protected]>, [email protected] says...
>
> Disc brake were around for a lot longer than the ABS systems were ever
> implemented.
> Disc brakes were not sdesigned to "lock up" but rather be more linear than
> shoe brake systems, and fade less.
>
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> No they aren't. ABS systems are designed to prevent the wheel from locking
> up, but disk brakes aren't. In fact, quite the opposite, they are designed
> to lock up but rely upon the ABS to govern them so they don't.
They're not "designed to lock up", they're designed as a compromise
between maximum braking force, fade, pad wear, weight, and cost. Most
disk brakes can be locked.
ABS is intended to save your ass when there's poor traction by
preventing lock--it will also prevent lock on good surfaces but
generally isn't needed for that purpose.
> Scott Lurndal wrote:
> > On the other hand, disc brakes are designed so they don't lock up,
> > this includes the materials used as well plus the modern ABS
> > electronics.
> >
In article <[email protected]>, [email protected] says...
>
> The name "anti-lock" is a misnomer as the brakes successively lock and
> release each pulse. On each release steering control is regained. Braking
> distance is not improved as admitted in later research.
We all know how it works, and what "later research" is this that shows
that braking distance is not improved on slippery surfaces?
Every test I've seen has shown that an _expert_ driver having made a few
practice stops on the specific surface on the specific day in the
specific vehicle can beat it by a very small margin on _dry_ surfaces,
but not without practice and not on wet, icy, or other kinds of reduced-
traction surfaces.
ABS does not engage until the driver has already screwed up.
>
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> They're not "designed to lock up", they're designed as a compromise
> between maximum braking force, fade, pad wear, weight, and cost. Most
> disk brakes can be locked.
>
> ABS is intended to save your ass when there's poor traction by
> preventing lock--it will also prevent lock on good surfaces but
> generally isn't needed for that purpose.
In article <[email protected]>, [email protected] says...
>
> Sorry you asre twisting words and playing with semantics.
>
> Brake lock-up is not when the wheel stops turning. It is when the brakes
> will not let go and cease to act linearly.
>
> ABS was not created for brake lock-up. ABS would not help this problem.
Brake lockup _is_ when the wheel stops turning. What you are describing
is brakes broken.
>
>
>
> "Mike Marlow" <[email protected]> wrote in message
> news:[email protected]...
> You are correct that disk brakes have been around a lot longer than ABS has,
> but if you believe that disk brakes will not lock up then you simply need to
> drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
> Why do you think ABS exists?
>
>
> Josepi wrote:
>
> > Disc brake were around for a lot longer than the ABS systems were ever
> > implemented.
> > Disc brakes were not sdesigned to "lock up" but rather be more linear
> > than shoe brake systems, and fade less.
> >
Sorry you asre twisting words and playing with semantics.
Brake lock-up is not when the wheel stops turning. It is when the brakes
will not let go and cease to act linearly.
ABS was not created for brake lock-up. ABS would not help this problem.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
You are correct that disk brakes have been around a lot longer than ABS has,
but if you believe that disk brakes will not lock up then you simply need to
drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
Why do you think ABS exists?
Josepi wrote:
> Disc brake were around for a lot longer than the ABS systems were ever
> implemented.
> Disc brakes were not sdesigned to "lock up" but rather be more linear
> than shoe brake systems, and fade less.
>
--
-Mike-
[email protected]
Disc brake were around for a lot longer than the ABS systems were ever
implemented.
Disc brakes were not sdesigned to "lock up" but rather be more linear than
shoe brake systems, and fade less.
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
No they aren't. ABS systems are designed to prevent the wheel from locking
up, but disk brakes aren't. In fact, quite the opposite, they are designed
to lock up but rely upon the ABS to govern them so they don't.
Scott Lurndal wrote:
> On the other hand, disc brakes are designed so they don't lock up,
> this includes the materials used as well plus the modern ABS
> electronics.
>
--
-Mike-
[email protected]
[email protected] wrote:
> This is all assuming a clean blade for the proper high co-efficient
> of friction.
> Dust od sap build-up on the blade can change that very quickly.
Consider what a disk brake caliper has to overcome: dirt, water, oil,
pigeons. It still does a pretty good job.
On Sun, 17 Oct 2010 16:53:16 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 17, 5:38Â pm, Larry Jaques <[email protected]>
>wrote:
>> On Sun, 17 Oct 2010 15:01:07 -0400, [email protected] wrote:
>> >On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
>> ><[email protected]> wrote:
>> >>I was comparing efficiencies for a given number of square inches of
>> >>friction material, as noted further on in my last post. Â If you want
>> >>to cheat, go ahead, but...
>>
>> >You didn't state you were comparing area of friction material, sonI'm
>> >not cheating. Drum brakes have more friction material for the same
>> >brake diameter.
>>
>> I did, and I quote: Â "For a given poundage and square inch of pad,
>> they're better than drums."
>>
>> >And you are wrong on one other point. Disc brakes are generally
>> >accepted as being HEAVIER than drum brakes of the same size, due to
>> >the requirements of both the caliper and caliper frame vs stamped
>> >backplate of a drum brake. The drum itself, compared to the rotor, can
>> >go from being a virtual wash to the rotors being slightly lighter.
>>
>> I'm used to full-sized vehicles, and the drums outweigh the entire
>> rest of the front suspension. Â YMMV.
>>
>> >>True, and it takes, what, about one quarter -second- of applied
>> >>braking to warm them up? Â Gimme a break!
>>
>> >Can take a lot longer than that. Depending on the pad material, of
>> >course.
>>
>> Moving into racing parts, sure. Â And they're lighter still. Â I don't
>> know about you, but most people back out of their driveway and hit a
>> couple of stopsigns before they hit the freeway for a high-speed
>> braking situation. Â Those 90%+ have warm brakes before they get up to
>> speed. Â I just don't see your point at all unless it's semi-metallic
>> pads, and they take a helluva lot more force to stop, too. Whole
>> nother ball of worms and NOT standard equipment.
>>
>> --
>> Know how to listen, and you will
>> profit even from those who talk badly.
>> Â Â Â Â Â Â Â Â Â Â Â Â Â -- Plutarch
>
>All you need to do is look at the history of the disc brake.
>Lightweight, high-speed stopping power, reliable, operable in wet
>conditions... IOW...aircraft.
>On the back-end of a competition car, inboard disc brakes are often
>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
>competition drive systems, the discs are sometimes even found inboard,
>at the front-end.
>
>There simply isn't one single reason NOT to have disc brakes.
Aircraft disc brakes, particularly on light planes, are not required
to do nearly the braking an automotive brake is. The calipers are
aluminum, the 5 inch diameter discs unventilated and about 8mm thick.
And the plane (mine anyway) grosses out at well under a ton. Also, it
can land in 200 feet without even using the brakes at all.
MUCH different than the disc brakes on a car. More like a go-cart or a
bicycle. Mopeds have bigger brakes than a c172
On Oct 17, 10:57=A0pm, [email protected] wrote:
> On Sun, 17 Oct 2010 16:53:16 -0700 (PDT), Robatoy
>
>
>
>
>
> <[email protected]> wrote:
> >On Oct 17, 5:38=A0pm, Larry Jaques <[email protected]>
> >wrote:
> >> On Sun, 17 Oct 2010 15:01:07 -0400, [email protected] wrote:
> >> >On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
> >> ><[email protected]> wrote:
> >> >>I was comparing efficiencies for a given number of square inches of
> >> >>friction material, as noted further on in my last post. =A0If you wa=
nt
> >> >>to cheat, go ahead, but...
>
> >> >You didn't state you were comparing area of friction material, sonI'm
> >> >not cheating. Drum brakes have more friction material for the same
> >> >brake diameter.
>
> >> I did, and I quote: =A0 "For a given poundage and square inch of pad,
> >> they're better than drums."
>
> >> >And you are wrong on one other point. Disc brakes are generally
> >> >accepted as being HEAVIER than drum brakes of the same size, due to
> >> >the requirements of both the caliper and caliper frame vs stamped
> >> >backplate of a drum brake. The drum itself, compared to the rotor, ca=
n
> >> >go from being a virtual wash to the rotors being slightly lighter.
>
> >> I'm used to full-sized vehicles, and the drums outweigh the entire
> >> rest of the front suspension. =A0YMMV.
>
> >> >>True, and it takes, what, about one quarter -second- of applied
> >> >>braking to warm them up? =A0Gimme a break!
>
> >> >Can take a lot longer than that. Depending on the pad material, of
> >> >course.
>
> >> Moving into racing parts, sure. =A0And they're lighter still. =A0I don=
't
> >> know about you, but most people back out of their driveway and hit a
> >> couple of stopsigns before they hit the freeway for a high-speed
> >> braking situation. =A0Those 90%+ have warm brakes before they get up t=
o
> >> speed. =A0I just don't see your point at all unless it's semi-metallic
> >> pads, and they take a helluva lot more force to stop, too. Whole
> >> nother ball of worms and NOT standard equipment.
>
> >> --
> >> Know how to listen, and you will
> >> profit even from those who talk badly.
> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 -- Plutarch
>
> >All you need to do is look at the history of the disc brake.
> >Lightweight, high-speed stopping power, reliable, operable in wet
> >conditions... IOW...aircraft.
> >On the back-end of a competition car, inboard disc brakes are often
> >used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
> >competition drive systems, the discs are sometimes even found inboard,
> >at the front-end.
>
> >There simply isn't one single reason NOT to have disc brakes.
>
> =A0Aircraft disc brakes, particularly on light planes, are not required
> to do nearly the braking an automotive brake is. The calipers are
> aluminum, the 5 inch diameter discs unventilated and about 8mm thick.
> And the plane =A0(mine anyway) grosses out at well under a ton. Also, it
> can land in 200 feet without even using the brakes at all.
>
> MUCH different than the disc brakes on a car. More like a go-cart or a
> bicycle. Mopeds have bigger brakes than a c172
Did I mention little puddle jumpers like a 172? I have seen 1/4 scale
models with disc brakes....and I wasn't talking about them either.
Now read my paragraph again. I talked about the origin of the disc
brakes. period.
.
.
Josepi wrote:
> Disc brake were around for a lot longer than the ABS systems were ever
> implemented.
> Disc brakes were not sdesigned to "lock up" but rather be more linear
> than shoe brake systems, and fade less.
>
You are correct that disk brakes have been around a lot longer than ABS has,
but if you believe that disk brakes will not lock up then you simply need to
drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
Why do you think ABS exists?
--
-Mike-
[email protected]
On Thu, 14 Oct 2010 06:08:55 -0700, Larry Jaques
<[email protected]> wrote:
>On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
><[email protected]> wrote:
>
>>[email protected] wrote:
>>> On Wed, 13 Oct 2010 22:52:34 -0400, "Josepi" <[email protected]>
>>> wrote:
>>>
>>>> As I stated posters seem to lean towards the technology they are
>>>> comfortable with.
>>>>
>>>> The mechanics would be a nightmare to me, also. To others the
>>>> electronics would be a nightmare.
>>>>
>>>> Contactor and resistor?...way too complicated.
>>>>
>>>>
>>>> <[email protected]> wrote in message
>>>> news:[email protected]...
>>>> You want to put that monstrosity on a tilting arbour saw, mounted
>>>> under the saw table and in the path of the saw-dust and have it work
>>>> reliably???
>>>> Not going to happen - guaranteed.
>>>>
>>> It's BECAUSE I was a mechanic for several decades that I would NOT use
>>> a brake caliper for the application.
>>
>>As a guy who has done all of his own vehicle maintenance for 40 years now, I
>>have to ask what you observed in your experiences, that causes you to make
>>this statement? I don't know if the brake caliper idea is the most elegant
>>solution, but I sure can't see anything in what you are saying that would
>>suggest it is not a workable solution.
>
>Suitable placement of an air nozzle tube to clear the caliper frame
>every hour or so would go far into making this device work for more
>than an hour. You'd have to keep the sawdust from piercing the seals
>and/or building up on the frame
Which just adds more complexity, reducing the reliability beyond the
acceptable (at least for mr) level.
Scott Lurndal wrote:
>
> On the other hand, disc brakes are designed so they don't lock up,
> this includes the materials used as well plus the modern ABS
> electronics.
>
No they aren't. ABS systems are designed to prevent the wheel from locking
up, but disk brakes aren't. In fact, quite the opposite, they are designed
to lock up but rely upon the ABS to govern them so they don't.
--
-Mike-
[email protected]
Ahhhh. The troll leader of the gang speaks.
"Everybody has to be just like me"
Better listen up or you will anger the biggest troll.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
On 10/19/10 7:30 PM, Doug Miller wrote:
> In article<[email protected]>, [email protected]
> wrote:
>> On 10/18/10 7:57 PM, Doug Miller wrote:
>>> In article<[email protected]>,
>>> [email protected]
>> wrote:
>>>> On 10/18/10 12:38 PM, Josepi wrote:
>>>>> Always a trolling angle.
>>>>>
>>>>> "-MIKE-"<[email protected]> wrote in message
>>>>> news:[email protected]...
>>>>> Are you going to at least give credit to the websites from which you
>>>>> cut-n-pasted all this?
>>>>>
>>>>
>>>> Trolling? Really? That's how you see it?
>>>> Where I come from copying someone else's work and passing it off as
>>>> your
>>>> own is called plagiarism.
>>>>
>>>> Passive aggressive, much, Josepi? :-)
>>>
>>> PDFTFT
>>
>> Nobody's forcing you to read it.
>>
> Problem is that I have him killfiled, but not you. It's kinda
> disappointing to
> open one of *your* posts, and see a bunch of *his* drivel.
Kill file me, then... or get some bigger problems in your life. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
Always a trolling angle.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Are you going to at least give credit to the websites from which you
cut-n-pasted all this?
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
Bullshit. Where you come from, and most others, coying somebody else's work
is called a "Reference"
Constantly disputing anything and everything for a response that isn't
related to the subject at hand is called.... "Trolling"
You don't want to discuss anything at hand, you just want attention and
defences.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Trolling? Really? That's how you see it?
Where I come from copying someone else's work and passing it off as your
own is called plagiarism.
Passive aggressive, much, Josepi? :-)
In article <[email protected]>,
[email protected] says...
>
> On 10/19/10 8:50 PM, Josepi wrote:
> > Bullshit. Where you come from, and most others, coying somebody else's work
> > is called a "Reference"
> >
>
> I'm assuming you at least got though middle school where the subject was
> covered, but here's a refresher...
> Giving CREDIT to the original author is called a reference.
> Copying and pasting word for word without giving credit to the author is
> plagiarism.
Whether you give credit or not, it's copyright violation unless you have
the permission of the copyright holder or it falls under one of the
"fair use" exceptions.
There is for some reason a persistent notion that using someone else's
work is lawful as long as you give credit. It is not.
> > Constantly disputing anything and everything for a response that isn't
> > related to the subject at hand is called.... "Trolling"
> >
>
> Thanks for finally admitting it.
>
>
> > You don't want to discuss anything at hand, you just want attention and
> > defences.
>
> Even if that were true, at least I use my own material.
On Sun, 17 Oct 2010 22:59:03 -0400, [email protected] wrote:
>On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
>wrote:
>
>>Rust on the back disks from lack of heavy usage.
>>
>>I doubt it would be oak rust, though.
>>
>>
>>"Robatoy" <[email protected]> wrote in message
>>news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com...
>>All you need to do is look at the history of the disc brake.
>>Lightweight, high-speed stopping power, reliable, operable in wet
>>conditions... IOW...aircraft.
And you are WRONG again, Robotoy.
Disc brakes were invented before flight.
The drum brake, as it is now known, became all-dominant in the United
States. In Europe, particularly in Great Britain, it had to share the
stage with disc brakes. Disc brakes became more or less standard on
European cars during the '50s, about 20 years before they were adopted
by American manufacturers in 1973.
This is ironic, because the spot-type disc brake is an American
invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
electric car having front-wheel disc brakes.
He made a large disc integral with the hub on each wheel.
Electromagnets were used to press smaller discs, lined with a friction
material, against spots on the rotating disc to bring the wheel to a
stop. Springs retracted the spot discs when current was interrupted.
Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
Lanchester for a nonelectric spot disc braking system that's similar
in principle to what we have today. The biggest problem that
Lanchester encountered was noise. Metal-to-metal contact between his
copper linings and the metal disc caused an intense screech that sent
chills through anyone within earshot.
The problem was solved in 1907 when Herbert Frood, another Englishman,
came up with the idea of lining pads with asbestos. The new material
was quickly adopted by car manufacturers on both drum and disc brakes.
Asbestos linings also outlasted other friction materials by a wide
margin. The 10,000-mile brake job had arrived.
As roads improved and cars began to be driven at high speeds,
manufacturers recognized the need for even greater braking power. One
solution to the problem became apparent during the Elgin road Race of
1915. A Duesenberg took the flats at 80 mph, then screeched to a
virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
such magnificent braking power was to simply use an internal brake on
each front wheel as well as each rear wheel.
In 1918, a young inventor named Malcolm Lougheed (who later changed
the spelling of his name to Lockheed) applied hydraulics to braking.
He used cylinders and tubes to transmit fluid pressure against brake
shoes, pushing the shoes against the drums. In 1921, the first
passenger car to be equipped with four-wheel hydraulic brakes appeared
-- the Model A Duesenberg.
Carmakers as a group were not quick to adopt hydraulics. Ten years
after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
the others still had cable-operated mechanical brakes. In fact, it was
not until 1939 that Ford finally gave in, becoming the last major
manufacturer to switch to hydraulic brakes.
The basic braking system we have today was pretty much in place by
1921, including a refinement some regard as contemporary -- power
assist.
Power assist, technically, dates back to 1903 when a car called the
Tincher used air brakes. But the first car to be equipped with a
vacuum-operated power booster similar to those we have today was the
1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
the physical effort needed to apply brakes. Vacuum boosters from then
to now have similar designs.
The first widespread deviation from vacuum power assist came about in
1985. Some '85 GM cars use an electrically driven brake booster, which
is smaller and lighter than the conventional vacuum booster, giving an
all-hydraulic system. Some cars with antilock brakes also use
all-hydraulic systems.
The first car to have self-adjusting brakes was the 1925 Cole. The
prototype for today's systems appeared on the 1946 Studebaker. The
mechanism by Wagner Electric Co., consisted of an adjusting wedge
under the influence of a tension spring. As linings wore, a plug
receded to move a pin and lever against the spring. This forced the
adjusting wedge against brake shoes, which expanded to keep linings at
a preset distance from the drums.
As for the antilock (antiskid) units now available in the U.S., they
are hardly new. The first practical antiskid braking system, named
Maxaret, was developed in 1958 by the Road Research Laboratories in
Great Britain and was first applied to the Jensen FF sports sedan in
1966.
Three years later, in 1969, the Lincoln Continental Mark III was
equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
Sensors on the rear wheels transmitted signals to a transistorized
"computer" behind the glove box. The computer controlled a
vacuum-operated valve on the rear brake line to modulate pressure to
the rear brakes when the sensors told the computer that the brakes
were locking.
Cost and some technical problems caused the shelving of this unit. But
now, updated versions that give four-wheel skid control are offered on
almost every car model, although initially they were available only on
high-end cars like Lincoln and Mercedes, and a few European cars.
Computerized brakes notwithstanding, there is a piece of advice about
using brakes that's as relevant today as it was in 1909 when it was
first published in The American Cyclopedia of the Automobile:
"Good driving in traffic is shown by making the minimum use of brakes.
The strain on passengers amounts to intense nervousness when the car
is constantly driven so that the least alteration of direction or of
pace on the part of any vehicle ahead results in the violent
application of the brake."
And so it will always be.
>>On the back-end of a competition car, inboard disc brakes are often
>>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
>>competition drive systems, the discs are sometimes even found inboard,
>>at the front-end.
>>
>>There simply isn't one single reason NOT to have disc brakes.
>>
> There were even a few inboard DRUM brake vehicles built. Front drive
>too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??
<[email protected]> wrote:
>>
> The KEB CombiBrake is a drum brake that fits NemaC motors - on the
> drive end.
> A nice homemade drum brake for a dual shaft motor in April 1955 Pop
> Mech too. (Page 205 - shop notes))
------------------------------------
Never saw one in the marketplace, certainly never had to compete
against one, which says something about it's commercial viability.
Many things, including me, have changed since 1955, the year of my
high school graduation.
Lew
On Tue, 19 Oct 2010 21:19:43 -0700, "Lew Hodgett"
<[email protected]> wrote:
>Somebody wrote:
>
>> There AREelectric motors that DO have a drum brake on the fan
>> (opposite the drive ) end of the motor. They COULD be used on a
>> table
>> saw.
>----------------------------------
>Not in the 20 years I sold brake motors.
>
>Dings was the primary supplier of disk brakes to most of the motor
>manufacturers.
>
>Lew
>
The KEB CombiBrake is a drum brake that fits NemaC motors - on the
drive end.
A nice homemade drum brake for a dual shaft motor in April 1955 Pop
Mech too. (Page 205 - shop notes))
On Oct 18, 1:23=A0pm, [email protected] wrote:
> On Sun, 17 Oct 2010 22:59:03 -0400, [email protected] wrote:
> >On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
> >wrote:
>
> >>Rust on the back disks from lack of heavy usage.
>
> >>I doubt it would be oak rust, though.
>
> >>"Robatoy" <[email protected]> wrote in message
> >>news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com.=
..
> >>All you need to do is look at the history of the disc brake.
> >>Lightweight, high-speed stopping power, reliable, operable in wet
> >>conditions... IOW...aircraft.
>
> =A0And you are WRONG again, Robotoy.
> Disc brakes were invented before flight.
>
> The drum brake, as it is now known, became all-dominant in the United
> States. In Europe, particularly in Great Britain, it had to share the
> stage with disc brakes. Disc brakes became more or less standard on
> European cars during the '50s, about 20 years before they were adopted
> by American manufacturers in 1973.
>
> This is ironic, because the spot-type disc brake is an American
> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
> electric car having front-wheel disc brakes.
>
> He made a large disc integral with the hub on each wheel.
> Electromagnets were used to press smaller discs, lined with a friction
> material, against spots on the rotating disc to bring the wheel to a
> stop. Springs retracted the spot discs when current was interrupted.
>
> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
> Lanchester for a nonelectric spot disc braking system that's similar
> in principle to what we have today. The biggest problem that
> Lanchester encountered was noise. Metal-to-metal contact between his
> copper linings and the metal disc caused an intense screech that sent
> chills through anyone within earshot.
>
> The problem was solved in 1907 when Herbert Frood, another Englishman,
> came up with the idea of lining pads with asbestos. The new material
> was quickly adopted by car manufacturers on both drum and disc brakes.
> Asbestos linings also outlasted other friction materials by a wide
> margin. The 10,000-mile brake job had arrived.
>
> As roads improved and cars began to be driven at high speeds,
> manufacturers recognized the need for even greater braking power. One
> solution to the problem became apparent during the Elgin road Race of
> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
> such magnificent braking power was to simply use an internal brake on
> each front wheel as well as each rear wheel.
>
> In 1918, a young inventor named Malcolm Lougheed (who later changed
> the spelling of his name to Lockheed) applied hydraulics to braking.
> He used cylinders and tubes to transmit fluid pressure against brake
> shoes, pushing the shoes against the drums. In 1921, the first
> passenger car to be equipped with four-wheel hydraulic brakes appeared
> -- the Model A Duesenberg.
>
> Carmakers as a group were not quick to adopt hydraulics. Ten years
> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
> the others still had cable-operated mechanical brakes. In fact, it was
> not until 1939 that Ford finally gave in, becoming the last major
> manufacturer to switch to hydraulic brakes.
>
> The basic braking system we have today was pretty much in place by
> 1921, including a refinement some regard as contemporary -- power
> assist.
>
> Power assist, technically, dates back to 1903 when a car called the
> Tincher used air brakes. But the first car to be equipped with a
> vacuum-operated power booster similar to those we have today was the
> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
> the physical effort needed to apply brakes. Vacuum boosters from then
> to now have similar designs.
>
> The first widespread deviation from vacuum power assist came about in
> 1985. Some '85 GM cars use an electrically driven brake booster, which
> is smaller and lighter than the conventional vacuum booster, giving an
> all-hydraulic system. Some cars with antilock brakes also use
> all-hydraulic systems.
>
> The first car to have self-adjusting brakes was the 1925 Cole. The
> prototype for today's systems appeared on the 1946 Studebaker. The
> mechanism by Wagner Electric Co., consisted of an adjusting wedge
> under the influence of a tension spring. As linings wore, a plug
> receded to move a pin and lever against the spring. This forced the
> adjusting wedge against brake shoes, which expanded to keep linings at
> a preset distance from the drums.
>
> As for the antilock (antiskid) units now available in the U.S., they
> are hardly new. The first practical antiskid braking system, named
> Maxaret, was developed in 1958 by the Road Research Laboratories in
> Great Britain and was first applied to the Jensen FF sports sedan in
> 1966.
>
> Three years later, in 1969, the Lincoln Continental Mark III was
> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
> Sensors on the rear wheels transmitted signals to a transistorized
> "computer" behind the glove box. The computer controlled a
> vacuum-operated valve on the rear brake line to modulate pressure to
> the rear brakes when the sensors told the computer that the brakes
> were locking.
>
> Cost and some technical problems caused the shelving of this unit. But
> now, updated versions that give four-wheel skid control are offered on
> almost every car model, although initially they were available only on
> high-end cars like Lincoln and Mercedes, and a few European cars.
>
> Computerized brakes notwithstanding, there is a piece of advice about
> using brakes that's as relevant today as it was in 1909 when it was
> first published in The American Cyclopedia of the Automobile:
>
> "Good driving in traffic is shown by making the minimum use of brakes.
> The strain on passengers amounts to intense nervousness when the car
> is constantly driven so that the least alteration of direction or of
> pace on the part of any vehicle ahead results in the violent
> application of the brake."
>
> And so it will always be.
>
>
>
> >>On the back-end of a competition car, inboard disc brakes are often
> >>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
> >>competition drive systems, the discs are sometimes even found inboard,
> >>at the front-end.
>
> >>There simply isn't one single reason NOT to have disc brakes.
>
> > There were even a few inboard DRUM brake vehicles built. Front drive
> >too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??
How does that make me wrong? Are you telling me that disc brakes are
not the preferred system for aircraft for all those reasons I laid
out? That it wasn't the aircraft people who developed many facets of
those systems?
Tell you what..... there was a guy in my home-town in Holland who tied
his 1930-sh Somethingmobile to a tree with a rope so it wouldn't roll
down his laneway. Now I suppose you will give me a dissertation on
rope-brake systems through the frikkin' ages as well? What about
parachute brakes? There are all kinds of people using those. The
Veyron uses a big paddle that rises out of the back of the car to
assist slowing the thing down.
Anywhooo.. disc brakes are the preferred systems regardless whether or
not the Queen's carriage has a leather pad rubbing on the tyres.
On 10/18/10 12:23 PM, [email protected] wrote:
> And you are WRONG again, Robotoy.
> Disc brakes were invented before flight.
>
> The drum brake, as it is now known, became all-dominant in the United
> States. In Europe, particularly in Great Britain, it had to share the
> stage with disc brakes. Disc brakes became more or less standard on
> European cars during the '50s, about 20 years before they were adopted
> by American manufacturers in 1973.
>
> This is ironic, because the spot-type disc brake is an American
> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
> electric car having front-wheel disc brakes.
>
> He made a large disc integral with the hub on each wheel.
> Electromagnets were used to press smaller discs, lined with a friction
> material, against spots on the rotating disc to bring the wheel to a
> stop. Springs retracted the spot discs when current was interrupted.
>
> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
> Lanchester for a nonelectric spot disc braking system that's similar
> in principle to what we have today. The biggest problem that
> Lanchester encountered was noise. Metal-to-metal contact between his
> copper linings and the metal disc caused an intense screech that sent
> chills through anyone within earshot.
>
> The problem was solved in 1907 when Herbert Frood, another Englishman,
> came up with the idea of lining pads with asbestos. The new material
> was quickly adopted by car manufacturers on both drum and disc brakes.
> Asbestos linings also outlasted other friction materials by a wide
> margin. The 10,000-mile brake job had arrived.
>
> As roads improved and cars began to be driven at high speeds,
> manufacturers recognized the need for even greater braking power. One
> solution to the problem became apparent during the Elgin road Race of
> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
> such magnificent braking power was to simply use an internal brake on
> each front wheel as well as each rear wheel.
>
> In 1918, a young inventor named Malcolm Lougheed (who later changed
> the spelling of his name to Lockheed) applied hydraulics to braking.
> He used cylinders and tubes to transmit fluid pressure against brake
> shoes, pushing the shoes against the drums. In 1921, the first
> passenger car to be equipped with four-wheel hydraulic brakes appeared
> -- the Model A Duesenberg.
>
> Carmakers as a group were not quick to adopt hydraulics. Ten years
> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
> the others still had cable-operated mechanical brakes. In fact, it was
> not until 1939 that Ford finally gave in, becoming the last major
> manufacturer to switch to hydraulic brakes.
>
> The basic braking system we have today was pretty much in place by
> 1921, including a refinement some regard as contemporary -- power
> assist.
>
> Power assist, technically, dates back to 1903 when a car called the
> Tincher used air brakes. But the first car to be equipped with a
> vacuum-operated power booster similar to those we have today was the
> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
> the physical effort needed to apply brakes. Vacuum boosters from then
> to now have similar designs.
>
> The first widespread deviation from vacuum power assist came about in
> 1985. Some '85 GM cars use an electrically driven brake booster, which
> is smaller and lighter than the conventional vacuum booster, giving an
> all-hydraulic system. Some cars with antilock brakes also use
> all-hydraulic systems.
>
> The first car to have self-adjusting brakes was the 1925 Cole. The
> prototype for today's systems appeared on the 1946 Studebaker. The
> mechanism by Wagner Electric Co., consisted of an adjusting wedge
> under the influence of a tension spring. As linings wore, a plug
> receded to move a pin and lever against the spring. This forced the
> adjusting wedge against brake shoes, which expanded to keep linings at
> a preset distance from the drums.
>
> As for the antilock (antiskid) units now available in the U.S., they
> are hardly new. The first practical antiskid braking system, named
> Maxaret, was developed in 1958 by the Road Research Laboratories in
> Great Britain and was first applied to the Jensen FF sports sedan in
> 1966.
>
> Three years later, in 1969, the Lincoln Continental Mark III was
> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
> Sensors on the rear wheels transmitted signals to a transistorized
> "computer" behind the glove box. The computer controlled a
> vacuum-operated valve on the rear brake line to modulate pressure to
> the rear brakes when the sensors told the computer that the brakes
> were locking.
>
> Cost and some technical problems caused the shelving of this unit. But
> now, updated versions that give four-wheel skid control are offered on
> almost every car model, although initially they were available only on
> high-end cars like Lincoln and Mercedes, and a few European cars.
>
> Computerized brakes notwithstanding, there is a piece of advice about
> using brakes that's as relevant today as it was in 1909 when it was
> first published in The American Cyclopedia of the Automobile:
>
> "Good driving in traffic is shown by making the minimum use of brakes.
> The strain on passengers amounts to intense nervousness when the car
> is constantly driven so that the least alteration of direction or of
> pace on the part of any vehicle ahead results in the violent
> application of the brake."
>
> And so it will always be.
>
Are you going to at least give credit to the websites from which you
cut-n-pasted all this?
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/18/10 12:38 PM, Josepi wrote:
> Always a trolling angle.
>
> "-MIKE-"<[email protected]> wrote in message
> news:[email protected]...
> Are you going to at least give credit to the websites from which you
> cut-n-pasted all this?
>
Trolling? Really? That's how you see it?
Where I come from copying someone else's work and passing it off as your
own is called plagiarism.
Passive aggressive, much, Josepi? :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, [email protected] wrote:
>On 10/18/10 12:38 PM, Josepi wrote:
>> Always a trolling angle.
>>
>> "-MIKE-"<[email protected]> wrote in message
>> news:[email protected]...
>> Are you going to at least give credit to the websites from which you
>> cut-n-pasted all this?
>>
>
>Trolling? Really? That's how you see it?
>Where I come from copying someone else's work and passing it off as your
>own is called plagiarism.
>
>Passive aggressive, much, Josepi? :-)
PDFTFT
On 10/18/10 7:57 PM, Doug Miller wrote:
> In article<[email protected]>, [email protected] wrote:
>> On 10/18/10 12:38 PM, Josepi wrote:
>>> Always a trolling angle.
>>>
>>> "-MIKE-"<[email protected]> wrote in message
>>> news:[email protected]...
>>> Are you going to at least give credit to the websites from which you
>>> cut-n-pasted all this?
>>>
>>
>> Trolling? Really? That's how you see it?
>> Where I come from copying someone else's work and passing it off as your
>> own is called plagiarism.
>>
>> Passive aggressive, much, Josepi? :-)
>
> PDFTFT
Nobody's forcing you to read it.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, [email protected] wrote:
>On 10/18/10 7:57 PM, Doug Miller wrote:
>> In article<[email protected]>, [email protected]
> wrote:
>>> On 10/18/10 12:38 PM, Josepi wrote:
>>>> Always a trolling angle.
>>>>
>>>> "-MIKE-"<[email protected]> wrote in message
>>>> news:[email protected]...
>>>> Are you going to at least give credit to the websites from which you
>>>> cut-n-pasted all this?
>>>>
>>>
>>> Trolling? Really? That's how you see it?
>>> Where I come from copying someone else's work and passing it off as your
>>> own is called plagiarism.
>>>
>>> Passive aggressive, much, Josepi? :-)
>>
>> PDFTFT
>
>Nobody's forcing you to read it.
>
Problem is that I have him killfiled, but not you. It's kinda disappointing to
open one of *your* posts, and see a bunch of *his* drivel.
On 10/19/10 7:30 PM, Doug Miller wrote:
> In article<[email protected]>, [email protected] wrote:
>> On 10/18/10 7:57 PM, Doug Miller wrote:
>>> In article<[email protected]>, [email protected]
>> wrote:
>>>> On 10/18/10 12:38 PM, Josepi wrote:
>>>>> Always a trolling angle.
>>>>>
>>>>> "-MIKE-"<[email protected]> wrote in message
>>>>> news:[email protected]...
>>>>> Are you going to at least give credit to the websites from which you
>>>>> cut-n-pasted all this?
>>>>>
>>>>
>>>> Trolling? Really? That's how you see it?
>>>> Where I come from copying someone else's work and passing it off as your
>>>> own is called plagiarism.
>>>>
>>>> Passive aggressive, much, Josepi? :-)
>>>
>>> PDFTFT
>>
>> Nobody's forcing you to read it.
>>
> Problem is that I have him killfiled, but not you. It's kinda disappointing to
> open one of *your* posts, and see a bunch of *his* drivel.
Kill file me, then... or get some bigger problems in your life. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/19/10 8:50 PM, Josepi wrote:
> Bullshit. Where you come from, and most others, coying somebody else's work
> is called a "Reference"
>
I'm assuming you at least got though middle school where the subject was
covered, but here's a refresher...
Giving CREDIT to the original author is called a reference.
Copying and pasting word for word without giving credit to the author is
plagiarism.
> Constantly disputing anything and everything for a response that isn't
> related to the subject at hand is called.... "Trolling"
>
Thanks for finally admitting it.
> You don't want to discuss anything at hand, you just want attention and
> defences.
Even if that were true, at least I use my own material.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/20/10 4:08 AM, J. Clarke wrote:
> In article<[email protected]>,
> [email protected] says...
>>
>> On 10/19/10 8:50 PM, Josepi wrote:
>>> Bullshit. Where you come from, and most others, coying somebody else's work
>>> is called a "Reference"
>>>
>>
>> I'm assuming you at least got though middle school where the subject was
>> covered, but here's a refresher...
>> Giving CREDIT to the original author is called a reference.
>> Copying and pasting word for word without giving credit to the author is
>> plagiarism.
>
> Whether you give credit or not, it's copyright violation unless you have
> the permission of the copyright holder or it falls under one of the
> "fair use" exceptions.
>
> There is for some reason a persistent notion that using someone else's
> work is lawful as long as you give credit. It is not.
>
The copyright aspect really wasn't the point.
Someone in here once used the term, "Googlectual."
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
The name "anti-lock" is a misnomer as the brakes successively lock and
release each pulse. On each release steering control is regained. Braking
distance is not improved as admitted in later research.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
They're not "designed to lock up", they're designed as a compromise
between maximum braking force, fade, pad wear, weight, and cost. Most
disk brakes can be locked.
ABS is intended to save your ass when there's poor traction by
preventing lock--it will also prevent lock on good surfaces but
generally isn't needed for that purpose.
On 10/15/10 12:31 PM, Josepi wrote:
> Sorry you asre twisting words and playing with semantics.
>
You mean, like this,
"The name "anti-lock" is a misnomer as the brakes successively lock and
release each pulse."
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Wed, 13 Oct 2010 18:34:56 -0400, Bill <[email protected]> wrote:
>J. Clarke wrote:
>> In article<[email protected]>, [email protected] says...
>>>
>>> J. Clarke wrote:
>>>
>>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>>>>> my '76 Lincoln might surprise you.
>>>>>>>>
>>>>>>> Bill>
>>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>
>>>>>> J. Clarke>
>>>>>> Why would something that can stop a 4000 pound car "snap" when called on
>>>>>> to stop a 3 pound saw blade?
>>>
>>>>> Bill>
>>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>>>
>>> >J. Clarke>
>>>> To stop the saw in a fraction of a revolution, you need rapid
>>>> application. A pyro will build pressure rapidly.
>>>
>>> That is what I what I might expect to increase the probability of failure.
>>>
>>> Given blade radius and density, and rpm, you could probably integrate to
>>> compute the (foot-pounds of) energy that need to be stopped in a small
>>> fraction of a second (I hope that the dust on the blade won't be an
>>> issue). :) I've seen you post in another "forum" so I believe you are
>>> up to the calculation. I do not have engineering background to back me
>>> up, I'm just thinking it through with you and everyone else who is
>>> reading. Evidently, you'll need to generate the equivalent of an equal
>>> and opposite amount of energy. This means, I think, that you only get
>>> the benefit of a "projection" (dot product) and not all of the force you
>>> can apply to the side of the blade. My reasoning could definitely be
>>> off, maybe a physicist or engineer could help out?
>>
>> Disk brakes work by friction. The energy comes off as heat. Apply F to
>> the brake, k * F is the braking force where k is the coefficient of
>> friction.
>>
>> Back of the envelope it looks like the Lincoln brake at Lincoln pressure
>> can stop it in about 1/3 revolution. Don't know how much higher
>> pressure that caliper can take--at 2x the pressure might be able to do
>> it in 1/6 revolution, which puts it in Sawstop territory.
>>
>Interesting. Thank you. I'm not sure about your "imposter"..
>
>Bill
This is all assuming a clean blade for the proper high co-efficient
of friction.
Dust od sap build-up on the blade can change that very quickly.
In article <[email protected]>,
[email protected] says...
>
> On Sun, 17 Oct 2010 12:07:01 -0700 (PDT), Robatoy
> <[email protected]> wrote:
>
> >On Oct 17, 2:43 pm, [email protected] wrote:
> >
> >>
> >> I've driven an X1/9 too -
> >
> >Who would ADMIT to such a thing.....?
> I didn't say I OWNED it.
> I drove it for a while after replacing the engine with the brand new
> engine out of the 128S I converted to electric power.
> Got the 128S for doing the transplant, so I wasn't complaining.
Hey, I owned one and loved it until some asshole stole it.
In article <[email protected]>, "J. Clarke" <[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Sun, 17 Oct 2010 12:07:01 -0700 (PDT), Robatoy
>> <[email protected]> wrote:
>>
>> >On Oct 17, 2:43 pm, [email protected] wrote:
>> >
>> >>
>> >> I've driven an X1/9 too -
>> >
>> >Who would ADMIT to such a thing.....?
>> I didn't say I OWNED it.
>> I drove it for a while after replacing the engine with the brand new
>> engine out of the 128S I converted to electric power.
>> Got the 128S for doing the transplant, so I wasn't complaining.
>
>Hey, I owned one and loved it until some asshole stole it.
Not the most reliable car I've ever owned (not the least, either), but hands
down the most fun to drive.
On Sun, 17 Oct 2010 12:07:01 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 17, 2:43 pm, [email protected] wrote:
>
>>
>> I've driven an X1/9 too -
>
>Who would ADMIT to such a thing.....?
Ex-Yugo and Chebby drivers, perhaps?
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
On Sun, 17 Oct 2010 12:07:01 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 17, 2:43Â pm, [email protected] wrote:
>
>>
>> I've driven an X1/9 too -
>
>Who would ADMIT to such a thing.....?
I didn't say I OWNED it.
I drove it for a while after replacing the engine with the brand new
engine out of the 128S I converted to electric power.
Got the 128S for doing the transplant, so I wasn't complaining.
OMG! Now we need to put an ABS system on our saw brake so it doesn't cause
any arbor damge from stopping to quickly?
LOL
"Scott Lurndal" <[email protected]> wrote in message
news:[email protected]...
On the other hand, disc brakes are designed so they don't lock up,
this includes the materials used as well plus the modern ABS electronics.
scott
"HeyBub" <[email protected]> writes:
>[email protected] wrote:
>> This is all assuming a clean blade for the proper high co-efficient
>> of friction.
>> Dust od sap build-up on the blade can change that very quickly.
>
>Consider what a disk brake caliper has to overcome: dirt, water, oil,
>pigeons. It still does a pretty good job.
>
On Thu, 14 Oct 2010 08:27:07 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Wed, 13 Oct 2010 23:15:27 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>> >In article <[email protected]>,
>> >[email protected] says...
>> >>
>> >> On Wed, 13 Oct 2010 18:15:40 -0400, "J. Clarke"
>> >> <[email protected]> wrote:
>> >>
>> >> >In article <[email protected]>,
>> >> >[email protected] says...
>> >> >>
>> >> >> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> >> >> <[email protected]> wrote:
>> >> >>
>> >> >> >In article <[email protected]>,
>> >> >> >[email protected] says...
>> >> >> >>
>> >> >> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>> >> >> >>
>> >> >> >> >J. Clarke wrote:
>> >> >> >> >> In article<[email protected]>, [email protected] says...
>> >> >> >> >>>
>> >> >> >> >>> I would think that an emergency stop mechanism would be a whole different
>> >> >> >> >>> magnitude than a scheduled, everyday, stop.
>> >> >> >> >>>
>> >> >> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
>> >> >> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> >> >> >> >>> would be OK too. These two situations would require different tactics.
>> >> >> >> >>>
>> >> >> >> >>> A dynamic electronic brake could vary the intensity for the two different
>> >> >> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> >> >> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> >> >> >> >>> replaced frequently.
>> >> >> >> >>
>> >> >> >> >> So how much power do you have to put into that electronic brake to stop
>> >> >> >> >> the blade as fast as Sawstop's physical block?
>> >> >> >> >>
>> >> >> >> >> And why would a caliper not last long? A set of brake pads on a car
>> >> >> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> >> >> >> >> a lot more of a workout that they would stopping a little bitty saw
>> >> >> >> >> blade that masses less than 1/1000 as much.
>> >> >> >> >
>> >> >> >> >The physics on that seem interesting. A little like stopping a speeding
>> >> >> >> >bullet on a dime--it challenges my imagination. Probably not quite as
>> >> >> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
>> >> >> >> >either.
>> >> >> >> >
>> >> >> >> >Bill
>> >> >> >> No way a caliper could stop the blade in even 4X the time the
>> >> >> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> >> >> >> the blade would be quite problematic - with dust decreasing the
>> >> >> >> stopping efficiency by a very large margin.
>> >> >> >
>> >> >> >I suspect that a small pyrotechnic pressurizing one of the calipers off
>> >> >> >my '76 Lincoln might surprise you.
>> >> >> >
>> >> >> But would also be totally impractical on a 10" saw.
>> >> >
>> >> >Why would it be "impractical on a 10" saw? The brake rotors on that car
>> >> >are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
>> >> >15" wheel.
>> >> >
>> >> You want to put that monstrosity on a tilting arbour saw, mounted
>> >> under the saw table and in the path of the saw-dust and have it work
>> >> reliably???
>> >> Not going to happen - guaranteed.
>> >
>> >It works reliably on a tilting Lincoln wheel in the path of rain, road
>> >dust, and whatever else mother nature can throw at it, so why does a
>> >nice, dry saw cabinet present such problems?
>> >
>> >Do yourself a favor, pull a wheel off your car and _look_ at the
>> >mechanism.
>> >
>> I've been doing it for over 45 years
>> I've also rebuilt a few tilting arbour saws - both belt drive, gear
>> drive, and direct drive..
>
>And yet you see a problem.
>
Most definitely.
"HeyBub" <[email protected]> writes:
>[email protected] wrote:
>> This is all assuming a clean blade for the proper high co-efficient
>> of friction.
>> Dust od sap build-up on the blade can change that very quickly.
>
>Consider what a disk brake caliper has to overcome: dirt, water, oil,
>pigeons. It still does a pretty good job.
>
On the other hand, disc brakes are designed so they don't lock up,
this includes the materials used as well plus the modern ABS electronics.
scott
On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
wrote:
>Rust on the back disks from lack of heavy usage.
>
>I doubt it would be oak rust, though.
>
>
>"Robatoy" <[email protected]> wrote in message
>news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com...
>All you need to do is look at the history of the disc brake.
>Lightweight, high-speed stopping power, reliable, operable in wet
>conditions... IOW...aircraft.
>On the back-end of a competition car, inboard disc brakes are often
>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
>competition drive systems, the discs are sometimes even found inboard,
>at the front-end.
>
>There simply isn't one single reason NOT to have disc brakes.
>
There were even a few inboard DRUM brake vehicles built. Front drive
too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??
Have you seen the videos and live demonstration? It does no harm.
They wouldn't be selling like hotcakes if their marketing strategy
centered around "losing only a pint of blood, instead of a whole finger."
Have you seen the video demonstrations? They've been done with lunch
meat and human fingers.
> 17 teeth?
>
> How fast can you push your finger?
>
> "-MIKE-"<[email protected]> wrote in message
>
> That may be true, but they still don't do any harm.
>
>> Sawstop stops the blade in 1/200 of a second, according to their Web
>> site. At 3450 RPM that means the blade stops in .29 revolution, which
>> with a 60 tooth blade means that 17 teeth have had a shot at your
>> finger.
>>
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/12/2010 11:04 AM, -MIKE- wrote:
> Have you seen the videos and live demonstration? It does no harm.
> They wouldn't be selling like hotcakes if their marketing strategy
> centered around "losing only a pint of blood, instead of a whole finger."
> Have you seen the video demonstrations? They've been done with lunch
> meat and human fingers.
>
>> 17 teeth?
>>
>> How fast can you push your finger?
>>
>> "-MIKE-"<[email protected]> wrote in message
>>
>> That may be true, but they still don't do any harm.
>>
>>> Sawstop stops the blade in 1/200 of a second, according to their Web
>>> site. At 3450 RPM that means the blade stops in .29 revolution, which
>>> with a 60 tooth blade means that 17 teeth have had a shot at your
>>> finger.
And with a 60-tooth blade spinning at 3450 RPM, that's 3450 teeth spinning past
every *second*. At that speed, coming to a dead stop after only 17 teeth have
had a chance to cut anything is pretty damn good. Unless you're just flat-out
careless or stupid (or both) and are wildly advancing your fingers towards the
blade, 17 teeth are not going to do much damage. I could do much worse in the
blink of an eye with a careless swipe of my pocketknife.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/12/10 11:21 AM, Steve Turner wrote:
> On 10/12/2010 11:04 AM, -MIKE- wrote:
>> Have you seen the videos and live demonstration? It does no harm.
>> They wouldn't be selling like hotcakes if their marketing strategy
>> centered around "losing only a pint of blood, instead of a whole finger."
>> Have you seen the video demonstrations? They've been done with lunch
>> meat and human fingers.
>>
>>> 17 teeth?
>>>
>>> How fast can you push your finger?
>>>
>>> "-MIKE-"<[email protected]> wrote in message
>>>
>>> That may be true, but they still don't do any harm.
>>>
>>>> Sawstop stops the blade in 1/200 of a second, according to their Web
>>>> site. At 3450 RPM that means the blade stops in .29 revolution, which
>>>> with a 60 tooth blade means that 17 teeth have had a shot at your
>>>> finger.
>
> And with a 60-tooth blade spinning at 3450 RPM, that's 3450 teeth
> spinning past every *second*. At that speed, coming to a dead stop after
> only 17 teeth have had a chance to cut anything is pretty damn good.
> Unless you're just flat-out careless or stupid (or both) and are wildly
> advancing your fingers towards the blade, 17 teeth are not going to do
> much damage. I could do much worse in the blink of an eye with a
> careless swipe of my pocketknife.
>
I've seen a hotdog demonstration in which they *did* push the dog, on
top of a piece of wood, into the blade as quick as the blade with
receive it. It was much faster than anyone with any sense would advance
any stock into a table saw. The dog had the tiniest little sliver of
"skin" taken off. Had it been a finger, it would surely have bled a drop
or two. But I've done much worse to my finger when a file slipped or I
got a splinter.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/12/10 12:13 PM, Josepi wrote:
> This was exactly my point.
>
> The other thing, and unfair to the 17 teeth is OK defence is that the
> SawStop pulls the blade away and down. It appears to be grabbed on the back
> side of the blade and the inertia pulls the balde back and under the table
> effectively removing the blade from the finger area. I doubt you would want
> to do this everytime in a **NON**emergency stop. My guess is arbor bending
> would set in after a few dozen of them.
>
> Watch the videos (most have). This is no gentle stop for an armature and saw
> blade of that intertia.
>
> So the retort to the 17 teeth big damage people is still "How fast do you
> push your finger?"
>
> OTOH: Pushing the stock, slipping off, and back handing a running blade can
> be different speeds.
>
I guess I don't know what we're debating, anymore.
I thought we were talking about slowing down the coast of a saw blade
after turning off the power. I guess we got on a tangent.
If it's you're mission to dream up ways to refute the effectiveness of
the SawStop technology... well, I'm off the boat, because you've lost
your mind. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/12/10 9:12 PM, Hoosierpopi wrote:
> On Oct 10, 10:27 pm, -MIKE-<[email protected]> wrote:
>
> "electromagnet/solenoid would do the trick"
>
> My God man, you've invented the Saw Stop!
>
Hardly.
There's a lot more more going on with that thing than a simple current
running through a magnet.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/12/2010 9:19 PM, Hoosierpopi wrote:
> On Oct 12, 12:21 pm, Steve Turner<[email protected]>
> wrote:
>
> wildly advancing your fingers towards the blade,
>
> As is done when, say, you are pushing a bit of wood into the saw and
> it jerks out of place and you essentially "fall" forward now that the
> wood is no longer offering resistance?
I've read that about five times and have tried to visualize what you're talking
about, but I'm still puzzled.
> Of course, the blade never stop turning at all on the saw I was using,
> but I did manage to put three finges and a thumb in its path before
> realizing I was cutting skin and bone - and jerked back.
>
> Only cut clean through one digit and got it sewed and screwed back
> on.
Would I be correct in assuming you were pushing the wood into the blade with
your bare hands rather than using a push jig or Gripper or something similar?
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
J. Clarke wrote:
> In article<[email protected]>,
> [email protected] says...
>>
>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>
>>> J. Clarke wrote:
>>>> In article<[email protected]>, [email protected] says...
>>>>>
>>>>> I would think that an emergency stop mechanism would be a whole different
>>>>> magnitude than a scheduled, everyday, stop.
>>>>>
>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>>>>> would be OK too. These two situations would require different tactics.
>>>>>
>>>>> A dynamic electronic brake could vary the intensity for the two different
>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
>>>>> replaced frequently.
>>>>
>>>> So how much power do you have to put into that electronic brake to stop
>>>> the blade as fast as Sawstop's physical block?
>>>>
>>>> And why would a caliper not last long? A set of brake pads on a car
>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>>>> a lot more of a workout that they would stopping a little bitty saw
>>>> blade that masses less than 1/1000 as much.
>>>
>>> The physics on that seem interesting. A little like stopping a speeding
>>> bullet on a dime--it challenges my imagination. Probably not quite as
>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
>>> either.
>>>
>>> Bill
>> No way a caliper could stop the blade in even 4X the time the
>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> the blade would be quite problematic - with dust decreasing the
>> stopping efficiency by a very large margin.
>
> I suspect that a small pyrotechnic pressurizing one of the calipers off
> my '76 Lincoln might surprise you.
>
When it snapped (seriously)? I'm not an engineer, so I don't know for
sure. I just wouldn't be surprised. Maybe someone else can opine.
Bill
On Thu, 14 Oct 2010 11:44:16 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 11:17 AM, Bill wrote:
>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>> Another reality check for all the people taking this thread off into the
>>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>>> presence of calipers that grip either side of the blade. My interest
>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>> matter of "how can I retrofit my existing table saw with a simple
>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>> calipers to drop out of the way) would allow enough clearance to get the
>>>> blade on the arbor without too much trouble.
>>>
>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>> pad on the arbor side of the blade would be sufficient for a convenience
>>> slow/stop.
>>
>> Maybe so, but that sounds like asking for trouble!
>>
>> Bill
>
>How? Really. :-)
You NEVER put side loads on a saw blade , particularly when running
at speed.
[email protected] wrote:
> On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> Scott Lurndal wrote:
>>
>>>
>>> On the other hand, disc brakes are designed so they don't lock up,
>>> this includes the materials used as well plus the modern ABS
>>> electronics.
>>>
>>
>> No they aren't. ABS systems are designed to prevent the wheel from
>> locking up, but disk brakes aren't. In fact, quite the opposite,
>> they are designed to lock up but rely upon the ABS to govern them so
>> they don't.
> Not true. Drum brakes are much more powerfull on the first
> application, and more likely to lock up due to their self-energizing
> servo action (virtually every drum brake on a vehicle in the last 40
> years) The only advantage of disks is faster cooling and less fade.
You are incorrect sir. What I stated is very correct. Disk brakes are not
designed so that they will not lock up. In fact - they will lock up.
Pointing out any difference in the lock up characteristic between disk and
rotor does nothing to argue that point. All that says is that there is a
difference, not that disks will not lock up. Anyone who says that disk
brakes will not lock up has no familiarity with disk brakes. I agree with
your statement that the advantage to disks is that they fade less due to
better cooling, but that very statement in itself, a contradiction to your
very assertion.
--
-Mike-
[email protected]
On 10/14/10 2:24 PM, [email protected] wrote:
>>
>> How? Really. :-)
> You NEVER put side loads on a saw blade , particularly when running
> at speed.
1. It wouldn't be running.
2. What I'm talking about could hardly be considered a load.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
<[email protected]> wrote:
>Scott Lurndal wrote:
>
>>
>> On the other hand, disc brakes are designed so they don't lock up,
>> this includes the materials used as well plus the modern ABS
>> electronics.
>>
>
>No they aren't. ABS systems are designed to prevent the wheel from locking
>up, but disk brakes aren't. In fact, quite the opposite, they are designed
>to lock up but rely upon the ABS to govern them so they don't.
Not true. Drum brakes are much more powerfull on the first
application, and more likely to lock up due to their self-energizing
servo action (virtually every drum brake on a vehicle in the last 40
years) The only advantage of disks is faster cooling and less fade.
J. Clarke wrote:
> In article<[email protected]>, [email protected] says...
>>
>> J. Clarke wrote:
>>> In article<[email protected]>,
>>> [email protected] says...
>>>>
>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>
>>>>> J. Clarke wrote:
>>>>>> In article<[email protected]>, [email protected] says...
>>>>>>>
>>>>>>> I would think that an emergency stop mechanism would be a whole different
>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>
>>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>>>>>>> would be OK too. These two situations would require different tactics.
>>>>>>>
>>>>>>> A dynamic electronic brake could vary the intensity for the two different
>>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
>>>>>>> replaced frequently.
>>>>>>
>>>>>> So how much power do you have to put into that electronic brake to stop
>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>
>>>>>> And why would a caliper not last long? A set of brake pads on a car
>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>>>>>> a lot more of a workout that they would stopping a little bitty saw
>>>>>> blade that masses less than 1/1000 as much.
>>>>>
>>>>> The physics on that seem interesting. A little like stopping a speeding
>>>>> bullet on a dime--it challenges my imagination. Probably not quite as
>>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
>>>>> either.
>>>>>
>>>>> Bill
>>>> No way a caliper could stop the blade in even 4X the time the
>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>>>> the blade would be quite problematic - with dust decreasing the
>>>> stopping efficiency by a very large margin.
>>>
>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>> my '76 Lincoln might surprise you.
>>>
>>
>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>
> Why would something that can stop a 4000 pound car "snap" when called on
> to stop a 3 pound saw blade?
"Pyrotechnics" rather than a master cylinder with brake fluid?
Bill
On Fri, 15 Oct 2010 13:13:27 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> Scott Lurndal wrote:
>>>
>>>>
>>>> On the other hand, disc brakes are designed so they don't lock up,
>>>> this includes the materials used as well plus the modern ABS
>>>> electronics.
>>>>
>>>
>>> No they aren't. ABS systems are designed to prevent the wheel from
>>> locking up, but disk brakes aren't. In fact, quite the opposite,
>>> they are designed to lock up but rely upon the ABS to govern them so
>>> they don't.
>> Not true. Drum brakes are much more powerfull on the first
>> application, and more likely to lock up due to their self-energizing
>> servo action (virtually every drum brake on a vehicle in the last 40
>> years) The only advantage of disks is faster cooling and less fade.
>
>You are incorrect sir. What I stated is very correct. Disk brakes are not
>designed so that they will not lock up. In fact - they will lock up.
>Pointing out any difference in the lock up characteristic between disk and
>rotor does nothing to argue that point. All that says is that there is a
>difference, not that disks will not lock up. Anyone who says that disk
>brakes will not lock up has no familiarity with disk brakes. I agree with
>your statement that the advantage to disks is that they fade less due to
>better cooling, but that very statement in itself, a contradiction to your
>very assertion.
Pardon? What are you dissagreeing with?? Did I say disk brakes won't
lock up? NO
And there is NO contadiction to my statement. On first application, a
drum brake will ALWAYS outperform a disk on first application. Many
times also on second application. Disk brakes only outstop drum brakes
when both are hot.
Disk brakes are not "designed to lock up" They are designed that you
CAN (in many, but not all cases) lock the wheels on clean dry pavement
with hard brake application. You CAN lock the brakes in poor traction
conditions, but the locking capability is only due to their stopping
power being excessive foe some conditions. They are, by design, LESS
likely to lock than a Bendix type self energizing drum brake.
On Fri, 15 Oct 2010 09:49:34 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>, [email protected] says...
>>
>> Disc brake were around for a lot longer than the ABS systems were ever
>> implemented.
>> Disc brakes were not sdesigned to "lock up" but rather be more linear than
>> shoe brake systems, and fade less.
>>
>> "Mike Marlow" <[email protected]> wrote in message
>> news:[email protected]...
>> No they aren't. ABS systems are designed to prevent the wheel from locking
>> up, but disk brakes aren't. In fact, quite the opposite, they are designed
>> to lock up but rely upon the ABS to govern them so they don't.
>
>They're not "designed to lock up", they're designed as a compromise
>between maximum braking force, fade, pad wear, weight, and cost. Most
>disk brakes can be locked.
>
>ABS is intended to save your ass when there's poor traction by
>preventing lock--it will also prevent lock on good surfaces but
>generally isn't needed for that purpose.
>
>> Scott Lurndal wrote:
>> > On the other hand, disc brakes are designed so they don't lock up,
>> > this includes the materials used as well plus the modern ABS
>> > electronics.
>> >
>
I've had more "success" locking drum brakes on dry pavement than
disks. For CAFE reasons they put the lightest disk brake assembly they
can get away with on most vehicles.
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 09:49:34 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>, [email protected] says...
> >>
> >> Disc brake were around for a lot longer than the ABS systems were ever
> >> implemented.
> >> Disc brakes were not sdesigned to "lock up" but rather be more linear than
> >> shoe brake systems, and fade less.
> >>
> >> "Mike Marlow" <[email protected]> wrote in message
> >> news:[email protected]...
> >> No they aren't. ABS systems are designed to prevent the wheel from locking
> >> up, but disk brakes aren't. In fact, quite the opposite, they are designed
> >> to lock up but rely upon the ABS to govern them so they don't.
> >
> >They're not "designed to lock up", they're designed as a compromise
> >between maximum braking force, fade, pad wear, weight, and cost. Most
> >disk brakes can be locked.
> >
> >ABS is intended to save your ass when there's poor traction by
> >preventing lock--it will also prevent lock on good surfaces but
> >generally isn't needed for that purpose.
> >
> >> Scott Lurndal wrote:
> >> > On the other hand, disc brakes are designed so they don't lock up,
> >> > this includes the materials used as well plus the modern ABS
> >> > electronics.
> >> >
> >
> I've had more "success" locking drum brakes on dry pavement than
> disks. For CAFE reasons they put the lightest disk brake assembly they
> can get away with on most vehicles.
I don't see locking brakes as "success" but I can if I want to lock up
my Grand Cherokee on a dry road.
And we were talking about a caliper from a '76 Lincoln, which has
absolutely _nothing_ "light" on it.
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
> >Josepi wrote:
> >
> >> Disc brake were around for a lot longer than the ABS systems were ever
> >> implemented.
> >> Disc brakes were not sdesigned to "lock up" but rather be more linear
> >> than shoe brake systems, and fade less.
> >>
> >
> >You are correct that disk brakes have been around a lot longer than ABS has,
> >but if you believe that disk brakes will not lock up then you simply need to
> >drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
> >Why do you think ABS exists?
> Because most drivers don't (according to our governments and highway
> safety people) have the brains to release their brakes when the wheels
> start to slide.
The best driver in the world can't sense lock and modulate the pedal as
quickly or consistently as a computer with a sensor on each wheel.
On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 2:24 PM, [email protected] wrote:
>>>
>>> How? Really. :-)
>> You NEVER put side loads on a saw blade , particularly when running
>> at speed.
>
>1. It wouldn't be running.
>2. What I'm talking about could hardly be considered a load.
Mike, typical caliper pads are unloaded by the play in the wheel
bearings and a bit of runout on the disc. Unless you have some wobble
in the blade, the pads will continue to drag on the blade. Just one
more thing to work out. Build self-retracting pad retractors and...
You'll be rich!
--
Do not taunt Happy Fun Ball!
[email protected] wrote:
> On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>>
>>
>> You are correct that disk brakes have been around a lot longer than
>> ABS has, but if you believe that disk brakes will not lock up then
>> you simply need to drive a car that pre-dates ABS. Disk brakes will
>> most certainly lock up. Why do you think ABS exists?
> Because most drivers don't (according to our governments and highway
> safety people) have the brains to release their brakes when the wheels
> start to slide.
Well come on now and at least try to be fair. How could you expect today's
drivers to focus on both braking technique and texting at the same time, and
do either well? I think some study by some leading university has shown
that pumping brakes while texting results in missed letters in messages.
Can't have that now...
--
-Mike-
[email protected]
On Oct 17, 9:01=A0am, [email protected] (Doug Miller) wrote:
.
>
> Another major advantage of discs over drums is that they still work -- fi=
rst
> time -- after driving through a puddle, because the water can drain away.
Unless the puddle has some oak rust floating in it...in that case we
are all doomed.
On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
<[email protected]> wrote:
>Josepi wrote:
>
>> Disc brake were around for a lot longer than the ABS systems were ever
>> implemented.
>> Disc brakes were not sdesigned to "lock up" but rather be more linear
>> than shoe brake systems, and fade less.
>>
>
>You are correct that disk brakes have been around a lot longer than ABS has,
>but if you believe that disk brakes will not lock up then you simply need to
>drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
>Why do you think ABS exists?
Because most drivers don't (according to our governments and highway
safety people) have the brains to release their brakes when the wheels
start to slide.
On 10/16/10 6:47 PM, Larry Jaques wrote:
> On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE-<[email protected]>
> wrote:
>
>> On 10/14/10 2:24 PM, [email protected] wrote:
>>>>
>>>> How? Really. :-)
>>> You NEVER put side loads on a saw blade , particularly when running
>>> at speed.
>>
>> 1. It wouldn't be running.
>> 2. What I'm talking about could hardly be considered a load.
>
> Mike, typical caliper pads are unloaded by the play in the wheel
> bearings and a bit of runout on the disc.
Please note that I never bought in to the caliper thing, before you
include me in an argument I've opted out of. :-)
I am still talking about a bicycle style spring and/or solenoid/magnetic
brake.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, [email protected] wrote:
>It has been proven over and over. They have, generally, more than
>twice the friction area of a disk brake of the same diameter, and
>being self energizing require much less pedal effort. Drum brakes do
>not REQUIRE power boosters, while disk brakes, generally, are pittiful
>without them. I'll put a 10 1/2 X2 1/2 drum brake up against an 11
>inch disk any day of the week for a cold stop. and beat it hands down.
Complete and utter nonsense. It's evident that you've never driven a car with
unassisted disc brakes. I owned one for three years (Fiat X-1/9), and I can
attest that the disc brakes in that car were *far* more effective than the
drum brakes, assisted or not, in any other vehicle I've ever driven.
>After 2 60mph stops within about 1 1/2 - 2 minutes the disk brake will
>start gaining. By the third stop within 2 minutes it will be
>outstopping the drum brake on a good day.
Disc brakes outstop drum brakes, on good days or bad, beginning with the first
stop.
Another major advantage of discs over drums is that they still work -- first
time -- after driving through a puddle, because the water can drain away.
On Fri, 15 Oct 2010 09:49:34 -0400, "J. Clarke"
<[email protected]> wrote:
>ABS is intended to save your ass when there's poor traction by
>preventing lock--it will also prevent lock on good surfaces but
>generally isn't needed for that purpose.
Especially important in the first commercial application of ABS.
Mark
On Thu, 14 Oct 2010 13:00:44 -0500, -MIKE- <[email protected]> wrote:
>On 10/14/10 12:58 PM, Robatoy wrote:
>> Any disc or drum of any size will interfere with the raising of the
>> blade to the point that the disk brake hits the bottom of the table
>> somewhere.
>>
>> I propose an air bag. Electronically triggered, it throws you
>> backwards across the shop and away from the table saw. Punches you
>> right in the chest with the option for a double bag for some people
>> here in which case the second bag knocks some sense in them. We can
>> glue on a boxing glove for that operation...just a 4 oz. one; you want
>> it to hurt a little.
>> One can mount the boxing glove on an expanding multi-pivot articulated
>> parallelogram.
>> What a stellar idea.
>> I'm talking to investors now.
>> They want to call the company ACME.
>
>Beautiful. Wile E. fricken beautiful.
Coyote ugly.
Geeeeee. Ask a mechanic about brakes. What a concept...LOL
<[email protected]> wrote in message
news:[email protected]...
And there is NO contadiction to my statement. On first application, a
drum brake will ALWAYS outperform a disk on first application. Many
times also on second application. Disk brakes only outstop drum brakes
when both are hot.
Disk brakes are not "designed to lock up" They are designed that you
CAN (in many, but not all cases) lock the wheels on clean dry pavement
with hard brake application. You CAN lock the brakes in poor traction
conditions, but the locking capability is only due to their stopping
power being excessive foe some conditions. They are, by design, LESS
likely to lock than a Bendix type self energizing drum brake.
On Fri, 15 Oct 2010 11:54:46 -0400, [email protected] wrote:
>On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
><[email protected]> wrote:
>
>>Scott Lurndal wrote:
>>
>>>
>>> On the other hand, disc brakes are designed so they don't lock up,
>>> this includes the materials used as well plus the modern ABS
>>> electronics.
>>>
>>
>>No they aren't. ABS systems are designed to prevent the wheel from locking
>>up, but disk brakes aren't. In fact, quite the opposite, they are designed
>>to lock up but rely upon the ABS to govern them so they don't.
> Not true. Drum brakes are much more powerfull on the first
>application,
False.
>and more likely to lock up due to their self-energizing
>servo action (virtually every drum brake on a vehicle in the last 40
>years)
True.
>The only advantage of disks is faster cooling and less fade.
The main advantage is efficiency. For a given poundage and square inch
of pad, they're better than drums. Ask any Viper/Carerra/Corvette
driver or motorcycle rider if they want to regress to drums. You'll
be run out of town on a rail.
One article.
http://www.edmunds.com/ownership/techcenter/articles/43857/article.html
LJ --"retired" mechanic whose Tundra (4-wheel disc brakes) will stop
on a dime...and give change.
--
Do not taunt Happy Fun Ball!
On Mon, 18 Oct 2010 12:27:39 -0500, -MIKE- <[email protected]>
wrote:
>On 10/18/10 12:23 PM, [email protected] wrote:
>> And you are WRONG again, Robotoy.
>> Disc brakes were invented before flight.
>>
>> The drum brake, as it is now known, became all-dominant in the United
>> States. In Europe, particularly in Great Britain, it had to share the
>> stage with disc brakes. Disc brakes became more or less standard on
>> European cars during the '50s, about 20 years before they were adopted
>> by American manufacturers in 1973.
>>
>> This is ironic, because the spot-type disc brake is an American
>> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
>> electric car having front-wheel disc brakes.
>>
>> He made a large disc integral with the hub on each wheel.
>> Electromagnets were used to press smaller discs, lined with a friction
>> material, against spots on the rotating disc to bring the wheel to a
>> stop. Springs retracted the spot discs when current was interrupted.
>>
>> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
>> Lanchester for a nonelectric spot disc braking system that's similar
>> in principle to what we have today. The biggest problem that
>> Lanchester encountered was noise. Metal-to-metal contact between his
>> copper linings and the metal disc caused an intense screech that sent
>> chills through anyone within earshot.
>>
>> The problem was solved in 1907 when Herbert Frood, another Englishman,
>> came up with the idea of lining pads with asbestos. The new material
>> was quickly adopted by car manufacturers on both drum and disc brakes.
>> Asbestos linings also outlasted other friction materials by a wide
>> margin. The 10,000-mile brake job had arrived.
>>
>> As roads improved and cars began to be driven at high speeds,
>> manufacturers recognized the need for even greater braking power. One
>> solution to the problem became apparent during the Elgin road Race of
>> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
>> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
>> such magnificent braking power was to simply use an internal brake on
>> each front wheel as well as each rear wheel.
>>
>> In 1918, a young inventor named Malcolm Lougheed (who later changed
>> the spelling of his name to Lockheed) applied hydraulics to braking.
>> He used cylinders and tubes to transmit fluid pressure against brake
>> shoes, pushing the shoes against the drums. In 1921, the first
>> passenger car to be equipped with four-wheel hydraulic brakes appeared
>> -- the Model A Duesenberg.
>>
>> Carmakers as a group were not quick to adopt hydraulics. Ten years
>> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
>> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
>> the others still had cable-operated mechanical brakes. In fact, it was
>> not until 1939 that Ford finally gave in, becoming the last major
>> manufacturer to switch to hydraulic brakes.
>>
>> The basic braking system we have today was pretty much in place by
>> 1921, including a refinement some regard as contemporary -- power
>> assist.
>>
>> Power assist, technically, dates back to 1903 when a car called the
>> Tincher used air brakes. But the first car to be equipped with a
>> vacuum-operated power booster similar to those we have today was the
>> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
>> the physical effort needed to apply brakes. Vacuum boosters from then
>> to now have similar designs.
>>
>> The first widespread deviation from vacuum power assist came about in
>> 1985. Some '85 GM cars use an electrically driven brake booster, which
>> is smaller and lighter than the conventional vacuum booster, giving an
>> all-hydraulic system. Some cars with antilock brakes also use
>> all-hydraulic systems.
>>
>> The first car to have self-adjusting brakes was the 1925 Cole. The
>> prototype for today's systems appeared on the 1946 Studebaker. The
>> mechanism by Wagner Electric Co., consisted of an adjusting wedge
>> under the influence of a tension spring. As linings wore, a plug
>> receded to move a pin and lever against the spring. This forced the
>> adjusting wedge against brake shoes, which expanded to keep linings at
>> a preset distance from the drums.
>>
>> As for the antilock (antiskid) units now available in the U.S., they
>> are hardly new. The first practical antiskid braking system, named
>> Maxaret, was developed in 1958 by the Road Research Laboratories in
>> Great Britain and was first applied to the Jensen FF sports sedan in
>> 1966.
>>
>> Three years later, in 1969, the Lincoln Continental Mark III was
>> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
>> Sensors on the rear wheels transmitted signals to a transistorized
>> "computer" behind the glove box. The computer controlled a
>> vacuum-operated valve on the rear brake line to modulate pressure to
>> the rear brakes when the sensors told the computer that the brakes
>> were locking.
>>
>> Cost and some technical problems caused the shelving of this unit. But
>> now, updated versions that give four-wheel skid control are offered on
>> almost every car model, although initially they were available only on
>> high-end cars like Lincoln and Mercedes, and a few European cars.
>>
>> Computerized brakes notwithstanding, there is a piece of advice about
>> using brakes that's as relevant today as it was in 1909 when it was
>> first published in The American Cyclopedia of the Automobile:
>>
>> "Good driving in traffic is shown by making the minimum use of brakes.
>> The strain on passengers amounts to intense nervousness when the car
>> is constantly driven so that the least alteration of direction or of
>> pace on the part of any vehicle ahead results in the violent
>> application of the brake."
>>
>> And so it will always be.
>>
>
>Are you going to at least give credit to the websites from which you
>cut-n-pasted all this?
Sorry - I believe it was originally published on the internet by
motorera.com
Not sure where it came from before that, as I have seen it in several
different places.
On 10/18/10 1:04 PM, [email protected] wrote:
> On Mon, 18 Oct 2010 12:27:39 -0500, -MIKE-<[email protected]>
> wrote:
>>> Are you going to at least give credit to the websites from which you
>> cut-n-pasted all this?
> Sorry - I believe it was originally published on the internet by
> motorera.com
> Not sure where it came from before that, as I have seen it in several
> different places.
Riiiiiiight. You're saying you typed it out, verbatim, from memory
Rainman? :-p
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Sat, 16 Oct 2010 17:03:40 -0700, Larry Jaques
<[email protected]> wrote:
>On Fri, 15 Oct 2010 11:54:46 -0400, [email protected] wrote:
>
>>On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
>><[email protected]> wrote:
>>
>>>Scott Lurndal wrote:
>>>
>>>>
>>>> On the other hand, disc brakes are designed so they don't lock up,
>>>> this includes the materials used as well plus the modern ABS
>>>> electronics.
>>>>
>>>
>>>No they aren't. ABS systems are designed to prevent the wheel from locking
>>>up, but disk brakes aren't. In fact, quite the opposite, they are designed
>>>to lock up but rely upon the ABS to govern them so they don't.
>> Not true. Drum brakes are much more powerfull on the first
>>application,
>
>False.
It has been proven over and over. They have, generally, more than
twice the friction area of a disk brake of the same diameter, and
being self energizing require much less pedal effort. Drum brakes do
not REQUIRE power boosters, while disk brakes, generally, are pittiful
without them. I'll put a 10 1/2 X2 1/2 drum brake up against an 11
inch disk any day of the week for a cold stop. and beat it hands down.
After 2 60mph stops within about 1 1/2 - 2 minutes the disk brake will
start gaining. By the third stop within 2 minutes it will be
outstopping the drum brake on a good day.
3 hard stops in a row will make the disks shine (and mabee even glow)
>
>
>>and more likely to lock up due to their self-energizing
>>servo action (virtually every drum brake on a vehicle in the last 40
>>years)
>
>True.
>
>
>>The only advantage of disks is faster cooling and less fade.
>
>The main advantage is efficiency. For a given poundage and square inch
>of pad, they're better than drums.
NOT when cold. Most disk brakes are actually pretty inneffective
before they get warmed up and they definitely require higher hydraulic
pressure to work, period.
> Ask any Viper/Carerra/Corvette
>driver or motorcycle rider if they want to regress to drums. You'll
>be run out of town on a rail.
like I said - the drum will outstop the disk for the FIRST STOP.
Unless that stop is from 100mph or with an overloaded vehicle.
Second stop is anyone's guess - depending on the severity of the stop.
>
>One article.
>http://www.edmunds.com/ownership/techcenter/articles/43857/article.html
>
>
>LJ --"retired" mechanic whose Tundra (4-wheel disc brakes) will stop
>on a dime...and give change.
On Mon, 18 Oct 2010 13:34:38 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 18, 1:23Â pm, [email protected] wrote:
>> On Sun, 17 Oct 2010 22:59:03 -0400, [email protected] wrote:
>> >On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
>> >wrote:
>>
>> >>Rust on the back disks from lack of heavy usage.
>>
>> >>I doubt it would be oak rust, though.
>>
>> >>"Robatoy" <[email protected]> wrote in message
>> >>news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com...
>> >>All you need to do is look at the history of the disc brake.
>> >>Lightweight, high-speed stopping power, reliable, operable in wet
>> >>conditions... IOW...aircraft.
>>
>> Â And you are WRONG again, Robotoy.
>> Disc brakes were invented before flight.
>>
>> The drum brake, as it is now known, became all-dominant in the United
>> States. In Europe, particularly in Great Britain, it had to share the
>> stage with disc brakes. Disc brakes became more or less standard on
>> European cars during the '50s, about 20 years before they were adopted
>> by American manufacturers in 1973.
>>
>> This is ironic, because the spot-type disc brake is an American
>> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
>> electric car having front-wheel disc brakes.
>>
>> He made a large disc integral with the hub on each wheel.
>> Electromagnets were used to press smaller discs, lined with a friction
>> material, against spots on the rotating disc to bring the wheel to a
>> stop. Springs retracted the spot discs when current was interrupted.
>>
>> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
>> Lanchester for a nonelectric spot disc braking system that's similar
>> in principle to what we have today. The biggest problem that
>> Lanchester encountered was noise. Metal-to-metal contact between his
>> copper linings and the metal disc caused an intense screech that sent
>> chills through anyone within earshot.
>>
>> The problem was solved in 1907 when Herbert Frood, another Englishman,
>> came up with the idea of lining pads with asbestos. The new material
>> was quickly adopted by car manufacturers on both drum and disc brakes.
>> Asbestos linings also outlasted other friction materials by a wide
>> margin. The 10,000-mile brake job had arrived.
>>
>> As roads improved and cars began to be driven at high speeds,
>> manufacturers recognized the need for even greater braking power. One
>> solution to the problem became apparent during the Elgin road Race of
>> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
>> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
>> such magnificent braking power was to simply use an internal brake on
>> each front wheel as well as each rear wheel.
>>
>> In 1918, a young inventor named Malcolm Lougheed (who later changed
>> the spelling of his name to Lockheed) applied hydraulics to braking.
>> He used cylinders and tubes to transmit fluid pressure against brake
>> shoes, pushing the shoes against the drums. In 1921, the first
>> passenger car to be equipped with four-wheel hydraulic brakes appeared
>> -- the Model A Duesenberg.
>>
>> Carmakers as a group were not quick to adopt hydraulics. Ten years
>> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
>> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
>> the others still had cable-operated mechanical brakes. In fact, it was
>> not until 1939 that Ford finally gave in, becoming the last major
>> manufacturer to switch to hydraulic brakes.
>>
>> The basic braking system we have today was pretty much in place by
>> 1921, including a refinement some regard as contemporary -- power
>> assist.
>>
>> Power assist, technically, dates back to 1903 when a car called the
>> Tincher used air brakes. But the first car to be equipped with a
>> vacuum-operated power booster similar to those we have today was the
>> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
>> the physical effort needed to apply brakes. Vacuum boosters from then
>> to now have similar designs.
>>
>> The first widespread deviation from vacuum power assist came about in
>> 1985. Some '85 GM cars use an electrically driven brake booster, which
>> is smaller and lighter than the conventional vacuum booster, giving an
>> all-hydraulic system. Some cars with antilock brakes also use
>> all-hydraulic systems.
>>
>> The first car to have self-adjusting brakes was the 1925 Cole. The
>> prototype for today's systems appeared on the 1946 Studebaker. The
>> mechanism by Wagner Electric Co., consisted of an adjusting wedge
>> under the influence of a tension spring. As linings wore, a plug
>> receded to move a pin and lever against the spring. This forced the
>> adjusting wedge against brake shoes, which expanded to keep linings at
>> a preset distance from the drums.
>>
>> As for the antilock (antiskid) units now available in the U.S., they
>> are hardly new. The first practical antiskid braking system, named
>> Maxaret, was developed in 1958 by the Road Research Laboratories in
>> Great Britain and was first applied to the Jensen FF sports sedan in
>> 1966.
>>
>> Three years later, in 1969, the Lincoln Continental Mark III was
>> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
>> Sensors on the rear wheels transmitted signals to a transistorized
>> "computer" behind the glove box. The computer controlled a
>> vacuum-operated valve on the rear brake line to modulate pressure to
>> the rear brakes when the sensors told the computer that the brakes
>> were locking.
>>
>> Cost and some technical problems caused the shelving of this unit. But
>> now, updated versions that give four-wheel skid control are offered on
>> almost every car model, although initially they were available only on
>> high-end cars like Lincoln and Mercedes, and a few European cars.
>>
>> Computerized brakes notwithstanding, there is a piece of advice about
>> using brakes that's as relevant today as it was in 1909 when it was
>> first published in The American Cyclopedia of the Automobile:
>>
>> "Good driving in traffic is shown by making the minimum use of brakes.
>> The strain on passengers amounts to intense nervousness when the car
>> is constantly driven so that the least alteration of direction or of
>> pace on the part of any vehicle ahead results in the violent
>> application of the brake."
>>
>> And so it will always be.
>>
>>
>>
>> >>On the back-end of a competition car, inboard disc brakes are often
>> >>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
>> >>competition drive systems, the discs are sometimes even found inboard,
>> >>at the front-end.
>>
>> >>There simply isn't one single reason NOT to have disc brakes.
>>
>> > There were even a few inboard DRUM brake vehicles built. Front drive
>> >too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??
>
>How does that make me wrong? Are you telling me that disc brakes are
>not the preferred system for aircraft for all those reasons I laid
>out? That it wasn't the aircraft people who developed many facets of
>those systems?
You stated, or appeared to state, that disc brakes were developed for
aircraft use and they were lighter because of that.
In that, you are wrong. If that's not what you MEANT, it IS what you
SAID.
>Tell you what..... there was a guy in my home-town in Holland who tied
>his 1930-sh Somethingmobile to a tree with a rope so it wouldn't roll
>down his laneway. Now I suppose you will give me a dissertation on
>rope-brake systems through the frikkin' ages as well? What about
>parachute brakes? There are all kinds of people using those. The
>Veyron uses a big paddle that rises out of the back of the car to
>assist slowing the thing down.
>Anywhooo.. disc brakes are the preferred systems regardless whether or
>not the Queen's carriage has a leather pad rubbing on the tyres.
And I never said disc brakes were not better, overall than drums.
All I said, which you have not been able to, and never will be able to
prove me wrong, is that a drum brake, properly set up and adjusted,
will stop a car more effectively on the first stop than a disc of the
same size on the same car. It is a proven fact.
It is also a proven fact that a properly designed and implemented disc
brake will outbrake any drum brake under extreme use and in repeated
applications. I have never disputed that.
On Oct 18, 10:58=A0pm, [email protected] wrote:
> On Mon, 18 Oct 2010 13:34:38 -0700 (PDT), Robatoy
>
>
>
>
>
> <[email protected]> wrote:
> >On Oct 18, 1:23=A0pm, [email protected] wrote:
> >> On Sun, 17 Oct 2010 22:59:03 -0400, [email protected] wrote:
> >> >On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
> >> >wrote:
>
> >> >>Rust on the back disks from lack of heavy usage.
>
> >> >>I doubt it would be oak rust, though.
>
> >> >>"Robatoy" <[email protected]> wrote in message
> >> >>news:[email protected]=
om...
> >> >>All you need to do is look at the history of the disc brake.
> >> >>Lightweight, high-speed stopping power, reliable, operable in wet
> >> >>conditions... IOW...aircraft.
>
> >> =A0And you are WRONG again, Robotoy.
> >> Disc brakes were invented before flight.
>
> >> The drum brake, as it is now known, became all-dominant in the United
> >> States. In Europe, particularly in Great Britain, it had to share the
> >> stage with disc brakes. Disc brakes became more or less standard on
> >> European cars during the '50s, about 20 years before they were adopted
> >> by American manufacturers in 1973.
>
> >> This is ironic, because the spot-type disc brake is an American
> >> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
> >> electric car having front-wheel disc brakes.
>
> >> He made a large disc integral with the hub on each wheel.
> >> Electromagnets were used to press smaller discs, lined with a friction
> >> material, against spots on the rotating disc to bring the wheel to a
> >> stop. Springs retracted the spot discs when current was interrupted.
>
> >> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
> >> Lanchester for a nonelectric spot disc braking system that's similar
> >> in principle to what we have today. The biggest problem that
> >> Lanchester encountered was noise. Metal-to-metal contact between his
> >> copper linings and the metal disc caused an intense screech that sent
> >> chills through anyone within earshot.
>
> >> The problem was solved in 1907 when Herbert Frood, another Englishman,
> >> came up with the idea of lining pads with asbestos. The new material
> >> was quickly adopted by car manufacturers on both drum and disc brakes.
> >> Asbestos linings also outlasted other friction materials by a wide
> >> margin. The 10,000-mile brake job had arrived.
>
> >> As roads improved and cars began to be driven at high speeds,
> >> manufacturers recognized the need for even greater braking power. One
> >> solution to the problem became apparent during the Elgin road Race of
> >> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
> >> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
> >> such magnificent braking power was to simply use an internal brake on
> >> each front wheel as well as each rear wheel.
>
> >> In 1918, a young inventor named Malcolm Lougheed (who later changed
> >> the spelling of his name to Lockheed) applied hydraulics to braking.
> >> He used cylinders and tubes to transmit fluid pressure against brake
> >> shoes, pushing the shoes against the drums. In 1921, the first
> >> passenger car to be equipped with four-wheel hydraulic brakes appeared
> >> -- the Model A Duesenberg.
>
> >> Carmakers as a group were not quick to adopt hydraulics. Ten years
> >> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
> >> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
> >> the others still had cable-operated mechanical brakes. In fact, it was
> >> not until 1939 that Ford finally gave in, becoming the last major
> >> manufacturer to switch to hydraulic brakes.
>
> >> The basic braking system we have today was pretty much in place by
> >> 1921, including a refinement some regard as contemporary -- power
> >> assist.
>
> >> Power assist, technically, dates back to 1903 when a car called the
> >> Tincher used air brakes. But the first car to be equipped with a
> >> vacuum-operated power booster similar to those we have today was the
> >> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
> >> the physical effort needed to apply brakes. Vacuum boosters from then
> >> to now have similar designs.
>
> >> The first widespread deviation from vacuum power assist came about in
> >> 1985. Some '85 GM cars use an electrically driven brake booster, which
> >> is smaller and lighter than the conventional vacuum booster, giving an
> >> all-hydraulic system. Some cars with antilock brakes also use
> >> all-hydraulic systems.
>
> >> The first car to have self-adjusting brakes was the 1925 Cole. The
> >> prototype for today's systems appeared on the 1946 Studebaker. The
> >> mechanism by Wagner Electric Co., consisted of an adjusting wedge
> >> under the influence of a tension spring. As linings wore, a plug
> >> receded to move a pin and lever against the spring. This forced the
> >> adjusting wedge against brake shoes, which expanded to keep linings at
> >> a preset distance from the drums.
>
> >> As for the antilock (antiskid) units now available in the U.S., they
> >> are hardly new. The first practical antiskid braking system, named
> >> Maxaret, was developed in 1958 by the Road Research Laboratories in
> >> Great Britain and was first applied to the Jensen FF sports sedan in
> >> 1966.
>
> >> Three years later, in 1969, the Lincoln Continental Mark III was
> >> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
> >> Sensors on the rear wheels transmitted signals to a transistorized
> >> "computer" behind the glove box. The computer controlled a
> >> vacuum-operated valve on the rear brake line to modulate pressure to
> >> the rear brakes when the sensors told the computer that the brakes
> >> were locking.
>
> >> Cost and some technical problems caused the shelving of this unit. But
> >> now, updated versions that give four-wheel skid control are offered on
> >> almost every car model, although initially they were available only on
> >> high-end cars like Lincoln and Mercedes, and a few European cars.
>
> >> Computerized brakes notwithstanding, there is a piece of advice about
> >> using brakes that's as relevant today as it was in 1909 when it was
> >> first published in The American Cyclopedia of the Automobile:
>
> >> "Good driving in traffic is shown by making the minimum use of brakes.
> >> The strain on passengers amounts to intense nervousness when the car
> >> is constantly driven so that the least alteration of direction or of
> >> pace on the part of any vehicle ahead results in the violent
> >> application of the brake."
>
> >> And so it will always be.
>
> >> >>On the back-end of a competition car, inboard disc brakes are often
> >> >>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
> >> >>competition drive systems, the discs are sometimes even found inboar=
d,
> >> >>at the front-end.
>
> >> >>There simply isn't one single reason NOT to have disc brakes.
>
> >> > There were even a few inboard DRUM brake vehicles built. Front drive
> >> >too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett?=
?
>
> >How does that make me wrong? Are you telling me that disc brakes are
> >not the preferred system for aircraft for all those reasons I laid
> >out? That it wasn't the aircraft people who developed many facets of
> >those systems?
>
> You stated, or appeared to state, that disc brakes were developed for
> aircraft use and they were lighter because of that.
>
> In that, you are wrong. If that's not what you MEANT, it IS what you
> SAID.
>
> >Tell you what..... there was a guy in my home-town in Holland who tied
> >his 1930-sh Somethingmobile to a tree with a rope so it wouldn't roll
> >down his laneway. Now I suppose you will give me a dissertation on
> >rope-brake systems through the frikkin' ages as well? What about
> >parachute brakes? There are all kinds of people using those. The
> >Veyron uses a big paddle that rises out of the back of the car to
> >assist slowing the thing down.
> >Anywhooo.. disc brakes are the preferred systems regardless whether or
> >not the Queen's carriage has a leather pad rubbing on the tyres.
>
> And I never said disc brakes were not better, overall than drums.
> All I said, which you have not been able to, and never will be able to
> prove me wrong, is that a drum brake, properly set up and adjusted,
> will stop a car more effectively on the first stop than a disc of the
> same size on the same car. It is a proven fact.
>
It is also a proven fact that zero rotation of a wheel can be achieved
with either a disc- or a drum brake and once that wheel has been
brought to a standstill ( leaving gobs of rubber on the road in the
process ) the difference becomes moot.
That leaves us with the ability to control the braking action on that
first stop you keep harping about and a disc brake is more
controllable than a drum brake.
This 'first stop' argument of yours is nothing but a straw man/red
herring combo.
Both a disc and a drum can stop a wheel dead.
If you believe that an 11" drum can out-brake, even on first stop, an
11" Brembo..... than you just keep on believing that because proving
that you can't.
On Sat, 16 Oct 2010 16:47:14 -0700, Larry Jaques
<[email protected]> wrote:
>On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE- <[email protected]>
>wrote:
>
>>On 10/14/10 2:24 PM, [email protected] wrote:
>>>>
>>>> How? Really. :-)
>>> You NEVER put side loads on a saw blade , particularly when running
>>> at speed.
>>
>>1. It wouldn't be running.
>>2. What I'm talking about could hardly be considered a load.
>
>Mike, typical caliper pads are unloaded by the play in the wheel
>bearings and a bit of runout on the disc. Unless you have some wobble
>in the blade, the pads will continue to drag on the blade. Just one
>more thing to work out. Build self-retracting pad retractors and...
>You'll be rich!
The design of a hydraulic brake caliper IS self retracting - based on
the flex in the square section "O" rings that seal the piston in the
bore.
On 10/13/2010 08:45 AM, Josepi wrote:
> I doubt most people use a pusher stick to cut plywood sheets.
First of all, he never said what kind of wood he was cutting, but from what he *did* say I
kinda doubt it was a sheet of plywood. Secondly, I said push "jig", not push "stick", and I
meant one of these:
http://www.tablesawpushstick.com/images/Pushstick%20Safety.jpg
Of course, right there in the description they're calling it a push "stick", which I think
is erroneous. When I hear "push stick", I think of one of these pieces of crap:
http://woodzone.com/Merchant2/graphics/00000001/push-stick.jpg
which I would *never* use; they give me the willies. For plywood, it's entirely plausible
to use a "push block"
http://woodzone.com/Merchant2/graphics/00000001/push-block.jpg
Unless it's a really big sheet of plywood, I use these whenever I can on larger panels to
keep them against the fence and my hands away from the blade. I use a GRR-Ripper for almost
everything else that requires close proximity to the blade.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
J. Clarke wrote:
>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>> my '76 Lincoln might surprise you.
>>>>>
>>>> Bill>
>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>J. Clarke>
>>> Why would something that can stop a 4000 pound car "snap" when called on
>>> to stop a 3 pound saw blade?
>> Bill>
>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>
>J. Clarke>
> To stop the saw in a fraction of a revolution, you need rapid
> application. A pyro will build pressure rapidly.
That is what I what I might expect to increase the probability of failure.
Given blade radius and density, and rpm, you could probably integrate to
compute the (foot-pounds of) energy that need to be stopped in a small
fraction of a second (I hope that the dust on the blade won't be an
issue). :) I've seen you post in another "forum" so I believe you are
up to the calculation. I do not have engineering background to back me
up, I'm just thinking it through with you and everyone else who is
reading. Evidently, you'll need to generate the equivalent of an equal
and opposite amount of energy. This means, I think, that you only get
the benefit of a "projection" (dot product) and not all of the force you
can apply to the side of the blade. My reasoning could definitely be
off, maybe a physicist or engineer could help out?
Regards,
Bill
On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
<[email protected]> wrote:
>On Sat, 16 Oct 2010 21:03:02 -0400, [email protected] wrote:
>
>>On Sat, 16 Oct 2010 17:03:40 -0700, Larry Jaques
>><[email protected]> wrote:
>>
>>>On Fri, 15 Oct 2010 11:54:46 -0400, [email protected] wrote:
>>>
>>>>On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
>>>><[email protected]> wrote:
>>>>
>>>>>Scott Lurndal wrote:
>>>>>
>>>>>>
>>>>>> On the other hand, disc brakes are designed so they don't lock up,
>>>>>> this includes the materials used as well plus the modern ABS
>>>>>> electronics.
>>>>>>
>>>>>
>>>>>No they aren't. ABS systems are designed to prevent the wheel from locking
>>>>>up, but disk brakes aren't. In fact, quite the opposite, they are designed
>>>>>to lock up but rely upon the ABS to govern them so they don't.
>>>> Not true. Drum brakes are much more powerfull on the first
>>>>application,
>>>
>>>False.
>>It has been proven over and over. They have, generally, more than
>>twice the friction area of a disk brake of the same diameter, and
>>being self energizing require much less pedal effort.
>
>I was comparing efficiencies for a given number of square inches of
>friction material, as noted further on in my last post. If you want
>to cheat, go ahead, but...
>
You didn't state you were comparing area of friction material, sonI'm
not cheating. Drum brakes have more friction material for the same
brake diameter.
>
>>Drum brakes do
>>not REQUIRE power boosters, while disk brakes, generally, are pittiful
>>without them. I'll put a 10 1/2 X2 1/2 drum brake up against an 11
>>inch disk any day of the week for a cold stop. and beat it hands down.
>
>And your point is? Drums are heavier, discs take more force, but both
>of those are attributes, not overall performance indicators. Most
>American cars are equipped with power brakes nowadays, and have been
>for at least 30 years.
And you are wrong on one other point. Disc brakes are generally
accepted as being HEAVIER than drum brakes of the same size, due to
the requirements of both the caliper and caliper frame vs stamped
backplate of a drum brake. The drum itself, compared to the rotor, can
go from being a virtual wash to the rotors being slightly lighter.
>
>
>>After 2 60mph stops within about 1 1/2 - 2 minutes the disk brake will
>>start gaining. By the third stop within 2 minutes it will be
>>outstopping the drum brake on a good day.
>
>In your dreams, clare. Discs will outstop the first stop, every time.
I've driven with massive disc brakes where if you didn't "warm them up
a bit" before the first really critical braking incident, you were in
DEEP trouble - but those were "competition" pads. I've driven LOTS of
cars without ABS, but power disc brakes, where you could NOT lock the
wheels on cool dry pavement, hot or cold. All the cars I've driven
with power drum brakes I could lock the brakes on any surface, at just
about any legal speed.
Those with non-power hydraulic drums could lock the wheels at in-town
speeds - even the old 850 mini.
That said - after several brake applications at highway speeds, ALL of
the drum equipped vehicles started requiring (significant) extra
stopping distance - even the Buick with the massively finned aluminum
drums, while the disc brake vehicles maintained stopping ability - and
in several cases, actually started stopping a whole lot better. With
the ceramic competition pads that, first stop, could hardly stop the
vehicle at 40mph, you could pretty easily lock the wheels at 80MPH and
higher once you had the rotors glowing a dull red.
>
>
>>3 hard stops in a row will make the disks shine (and mabee even glow)
>
>Haven't you ever seen red glowing brake drums on a truck headed down a
>mountain at night?
Yes I have - and when they are glowing, he's not far from trouble.
With disc brakes he's still got brakes
>
>
>>>>and more likely to lock up due to their self-energizing
>>>>servo action (virtually every drum brake on a vehicle in the last 40
>>>>years)
>>>
>>>True.
>>>
>>>
>>>>The only advantage of disks is faster cooling and less fade.
>>>
>>>The main advantage is efficiency. For a given poundage and square inch
>>>of pad, they're better than drums.
>>
>>
>>NOT when cold. Most disk brakes are actually pretty inneffective
>>before they get warmed up and they definitely require higher hydraulic
>>pressure to work, period.
>
>True, and it takes, what, about one quarter -second- of applied
>braking to warm them up? Gimme a break!
Can take a lot longer than that. Depending on the pad material, of
course.
>
>Ta!
On Oct 20, 9:00=A0am, "Josepi" <[email protected]> wrote:
> I assume that would all fit on the shaft between the motor and the blade =
or
> ar we drilling out the back endbell of the motor?
>
Never seen TEFC motors with a shaft on both ends?
On Oct 20, 3:07=A0pm, -MIKE- <[email protected]> wrote:
> On 10/20/10 1:44 PM, Robatoy wrote:
>
>
>
> > Yup, how to make a small fortune (By starting with a bigger one)
>
> I'm working on my second million.
> I gave up on the first.
>
Good one! (in my best Clouseau voice.. the Steven Martin version.)
I assume that would all fit on the shaft between the motor and the blade or
ar we drilling out the back endbell of the motor?
"Mike Marlow" <[email protected]> wrote in message
news:[email protected]...
Oh hell - that's easy. A set of torches, some steel, a little time, and
then paint to match. Don't forget the spring kit though.
Josepi wrote:
> OK, let's put drum brakes on the arbor of the motor!
>
> Somebody tell me how we are going to implement drum brakes on a T/S?
>
--
-Mike-
[email protected]
OK, let's put drum brakes on the arbor of the motor!
Somebody tell me how we are going to implement drum brakes on a T/S?
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
Is this horse dead YET? Please tell me it's dead...
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
A billion dallars ain't what it used to be either unless you are in the USA.
It changed everywhere else.
"Swingman" <[email protected]> wrote in message
news:[email protected]...
A million dollars ain't what it used to be ...
--
www.e-woodshop.net
Last update: 4/15/2010
KarlC@ (the obvious)
On 10/20/2010 2:07 PM, -MIKE- wrote:
> On 10/20/10 1:44 PM, Robatoy wrote:
>>
>> Yup, how to make a small fortune (By starting with a bigger one)
>
> I'm working on my second million.
> I gave up on the first.
You just haven't been around long enough.
Apparently I've made a couple ... although I never realized it due to
wife, kids, utility companies, insurance companies, house payments, car
payments, colleges, property taxes, Uncle Sam, et al.
A million dollars ain't what it used to be ...
--
www.e-woodshop.net
Last update: 4/15/2010
KarlC@ (the obvious)
On Oct 20, 2:19=A0pm, "Lew Hodgett" <[email protected]> wrote:
> "Robatoy" wrote:
> > Never seen TEFC motors with a shaft on both ends?
>
> -------------------------------------
> Been busy doing other things I see.
>
> Lew
Yup, how to make a small fortune (By starting with a bigger one)
Josepi wrote:
> OK, let's put drum brakes on the arbor of the motor!
>
> Somebody tell me how we are going to implement drum brakes on a T/S?
>
Oh hell - that's easy. A set of torches, some steel, a little time, and
then paint to match. Don't forget the spring kit though.
--
-Mike-
[email protected]
On Mon, 18 Oct 2010 20:31:44 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 18, 10:58Â pm, [email protected] wrote:
>> On Mon, 18 Oct 2010 13:34:38 -0700 (PDT), Robatoy
>>
>>
>>
>>
>>
>> <[email protected]> wrote:
>> >On Oct 18, 1:23Â pm, [email protected] wrote:
>> >> On Sun, 17 Oct 2010 22:59:03 -0400, [email protected] wrote:
>> >> >On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi" <[email protected]>
>> >> >wrote:
>>
>> >> >>Rust on the back disks from lack of heavy usage.
>>
>> >> >>I doubt it would be oak rust, though.
>>
>> >> >>"Robatoy" <[email protected]> wrote in message
>> >> >>news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com...
>> >> >>All you need to do is look at the history of the disc brake.
>> >> >>Lightweight, high-speed stopping power, reliable, operable in wet
>> >> >>conditions... IOW...aircraft.
>>
>> >> Â And you are WRONG again, Robotoy.
>> >> Disc brakes were invented before flight.
>>
>> >> The drum brake, as it is now known, became all-dominant in the United
>> >> States. In Europe, particularly in Great Britain, it had to share the
>> >> stage with disc brakes. Disc brakes became more or less standard on
>> >> European cars during the '50s, about 20 years before they were adopted
>> >> by American manufacturers in 1973.
>>
>> >> This is ironic, because the spot-type disc brake is an American
>> >> invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
>> >> electric car having front-wheel disc brakes.
>>
>> >> He made a large disc integral with the hub on each wheel.
>> >> Electromagnets were used to press smaller discs, lined with a friction
>> >> material, against spots on the rotating disc to bring the wheel to a
>> >> stop. Springs retracted the spot discs when current was interrupted.
>>
>> >> Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
>> >> Lanchester for a nonelectric spot disc braking system that's similar
>> >> in principle to what we have today. The biggest problem that
>> >> Lanchester encountered was noise. Metal-to-metal contact between his
>> >> copper linings and the metal disc caused an intense screech that sent
>> >> chills through anyone within earshot.
>>
>> >> The problem was solved in 1907 when Herbert Frood, another Englishman,
>> >> came up with the idea of lining pads with asbestos. The new material
>> >> was quickly adopted by car manufacturers on both drum and disc brakes.
>> >> Asbestos linings also outlasted other friction materials by a wide
>> >> margin. The 10,000-mile brake job had arrived.
>>
>> >> As roads improved and cars began to be driven at high speeds,
>> >> manufacturers recognized the need for even greater braking power. One
>> >> solution to the problem became apparent during the Elgin road Race of
>> >> 1915. A Duesenberg took the flats at 80 mph, then screeched to a
>> >> virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
>> >> such magnificent braking power was to simply use an internal brake on
>> >> each front wheel as well as each rear wheel.
>>
>> >> In 1918, a young inventor named Malcolm Lougheed (who later changed
>> >> the spelling of his name to Lockheed) applied hydraulics to braking.
>> >> He used cylinders and tubes to transmit fluid pressure against brake
>> >> shoes, pushing the shoes against the drums. In 1921, the first
>> >> passenger car to be equipped with four-wheel hydraulic brakes appeared
>> >> -- the Model A Duesenberg.
>>
>> >> Carmakers as a group were not quick to adopt hydraulics. Ten years
>> >> after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
>> >> Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
>> >> the others still had cable-operated mechanical brakes. In fact, it was
>> >> not until 1939 that Ford finally gave in, becoming the last major
>> >> manufacturer to switch to hydraulic brakes.
>>
>> >> The basic braking system we have today was pretty much in place by
>> >> 1921, including a refinement some regard as contemporary -- power
>> >> assist.
>>
>> >> Power assist, technically, dates back to 1903 when a car called the
>> >> Tincher used air brakes. But the first car to be equipped with a
>> >> vacuum-operated power booster similar to those we have today was the
>> >> 1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
>> >> the physical effort needed to apply brakes. Vacuum boosters from then
>> >> to now have similar designs.
>>
>> >> The first widespread deviation from vacuum power assist came about in
>> >> 1985. Some '85 GM cars use an electrically driven brake booster, which
>> >> is smaller and lighter than the conventional vacuum booster, giving an
>> >> all-hydraulic system. Some cars with antilock brakes also use
>> >> all-hydraulic systems.
>>
>> >> The first car to have self-adjusting brakes was the 1925 Cole. The
>> >> prototype for today's systems appeared on the 1946 Studebaker. The
>> >> mechanism by Wagner Electric Co., consisted of an adjusting wedge
>> >> under the influence of a tension spring. As linings wore, a plug
>> >> receded to move a pin and lever against the spring. This forced the
>> >> adjusting wedge against brake shoes, which expanded to keep linings at
>> >> a preset distance from the drums.
>>
>> >> As for the antilock (antiskid) units now available in the U.S., they
>> >> are hardly new. The first practical antiskid braking system, named
>> >> Maxaret, was developed in 1958 by the Road Research Laboratories in
>> >> Great Britain and was first applied to the Jensen FF sports sedan in
>> >> 1966.
>>
>> >> Three years later, in 1969, the Lincoln Continental Mark III was
>> >> equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
>> >> Sensors on the rear wheels transmitted signals to a transistorized
>> >> "computer" behind the glove box. The computer controlled a
>> >> vacuum-operated valve on the rear brake line to modulate pressure to
>> >> the rear brakes when the sensors told the computer that the brakes
>> >> were locking.
>>
>> >> Cost and some technical problems caused the shelving of this unit. But
>> >> now, updated versions that give four-wheel skid control are offered on
>> >> almost every car model, although initially they were available only on
>> >> high-end cars like Lincoln and Mercedes, and a few European cars.
>>
>> >> Computerized brakes notwithstanding, there is a piece of advice about
>> >> using brakes that's as relevant today as it was in 1909 when it was
>> >> first published in The American Cyclopedia of the Automobile:
>>
>> >> "Good driving in traffic is shown by making the minimum use of brakes.
>> >> The strain on passengers amounts to intense nervousness when the car
>> >> is constantly driven so that the least alteration of direction or of
>> >> pace on the part of any vehicle ahead results in the violent
>> >> application of the brake."
>>
>> >> And so it will always be.
>>
>> >> >>On the back-end of a competition car, inboard disc brakes are often
>> >> >>used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
>> >> >>competition drive systems, the discs are sometimes even found inboard,
>> >> >>at the front-end.
>>
>> >> >>There simply isn't one single reason NOT to have disc brakes.
>>
>> >> > There were even a few inboard DRUM brake vehicles built. Front drive
>> >> >too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??
>>
>> >How does that make me wrong? Are you telling me that disc brakes are
>> >not the preferred system for aircraft for all those reasons I laid
>> >out? That it wasn't the aircraft people who developed many facets of
>> >those systems?
>>
>> You stated, or appeared to state, that disc brakes were developed for
>> aircraft use and they were lighter because of that.
>>
>> In that, you are wrong. If that's not what you MEANT, it IS what you
>> SAID.
>>
>> >Tell you what..... there was a guy in my home-town in Holland who tied
>> >his 1930-sh Somethingmobile to a tree with a rope so it wouldn't roll
>> >down his laneway. Now I suppose you will give me a dissertation on
>> >rope-brake systems through the frikkin' ages as well? What about
>> >parachute brakes? There are all kinds of people using those. The
>> >Veyron uses a big paddle that rises out of the back of the car to
>> >assist slowing the thing down.
>> >Anywhooo.. disc brakes are the preferred systems regardless whether or
>> >not the Queen's carriage has a leather pad rubbing on the tyres.
>>
>> And I never said disc brakes were not better, overall than drums.
>> All I said, which you have not been able to, and never will be able to
>> prove me wrong, is that a drum brake, properly set up and adjusted,
>> will stop a car more effectively on the first stop than a disc of the
>> same size on the same car. It is a proven fact.
>>
>It is also a proven fact that zero rotation of a wheel can be achieved
>with either a disc- or a drum brake and once that wheel has been
>brought to a standstill ( leaving gobs of rubber on the road in the
>process ) the difference becomes moot.
>That leaves us with the ability to control the braking action on that
>first stop you keep harping about and a disc brake is more
>controllable than a drum brake.
>This 'first stop' argument of yours is nothing but a straw man/red
>herring combo.
>Both a disc and a drum can stop a wheel dead.
>If you believe that an 11" drum can out-brake, even on first stop, an
>11" Brembo..... than you just keep on believing that because proving
>that you can't.
Diameter for diameter, a drum brake has roughly TWICE the friction
area of a disc brake. Twice the friction area translates into twice
the stopping power with the same co-efficient of friction.
The reaction arm of a drum brake is also ALL at the outer radius of
the drum, while the average reaction arm on a disc brake is roughly
centered on the pad contact area, which is generally 1.5 to 2 inches
shorter than the radius of the rotor. The pad area inside the middle
provides less braking torque than average, while the area outside
provides more braking torque than the average, but still less than if
it was reacting at the outer radius of the rotor.
The disc brake also requires significantly more hydraulic action than
a Bendix style (or any other servo actuated) drum brake.
So for the same pedal effort (or boosted pressure with power brakes)
the drum brake WILL provide more stopping power. That cannot be
argued.
Period.
As soon as the drum starts getting hot it's braking power decreases,
and it continues to decrease as the temperature goes up. After a
fairly short time the disc brake starts to catch up, and quite soon it
ballances out and the lower initial braking power of the disc brake is
equal to the remaining braking power of the warmed up drum brake. Very
shortly there-after the braking power of the hot drum brake is reduced
to the point the "inferior" braking power of the disc brake now
greatly excedes the remaining braking power of the drum.
Add the effect of some of the higher performance pad materials, which
actually stop BETTER when hot, and the disc brake starts looking
pretty darn good in comparison to the overheated and now almost
totally ineffective drum brake.
Which does not change the FACT that the drum brake, within it's
(admittedly narrow) operating envelope, has superior braking power
compared to a disk of the same size.
And except for some of the more esoteric high priced (automotive)
brakes like (possibly) the Brembo, the combination of caliper, rotor,
and frame weights of a disc brake will outweigh all but the beafiest
drum brake implementation of the same diameter (by a significant
amount).
It is different in truck brakes, where the drums are REALLY heavy to
provide adequate thermal mass to keep the brakes from overheating to
the point of total failure in one moderate braking episode.
On Oct 19, 1:02=A0pm, [email protected] wrote:
>
> So for the same pedal effort (or boosted pressure with power brakes)
> the drum brake WILL provide more stopping power. That cannot be
> argued.
> Period.
I love the way you keep narrowing down the parameters of your
argument.
Now we have to apply the same foot-pressure!
But you failed to address the opening act of my position, and that is
that either system can lock up a wheel completely and do so quite
easily. After that zero rotation has been reached, it doesn't matter
one bit what is holding that wheel stationary, the tire/road is now
the friction contact patch.... unless we want to modulate the braking
action rapidly and accurately via an ABS (which was developed by
Dunlop for aircraft applications) system and good luck doing that with
drum brakes. (I am not saying that has never been done, cheapos do
drums on the back-wheels), but it isn't the norm on anything with some
level of performance, and for very good reasons.)
But you go ahead and promote your one-stop drum philosophy, I'll stick
to stuff that works.
All YOU have to do is remember that every time you use your brakes,
your life is your foot's hands.
Oh.. and I'm done with this discussion.
>
> And except for some of the more esoteric high priced (automotive)
> brakes like (possibly) the Brembo, the combination of caliper, rotor,
> and frame weights of a disc brake will outweigh all but the beafiest
> drum brake implementation of the same diameter (by a significant
> amount).
.......and what the hell does that have anything to do with the price
of fish?
On Oct 20, 3:15=A0pm, Swingman <[email protected]> wrote:
>
> A million dollars ain't what it used to be ...
>
...and THAT is a fact, sir. I remember thinking 20 years ago that a
million was a lot of money. Now you need 5 if you want to retire with
any kind of comfort.
.
.
.
..so uncomfortable it is then. <G>
On 10/19/2010 12:02 PM, [email protected], the Energizer Bunny, wrote another
version of his book using slightly different words:
<SNIP>
Is this horse dead YET? Please tell me it's dead...
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/19/10 10:32 PM, [email protected] wrote:
> And the website I first referenced was clearly plagerised.
> I did not reference it because I KNEW it was not the original when I
> originally downloaded the material.
>
You're very good at throwing in minutia to slightly change the details
in an ill fated attempt at saving face. You should be a defense
attorney. :-)
It doesn't matter if the website you cut and pasted from was the
original author or not.
It's hard to find *anything* on the internet that hasn't been copied and
passed around from site to site. I find stuff I wrote on my website, ten
years ago, pasted on websites all over the world.
What matters is that you were trying pass it off as your own thought.
Have you seen Good Will Hunting?
> When called on it I investigated and found out who the ORIGINAL author
> was and gave credit where credit was due.
>
Credit to the original author in the context of this debate isn't nearly
as important as simply writing, "I copied the following from a mechanics
website."
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/20/10 1:44 PM, Robatoy wrote:
>
> Yup, how to make a small fortune (By starting with a bigger one)
I'm working on my second million.
I gave up on the first.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
Not saying I agree with using drum brakes in this application, but one
possible place is at the pulley end of the blade arbor. I have seen small
brake assemblies that were actually built into pulleys, though much larger
than the ones used on table saws.
--
There are no stupid questions, but there are lots of stupid answers.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar. org
In article <[email protected]>
Steve Turner <[email protected]> writes:
>On 10/19/2010 12:02 PM, [email protected], the Energizer Bunny, wrote another
>version of his book using slightly different words:
><SNIP>
>
>Is this horse dead YET? Please tell me it's dead...
But what about the beating? It is going on, and we need some way to stop it.
If only there were braking systems of some sort . . . .
--
Drew Lawson | Though it's just a memory,
| some memories last forever
On 10/21/2010 9:14 PM, Drew Lawson wrote:
> In article<[email protected]>
> Steve Turner<[email protected]> writes:
>> On 10/19/2010 12:02 PM, [email protected], the Energizer Bunny, wrote another
>> version of his book using slightly different words:
>> <SNIP>
>>
>> Is this horse dead YET? Please tell me it's dead...
>
> But what about the beating? It is going on, and we need some way to stop it.
> If only there were braking systems of some sort . . . .
Ayiiiieeee!!! :-)
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On Tue, 19 Oct 2010 21:44:18 -0500, -MIKE- <[email protected]>
wrote:
>On 10/19/10 8:50 PM, Josepi wrote:
>> Bullshit. Where you come from, and most others, coying somebody else's work
>> is called a "Reference"
>>
>
>I'm assuming you at least got though middle school where the subject was
>covered, but here's a refresher...
>Giving CREDIT to the original author is called a reference.
>Copying and pasting word for word without giving credit to the author is
>plagiarism.
>
>
And the website I first referenced was clearly plagerised.
I did not reference it because I KNEW it was not the original when I
originally downloaded the material.
When called on it I investigated and found out who the ORIGINAL author
was and gave credit where credit was due.
>> Constantly disputing anything and everything for a response that isn't
>> related to the subject at hand is called.... "Trolling"
>>
>
>Thanks for finally admitting it.
>
>
>> You don't want to discuss anything at hand, you just want attention and
>> defences.
>
>Even if that were true, at least I use my own material.
On Fri, 22 Oct 2010 02:14:58 +0000 (UTC), [email protected] (Drew
Lawson) wrote:
>In article <[email protected]>
> Steve Turner <[email protected]> writes:
>>On 10/19/2010 12:02 PM, [email protected], the Energizer Bunny, wrote another
>>version of his book using slightly different words:
>><SNIP>
>>
>>Is this horse dead YET? Please tell me it's dead...
>
>But what about the beating? It is going on, and we need some way to stop it.
>If only there were braking systems of some sort . . . .
Keep drumming that in, boy.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
On Sat, 16 Oct 2010 21:03:02 -0400, [email protected] wrote:
>On Sat, 16 Oct 2010 17:03:40 -0700, Larry Jaques
><[email protected]> wrote:
>
>>On Fri, 15 Oct 2010 11:54:46 -0400, [email protected] wrote:
>>
>>>On Thu, 14 Oct 2010 22:06:25 -0400, "Mike Marlow"
>>><[email protected]> wrote:
>>>
>>>>Scott Lurndal wrote:
>>>>
>>>>>
>>>>> On the other hand, disc brakes are designed so they don't lock up,
>>>>> this includes the materials used as well plus the modern ABS
>>>>> electronics.
>>>>>
>>>>
>>>>No they aren't. ABS systems are designed to prevent the wheel from locking
>>>>up, but disk brakes aren't. In fact, quite the opposite, they are designed
>>>>to lock up but rely upon the ABS to govern them so they don't.
>>> Not true. Drum brakes are much more powerfull on the first
>>>application,
>>
>>False.
>It has been proven over and over. They have, generally, more than
>twice the friction area of a disk brake of the same diameter, and
>being self energizing require much less pedal effort.
I was comparing efficiencies for a given number of square inches of
friction material, as noted further on in my last post. If you want
to cheat, go ahead, but...
>Drum brakes do
>not REQUIRE power boosters, while disk brakes, generally, are pittiful
>without them. I'll put a 10 1/2 X2 1/2 drum brake up against an 11
>inch disk any day of the week for a cold stop. and beat it hands down.
And your point is? Drums are heavier, discs take more force, but both
of those are attributes, not overall performance indicators. Most
American cars are equipped with power brakes nowadays, and have been
for at least 30 years.
>After 2 60mph stops within about 1 1/2 - 2 minutes the disk brake will
>start gaining. By the third stop within 2 minutes it will be
>outstopping the drum brake on a good day.
In your dreams, clare. Discs will outstop the first stop, every time.
>3 hard stops in a row will make the disks shine (and mabee even glow)
Haven't you ever seen red glowing brake drums on a truck headed down a
mountain at night?
>>>and more likely to lock up due to their self-energizing
>>>servo action (virtually every drum brake on a vehicle in the last 40
>>>years)
>>
>>True.
>>
>>
>>>The only advantage of disks is faster cooling and less fade.
>>
>>The main advantage is efficiency. For a given poundage and square inch
>>of pad, they're better than drums.
>
>
>NOT when cold. Most disk brakes are actually pretty inneffective
>before they get warmed up and they definitely require higher hydraulic
>pressure to work, period.
True, and it takes, what, about one quarter -second- of applied
braking to warm them up? Gimme a break!
Ta!
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
On Mon, 18 Oct 2010 13:12:17 -0500, -MIKE- <[email protected]>
wrote:
>On 10/18/10 1:04 PM, [email protected] wrote:
>> On Mon, 18 Oct 2010 12:27:39 -0500, -MIKE-<[email protected]>
>> wrote:
>>>> Are you going to at least give credit to the websites from which you
>>> cut-n-pasted all this?
>> Sorry - I believe it was originally published on the internet by
>> motorera.com
>> Not sure where it came from before that, as I have seen it in several
>> different places.
>
>Riiiiiiight. You're saying you typed it out, verbatim, from memory
>Rainman? :-p
No, but I have a heck of a lot of automotive stuff on my hard drive,
from many sources - much of it teaching/training materials.
I also have a failry decent library of printed material.
A lot of stuff on automotive, computer and aircraft technology.
Woodworking is only one of my hobbies
On Mon, 18 Oct 2010 13:12:17 -0500, -MIKE- <[email protected]>
wrote:
>On 10/18/10 1:04 PM, [email protected] wrote:
>> On Mon, 18 Oct 2010 12:27:39 -0500, -MIKE-<[email protected]>
>> wrote:
>>>> Are you going to at least give credit to the websites from which you
>>> cut-n-pasted all this?
>> Sorry - I believe it was originally published on the internet by
>> motorera.com
>> Not sure where it came from before that, as I have seen it in several
>> different places.
>
>Riiiiiiight. You're saying you typed it out, verbatim, from memory
>Rainman? :-p
OK, I found the "original" source - Pop Mechanics July 1978 -Brakes
- A Century of Progress.by Morton Schultz. (starts on Page 132)
The MotorEra site does not attribute the text to Mr Schultz.
And as for an earlier question - re electric brakes, Seimens is
working on an EWB system - electronic wedge brake - that uses a
moroized wedge to apply a disk brake. This will allow true antilock
braking where the system pre-emtively reduces braking pressure BEFORE
the wheel locks, and it can react much more quickly than hydraulics.
On Fri, 15 Oct 2010 11:16:56 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 15, 1:31 pm, "Josepi" <[email protected]> wrote:
>> Sorry you asre twisting words and playing with semantics.
>>
>> Brake lock-up is not when the wheel stops turning. It is when the brakes
>> will not let go and cease to act linearly.
>>
>> ABS was not created for brake lock-up. ABS would not help this problem.
>>
>
>You are completely and totally wrong and incorrect.
>
>ABS, by definition, stands for Anti-lock Braking System. Now apply
>this little bit of knowledge to your position, and you will see that
>you are wrong, incorrect and mistaken.
>Brake lock-up is lock-up caused by a brake, NOT a brake locking up.
> ABS does not stand for Anti Brake Locking Up System.
>With me yet?
>
>Also, when you find yourself in a hole, stop digging.
PDFTFT
--
Do not taunt Happy Fun Ball!
On Oct 17, 2:43=A0pm, [email protected] wrote:
>
> I've driven an X1/9 too -
Who would ADMIT to such a thing.....?
On Fri, 15 Oct 2010 17:55:13 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>, [email protected] says...
>>
>> The name "anti-lock" is a misnomer as the brakes successively lock and
>> release each pulse. On each release steering control is regained. Braking
>> distance is not improved as admitted in later research.
>
>We all know how it works, and what "later research" is this that shows
>that braking distance is not improved on slippery surfaces?
>
>Every test I've seen has shown that an _expert_ driver having made a few
>practice stops on the specific surface on the specific day in the
>specific vehicle can beat it by a very small margin on _dry_ surfaces,
>but not without practice and not on wet, icy, or other kinds of reduced-
>traction surfaces.
>
>ABS does not engage until the driver has already screwed up.
>>
>> "J. Clarke" <[email protected]> wrote in message
>> news:[email protected]...
>> They're not "designed to lock up", they're designed as a compromise
>> between maximum braking force, fade, pad wear, weight, and cost. Most
>> disk brakes can be locked.
>>
>> ABS is intended to save your ass when there's poor traction by
>> preventing lock--it will also prevent lock on good surfaces but
>> generally isn't needed for that purpose.
>
Depends what conditions you drive in.
With wide tires in wet sloppy slush, a car with ABS will just continue
going straight. Without ABS I can stop it every time - mabee sideways
part of the way, but at least partially in control. Say within 60
feet, while with ABS I'm still merrily sliding /rolling along with all
4 circuits of the ABS clacking away 150 feet down the road.
Being able to actually lock the wheels to scrub down through the crap
to pavement is almost a necessity under those conditions.
No ABS on my PT cruiser and it's broken on the Mystique - and will
stay that way.
On Fri, 15 Oct 2010 18:04:15 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Fri, 15 Oct 2010 12:54:44 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>> >Josepi wrote:
>> >
>> >> Disc brake were around for a lot longer than the ABS systems were ever
>> >> implemented.
>> >> Disc brakes were not sdesigned to "lock up" but rather be more linear
>> >> than shoe brake systems, and fade less.
>> >>
>> >
>> >You are correct that disk brakes have been around a lot longer than ABS has,
>> >but if you believe that disk brakes will not lock up then you simply need to
>> >drive a car that pre-dates ABS. Disk brakes will most certainly lock up.
>> >Why do you think ABS exists?
>> Because most drivers don't (according to our governments and highway
>> safety people) have the brains to release their brakes when the wheels
>> start to slide.
>
>The best driver in the world can't sense lock and modulate the pedal as
>quickly or consistently as a computer with a sensor on each wheel.
Which does not NECESSARILY translate into shorter stopping distances
under all (low traction) conditions
On Sun, 17 Oct 2010 13:01:35 GMT, [email protected] (Doug Miller)
wrote:
>In article <[email protected]>, [email protected] wrote:
>
>>It has been proven over and over. They have, generally, more than
>>twice the friction area of a disk brake of the same diameter, and
>>being self energizing require much less pedal effort. Drum brakes do
>>not REQUIRE power boosters, while disk brakes, generally, are pittiful
>>without them. I'll put a 10 1/2 X2 1/2 drum brake up against an 11
>>inch disk any day of the week for a cold stop. and beat it hands down.
>
>Complete and utter nonsense. It's evident that you've never driven a car with
>unassisted disc brakes. I owned one for three years (Fiat X-1/9), and I can
>attest that the disc brakes in that car were *far* more effective than the
>drum brakes, assisted or not, in any other vehicle I've ever driven.
I've driven an X1/9 too - and a 128S. Brakes were not the strong point
of either one. The 1/9 had 4 wheel disks - little shitty 9 inchers
that seized up if you got within 6 feet of a salted road.
Edmund's tech center states "the current rear drum brake systems on
today's cars would provide better stopping performance then the front
disc setups of the '70s."
Disc brakes require higher static line pressures for effective braking
torque to be experienced.
Most drum brake systems have Servo brakes. In a servo brake system, as
hydraulic pressure is increased in the wheel cylinder, the push rod is
extended & pushes against the primary shoe, moving the primary &
secondary shoe in an arc. The end of the secondary shoe is anchored
against an anchor pin at the top of the brake cluster [ backing
plate]. This results in the primary & secondary shoes of the brake
cluster having LEVERED force applied to the brake shoes.
Because of this levered force, developed at the drum brake cluster,
drum brakes will give better braking torque, at a lower hydraulic
pressure & are therefore more effective'
In addition to this, the surface area of the pads on a drum brake
system is normally larger than that of a comparable disc brake system.
With a comparable coefficient of friction for the drum & disc brake
components, the greater surface area of the drum system will give
greater frictional resistance due to the larger surface area of the
pads.
>
>>After 2 60mph stops within about 1 1/2 - 2 minutes the disk brake will
>>start gaining. By the third stop within 2 minutes it will be
>>outstopping the drum brake on a good day.
>
>Disc brakes outstop drum brakes, on good days or bad, beginning with the first
>stop.
>
>Another major advantage of discs over drums is that they still work -- first
>time -- after driving through a puddle, because the water can drain away.
I'm not saying drums are better than discs - for many reasons - mostly
heat related - but the fact remains - for the FIRST stop, size for
size a drum brake is more effective. It takes less hydraulic pressure
to provide higher braking force than a disc. That is just fact. Disc
brakes have a lot of advantages - they don't fade nearly as quickly
when heated up - they are more "linear" and less prone to grabbing,
they are self adjusting, and easier to service.
Drums have only a few advantages - they are lighter, they are easier
to combine parking brake function, they require less hydraulic
pressure for the same stopping power, and they are cheaper to build.
All this observation comes from decades in the automotive service
buisiness and years of competition driving.
J. Clarke wrote:
>>> As is done when, say, you are pushing a bit of wood into the saw and
>>> it jerks out of place and you essentially "fall" forward now that the
>>> wood is no longer offering resistance?
>>
>> I've read that about five times and have tried to visualize what you're
>> talking
>> about, but I'm still puzzled.
Think about what would happen if you were walking with a cane, and the
tip of the cane slipped on some ice. It's analogous.
Bill
On 10/13/10 9:43 AM, J. Clarke wrote:
> In article<[email protected]>, [email protected] says...
>>
>> J. Clarke wrote:
>>> In article<[email protected]>, [email protected] says...
>>>>
>>>> J. Clarke wrote:
>>>>> In article<[email protected]>,
>>>>> [email protected] says...
>>>>>>
>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>>>
>>>>>>> J. Clarke wrote:
>>>>>>>> In article<[email protected]>, [email protected] says...
>>>>>>>>>
>>>>>>>>> I would think that an emergency stop mechanism would be a whole different
>>>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>>>
>>>>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>>>>>>>>> would be OK too. These two situations would require different tactics.
>>>>>>>>>
>>>>>>>>> A dynamic electronic brake could vary the intensity for the two different
>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>>>>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
>>>>>>>>> replaced frequently.
>>>>>>>>
>>>>>>>> So how much power do you have to put into that electronic brake to stop
>>>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>>>
>>>>>>>> And why would a caliper not last long? A set of brake pads on a car
>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>>>>>>>> a lot more of a workout that they would stopping a little bitty saw
>>>>>>>> blade that masses less than 1/1000 as much.
>>>>>>>
>>>>>>> The physics on that seem interesting. A little like stopping a speeding
>>>>>>> bullet on a dime--it challenges my imagination. Probably not quite as
>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
>>>>>>> either.
>>>>>>>
>>>>>>> Bill
>>>>>> No way a caliper could stop the blade in even 4X the time the
>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>>>>>> the blade would be quite problematic - with dust decreasing the
>>>>>> stopping efficiency by a very large margin.
>>>>>
>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>> my '76 Lincoln might surprise you.
>>>>>
>>>>
>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>
>>> Why would something that can stop a 4000 pound car "snap" when called on
>>> to stop a 3 pound saw blade?
>>
>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>
> To stop the saw in a fraction of a revolution, you need rapid
> application. A pyro will build pressure rapidly.
I didn't think we were talking about an emergency stop.
AFAIK, we're discussing a convenience stop which, in my opinion, would
be satisfactorily done in a couple seconds, not milliseconds.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Sun, 17 Oct 2010 09:44:09 -0700, Larry Jaques
<[email protected]> wrote:
>On Sat, 16 Oct 2010 21:04:36 -0400, [email protected] wrote:
>
>>On Sat, 16 Oct 2010 16:47:14 -0700, Larry Jaques
>><[email protected]> wrote:
>>
>>>On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE- <[email protected]>
>>>wrote:
>>>
>>>>On 10/14/10 2:24 PM, [email protected] wrote:
>>>>>>
>>>>>> How? Really. :-)
>>>>> You NEVER put side loads on a saw blade , particularly when running
>>>>> at speed.
>>>>
>>>>1. It wouldn't be running.
>>>>2. What I'm talking about could hardly be considered a load.
>>>
>>>Mike, typical caliper pads are unloaded by the play in the wheel
>>>bearings and a bit of runout on the disc. Unless you have some wobble
>>>in the blade, the pads will continue to drag on the blade. Just one
>>>more thing to work out. Build self-retracting pad retractors and...
>>>You'll be rich!
>> The design of a hydraulic brake caliper IS self retracting - based on
>>the flex in the square section "O" rings that seal the piston in the
>>bore.
>
>Only to an engineer in an office, not in real life.
>
>Go jack up a disc braked car and spin the wheel. Now climb inside and
>give the brake pedal a good stomp. Then spin the wheel again. You'll
>find that they're not quite self-retracting. A quick pop on the side
>(top or bottom) of the tire with your hand will release it, though.
A dual piston or 4 piston caliper will release virtually immediately.
A single piston caliper will release the inside pad immediately, and
depending on the slider design, can also release the outer pad
immediately (rubber bushed pin type sliders)
Those with metal plate type sliders will not release the outside pad
without a bit of "external help" - and if those sliders are corroded
and/or inadequately lubricated, often not even WITH significant
external help.
If you get corrosion on the pistons, or crud buildup around the
piston, the self retracting is a lot less effective.
On Sat, 16 Oct 2010 21:04:36 -0400, [email protected] wrote:
>On Sat, 16 Oct 2010 16:47:14 -0700, Larry Jaques
><[email protected]> wrote:
>
>>On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE- <[email protected]>
>>wrote:
>>
>>>On 10/14/10 2:24 PM, [email protected] wrote:
>>>>>
>>>>> How? Really. :-)
>>>> You NEVER put side loads on a saw blade , particularly when running
>>>> at speed.
>>>
>>>1. It wouldn't be running.
>>>2. What I'm talking about could hardly be considered a load.
>>
>>Mike, typical caliper pads are unloaded by the play in the wheel
>>bearings and a bit of runout on the disc. Unless you have some wobble
>>in the blade, the pads will continue to drag on the blade. Just one
>>more thing to work out. Build self-retracting pad retractors and...
>>You'll be rich!
> The design of a hydraulic brake caliper IS self retracting - based on
>the flex in the square section "O" rings that seal the piston in the
>bore.
Only to an engineer in an office, not in real life.
Go jack up a disc braked car and spin the wheel. Now climb inside and
give the brake pedal a good stomp. Then spin the wheel again. You'll
find that they're not quite self-retracting. A quick pop on the side
(top or bottom) of the tire with your hand will release it, though.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
On Sat, 16 Oct 2010 21:01:12 -0500, -MIKE- <[email protected]>
wrote:
>On 10/16/10 6:47 PM, Larry Jaques wrote:
>> On Thu, 14 Oct 2010 15:05:50 -0500, -MIKE-<[email protected]>
>> wrote:
>>
>>> On 10/14/10 2:24 PM, [email protected] wrote:
>>>>>
>>>>> How? Really. :-)
>>>> You NEVER put side loads on a saw blade , particularly when running
>>>> at speed.
>>>
>>> 1. It wouldn't be running.
>>> 2. What I'm talking about could hardly be considered a load.
>>
>> Mike, typical caliper pads are unloaded by the play in the wheel
>> bearings and a bit of runout on the disc.
>
>Please note that I never bought in to the caliper thing, before you
>include me in an argument I've opted out of. :-)
>
>I am still talking about a bicycle style spring and/or solenoid/magnetic
>brake.
Wull, nevermindthen.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
-MIKE- wrote:
> On 10/13/10 9:43 AM, J. Clarke wrote:
>> In article<[email protected]>, [email protected] says...
>>>
>>> J. Clarke wrote:
>>>> In article<[email protected]>, [email protected] says...
>>>>>
>>>>> J. Clarke wrote:
>>>>>> In article<[email protected]>,
>>>>>> [email protected] says...
>>>>>>>
>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>>>>
>>>>>>>> J. Clarke wrote:
>>>>>>>>> In article<[email protected]>, [email protected]
>>>>>>>>> says...
>>>>>>>>>>
>>>>>>>>>> I would think that an emergency stop mechanism would be a
>>>>>>>>>> whole different
>>>>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>>>>
>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
>>>>>>>>>> stop the blade
>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
>>>>>>>>>> blade rotations
>>>>>>>>>> would be OK too. These two situations would require different
>>>>>>>>>> tactics.
>>>>>>>>>>
>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
>>>>>>>>>> two different
>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
>>>>>>>>>> caliper probably
>>>>>>>>>> wouldn't last long in everyday usage and would need to be
>>>>>>>>>> adjusted and/or
>>>>>>>>>> replaced frequently.
>>>>>>>>>
>>>>>>>>> So how much power do you have to put into that electronic brake
>>>>>>>>> to stop
>>>>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>>>>
>>>>>>>>> And why would a caliper not last long? A set of brake pads on a
>>>>>>>>> car
>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a
>>>>>>>>> Hell of
>>>>>>>>> a lot more of a workout that they would stopping a little bitty
>>>>>>>>> saw
>>>>>>>>> blade that masses less than 1/1000 as much.
>>>>>>>>
>>>>>>>> The physics on that seem interesting. A little like stopping a
>>>>>>>> speeding
>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
>>>>>>>> quite as
>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
>>>>>>>> try that
>>>>>>>> either.
>>>>>>>>
>>>>>>>> Bill
>>>>>>> No way a caliper could stop the blade in even 4X the time the
>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>>>>>>> the blade would be quite problematic - with dust decreasing the
>>>>>>> stopping efficiency by a very large margin.
>>>>>>
>>>>>> I suspect that a small pyrotechnic pressurizing one of the
>>>>>> calipers off
>>>>>> my '76 Lincoln might surprise you.
>>>>>>
>>>>>
>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>>
>>>> Why would something that can stop a 4000 pound car "snap" when
>>>> called on
>>>> to stop a 3 pound saw blade?
>>>
>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>
>> To stop the saw in a fraction of a revolution, you need rapid
>> application. A pyro will build pressure rapidly.
>
> I didn't think we were talking about an emergency stop.
> AFAIK, we're discussing a convenience stop which, in my opinion, would
> be satisfactorily done in a couple seconds, not milliseconds.
>
I thought we were discussing a stop on the same order as SawStop.
I didn't read every post in the thread.
Bill
On 10/13/10 11:30 AM, Bill wrote:
> -MIKE- wrote:
>> On 10/13/10 9:43 AM, J. Clarke wrote:
>>> In article<[email protected]>, [email protected] says...
>>>>
>>>> J. Clarke wrote:
>>>>> In article<[email protected]>, [email protected] says...
>>>>>>
>>>>>> J. Clarke wrote:
>>>>>>> In article<[email protected]>,
>>>>>>> [email protected] says...
>>>>>>>>
>>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>>>>>
>>>>>>>>> J. Clarke wrote:
>>>>>>>>>> In article<[email protected]>, [email protected]
>>>>>>>>>> says...
>>>>>>>>>>>
>>>>>>>>>>> I would think that an emergency stop mechanism would be a
>>>>>>>>>>> whole different
>>>>>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>>>>>
>>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
>>>>>>>>>>> stop the blade
>>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
>>>>>>>>>>> blade rotations
>>>>>>>>>>> would be OK too. These two situations would require different
>>>>>>>>>>> tactics.
>>>>>>>>>>>
>>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
>>>>>>>>>>> two different
>>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
>>>>>>>>>>> caliper probably
>>>>>>>>>>> wouldn't last long in everyday usage and would need to be
>>>>>>>>>>> adjusted and/or
>>>>>>>>>>> replaced frequently.
>>>>>>>>>>
>>>>>>>>>> So how much power do you have to put into that electronic brake
>>>>>>>>>> to stop
>>>>>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>>>>>
>>>>>>>>>> And why would a caliper not last long? A set of brake pads on a
>>>>>>>>>> car
>>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a
>>>>>>>>>> Hell of
>>>>>>>>>> a lot more of a workout that they would stopping a little bitty
>>>>>>>>>> saw
>>>>>>>>>> blade that masses less than 1/1000 as much.
>>>>>>>>>
>>>>>>>>> The physics on that seem interesting. A little like stopping a
>>>>>>>>> speeding
>>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
>>>>>>>>> quite as
>>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
>>>>>>>>> try that
>>>>>>>>> either.
>>>>>>>>>
>>>>>>>>> Bill
>>>>>>>> No way a caliper could stop the blade in even 4X the time the
>>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad"
>>>>>>>> and
>>>>>>>> the blade would be quite problematic - with dust decreasing the
>>>>>>>> stopping efficiency by a very large margin.
>>>>>>>
>>>>>>> I suspect that a small pyrotechnic pressurizing one of the
>>>>>>> calipers off
>>>>>>> my '76 Lincoln might surprise you.
>>>>>>>
>>>>>>
>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>>>
>>>>> Why would something that can stop a 4000 pound car "snap" when
>>>>> called on
>>>>> to stop a 3 pound saw blade?
>>>>
>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>>
>>> To stop the saw in a fraction of a revolution, you need rapid
>>> application. A pyro will build pressure rapidly.
>>
>> I didn't think we were talking about an emergency stop.
>> AFAIK, we're discussing a convenience stop which, in my opinion, would
>> be satisfactorily done in a couple seconds, not milliseconds.
>>
>
> I thought we were discussing a stop on the same order as SawStop.
> I didn't read every post in the thread.
>
> Bill
>
Someone brought SawStop into the discussion, which took things on a
tangent.
We started out discussing the OP's link to a set of motor reversing
instructions as a way to slow down the blade for convenience. Then I
proposed the use of a bicycle brake... and things went from there.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/13/2010 12:00 PM, Bill wrote:
> -MIKE- wrote:
>> Someone brought SawStop into the discussion, which took things on a
>> tangent.
>> We started out discussing the OP's link to a set of motor reversing
>> instructions as a way to slow down the blade for convenience. Then I
>> proposed the use of a bicycle brake... and things went from there.
>>
> Properly done, I bicycle brake sounds like a good idea! I'd hate to read about flying parts.
AHEM. I believe *I* was the one who proposed the use of the bicycle brake. That -MIKE-
character is trying to steal my idea. :-)
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
-MIKE- wrote:
> On 10/13/10 11:30 AM, Bill wrote:
>> -MIKE- wrote:
>>> On 10/13/10 9:43 AM, J. Clarke wrote:
>>>> In article<[email protected]>, [email protected] says...
>>>>>
>>>>> J. Clarke wrote:
>>>>>> In article<[email protected]>, [email protected] says...
>>>>>>>
>>>>>>> J. Clarke wrote:
>>>>>>>> In article<[email protected]>,
>>>>>>>> [email protected] says...
>>>>>>>>>
>>>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>>>>>>
>>>>>>>>>> J. Clarke wrote:
>>>>>>>>>>> In article<[email protected]>, [email protected]
>>>>>>>>>>> says...
>>>>>>>>>>>>
>>>>>>>>>>>> I would think that an emergency stop mechanism would be a
>>>>>>>>>>>> whole different
>>>>>>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>>>>>>
>>>>>>>>>>>> For a finger saver an emergency stop mechanism would have to
>>>>>>>>>>>> stop the blade
>>>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen
>>>>>>>>>>>> blade rotations
>>>>>>>>>>>> would be OK too. These two situations would require different
>>>>>>>>>>>> tactics.
>>>>>>>>>>>>
>>>>>>>>>>>> A dynamic electronic brake could vary the intensity for the
>>>>>>>>>>>> two different
>>>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A
>>>>>>>>>>>> caliper probably
>>>>>>>>>>>> wouldn't last long in everyday usage and would need to be
>>>>>>>>>>>> adjusted and/or
>>>>>>>>>>>> replaced frequently.
>>>>>>>>>>>
>>>>>>>>>>> So how much power do you have to put into that electronic brake
>>>>>>>>>>> to stop
>>>>>>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>>>>>>
>>>>>>>>>>> And why would a caliper not last long? A set of brake pads on a
>>>>>>>>>>> car
>>>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a
>>>>>>>>>>> Hell of
>>>>>>>>>>> a lot more of a workout that they would stopping a little bitty
>>>>>>>>>>> saw
>>>>>>>>>>> blade that masses less than 1/1000 as much.
>>>>>>>>>>
>>>>>>>>>> The physics on that seem interesting. A little like stopping a
>>>>>>>>>> speeding
>>>>>>>>>> bullet on a dime--it challenges my imagination. Probably not
>>>>>>>>>> quite as
>>>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to
>>>>>>>>>> try that
>>>>>>>>>> either.
>>>>>>>>>>
>>>>>>>>>> Bill
>>>>>>>>> No way a caliper could stop the blade in even 4X the time the
>>>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad"
>>>>>>>>> and
>>>>>>>>> the blade would be quite problematic - with dust decreasing the
>>>>>>>>> stopping efficiency by a very large margin.
>>>>>>>>
>>>>>>>> I suspect that a small pyrotechnic pressurizing one of the
>>>>>>>> calipers off
>>>>>>>> my '76 Lincoln might surprise you.
>>>>>>>>
>>>>>>>
>>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know
>>>>>>> for
>>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>>>>
>>>>>> Why would something that can stop a 4000 pound car "snap" when
>>>>>> called on
>>>>>> to stop a 3 pound saw blade?
>>>>>
>>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>>>
>>>> To stop the saw in a fraction of a revolution, you need rapid
>>>> application. A pyro will build pressure rapidly.
>>>
>>> I didn't think we were talking about an emergency stop.
>>> AFAIK, we're discussing a convenience stop which, in my opinion, would
>>> be satisfactorily done in a couple seconds, not milliseconds.
>>>
>>
>> I thought we were discussing a stop on the same order as SawStop.
>> I didn't read every post in the thread.
>>
>> Bill
>>
>
> Someone brought SawStop into the discussion, which took things on a
> tangent.
> We started out discussing the OP's link to a set of motor reversing
> instructions as a way to slow down the blade for convenience. Then I
> proposed the use of a bicycle brake... and things went from there.
>
Properly done, I bicycle brake sounds like a good idea! I'd hate to
read about flying parts.
Bill
On 10/13/10 12:06 PM, Steve Turner wrote:
> On 10/13/2010 12:00 PM, Bill wrote:
>> -MIKE- wrote:
>>> Someone brought SawStop into the discussion, which took things on a
>>> tangent.
>>> We started out discussing the OP's link to a set of motor reversing
>>> instructions as a way to slow down the blade for convenience. Then I
>>> proposed the use of a bicycle brake... and things went from there.
>>>
>> Properly done, I bicycle brake sounds like a good idea! I'd hate to
>> read about flying parts.
>
> AHEM. I believe *I* was the one who proposed the use of the bicycle
> brake. That -MIKE- character is trying to steal my idea. :-)
>
Welllll, looks like I own someone a beer.
Yeppers, I said, "...aftermarket saw brake, under the table.... pads or
rollers or whatever, that would squeeze the blade," and then you brought
up the bike brake.
A good inventor is a better thief. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
J. Clarke wrote:
> In article<[email protected]>, [email protected] says...
>>
>> J. Clarke wrote:
>>
>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>>>> my '76 Lincoln might surprise you.
>>>>>>>
>>>>>> Bill>
>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>
>>>>> J. Clarke>
>>>>> Why would something that can stop a 4000 pound car "snap" when called on
>>>>> to stop a 3 pound saw blade?
>>
>>>> Bill>
>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>>
>> >J. Clarke>
>>> To stop the saw in a fraction of a revolution, you need rapid
>>> application. A pyro will build pressure rapidly.
>>
>> That is what I what I might expect to increase the probability of failure.
>>
>> Given blade radius and density, and rpm, you could probably integrate to
>> compute the (foot-pounds of) energy that need to be stopped in a small
>> fraction of a second (I hope that the dust on the blade won't be an
>> issue). :) I've seen you post in another "forum" so I believe you are
>> up to the calculation. I do not have engineering background to back me
>> up, I'm just thinking it through with you and everyone else who is
>> reading. Evidently, you'll need to generate the equivalent of an equal
>> and opposite amount of energy. This means, I think, that you only get
>> the benefit of a "projection" (dot product) and not all of the force you
>> can apply to the side of the blade. My reasoning could definitely be
>> off, maybe a physicist or engineer could help out?
>
> Disk brakes work by friction. The energy comes off as heat. Apply F to
> the brake, k * F is the braking force where k is the coefficient of
> friction.
>
> Back of the envelope it looks like the Lincoln brake at Lincoln pressure
> can stop it in about 1/3 revolution. Don't know how much higher
> pressure that caliper can take--at 2x the pressure might be able to do
> it in 1/6 revolution, which puts it in Sawstop territory.
>
Interesting. Thank you. I'm not sure about your "imposter"..
Bill
On Oct 17, 5:38=A0pm, Larry Jaques <[email protected]>
wrote:
> On Sun, 17 Oct 2010 15:01:07 -0400, [email protected] wrote:
> >On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
> ><[email protected]> wrote:
> >>I was comparing efficiencies for a given number of square inches of
> >>friction material, as noted further on in my last post. =A0If you want
> >>to cheat, go ahead, but...
>
> >You didn't state you were comparing area of friction material, sonI'm
> >not cheating. Drum brakes have more friction material for the same
> >brake diameter.
>
> I did, and I quote: =A0 "For a given poundage and square inch of pad,
> they're better than drums."
>
> >And you are wrong on one other point. Disc brakes are generally
> >accepted as being HEAVIER than drum brakes of the same size, due to
> >the requirements of both the caliper and caliper frame vs stamped
> >backplate of a drum brake. The drum itself, compared to the rotor, can
> >go from being a virtual wash to the rotors being slightly lighter.
>
> I'm used to full-sized vehicles, and the drums outweigh the entire
> rest of the front suspension. =A0YMMV.
>
> >>True, and it takes, what, about one quarter -second- of applied
> >>braking to warm them up? =A0Gimme a break!
>
> >Can take a lot longer than that. Depending on the pad material, of
> >course.
>
> Moving into racing parts, sure. =A0And they're lighter still. =A0I don't
> know about you, but most people back out of their driveway and hit a
> couple of stopsigns before they hit the freeway for a high-speed
> braking situation. =A0Those 90%+ have warm brakes before they get up to
> speed. =A0I just don't see your point at all unless it's semi-metallic
> pads, and they take a helluva lot more force to stop, too. Whole
> nother ball of worms and NOT standard equipment.
>
> --
> Know how to listen, and you will
> profit even from those who talk badly.
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 -- Plutarch
All you need to do is look at the history of the disc brake.
Lightweight, high-speed stopping power, reliable, operable in wet
conditions... IOW...aircraft.
On the back-end of a competition car, inboard disc brakes are often
used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
competition drive systems, the discs are sometimes even found inboard,
at the front-end.
There simply isn't one single reason NOT to have disc brakes.
On Sun, 17 Oct 2010 15:01:07 -0400, [email protected] wrote:
>On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
><[email protected]> wrote:
>>I was comparing efficiencies for a given number of square inches of
>>friction material, as noted further on in my last post. If you want
>>to cheat, go ahead, but...
>
>You didn't state you were comparing area of friction material, sonI'm
>not cheating. Drum brakes have more friction material for the same
>brake diameter.
I did, and I quote: "For a given poundage and square inch of pad,
they're better than drums."
>And you are wrong on one other point. Disc brakes are generally
>accepted as being HEAVIER than drum brakes of the same size, due to
>the requirements of both the caliper and caliper frame vs stamped
>backplate of a drum brake. The drum itself, compared to the rotor, can
>go from being a virtual wash to the rotors being slightly lighter.
I'm used to full-sized vehicles, and the drums outweigh the entire
rest of the front suspension. YMMV.
>>True, and it takes, what, about one quarter -second- of applied
>>braking to warm them up? Gimme a break!
>
>Can take a lot longer than that. Depending on the pad material, of
>course.
Moving into racing parts, sure. And they're lighter still. I don't
know about you, but most people back out of their driveway and hit a
couple of stopsigns before they hit the freeway for a high-speed
braking situation. Those 90%+ have warm brakes before they get up to
speed. I just don't see your point at all unless it's semi-metallic
pads, and they take a helluva lot more force to stop, too. Whole
nother ball of worms and NOT standard equipment.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
Rust on the back disks from lack of heavy usage.
I doubt it would be oak rust, though.
"Robatoy" <[email protected]> wrote in message
news:058dd0c2-22db-4edf-8102-55bf22a97265@d17g2000yqm.googlegroups.com...
All you need to do is look at the history of the disc brake.
Lightweight, high-speed stopping power, reliable, operable in wet
conditions... IOW...aircraft.
On the back-end of a competition car, inboard disc brakes are often
used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
competition drive systems, the discs are sometimes even found inboard,
at the front-end.
There simply isn't one single reason NOT to have disc brakes.
On Tue, 19 Oct 2010 12:06:49 -0700 (PDT), Robatoy
<[email protected]> wrote:
>On Oct 19, 1:02Â pm, [email protected] wrote:
>
>
>>
>> So for the same pedal effort (or boosted pressure with power brakes)
>> the drum brake WILL provide more stopping power. That cannot be
>> argued.
>> Period.
>
>I love the way you keep narrowing down the parameters of your
>argument.
>Now we have to apply the same foot-pressure!
>
>But you failed to address the opening act of my position, and that is
>that either system can lock up a wheel completely and do so quite
>easily.
Except I have owned several vehicles that could NOT lock the front
brakes with disc brakes and factory pads. The rear drum brakes WOULD
lock - so they had rear only anti-lock brakes, which flies straight in
the face of your arguement.
The vehicles in question were 1989 and 1990 long body Ford Aerostars
with 3 liter engines and automatic transmission.
When the brake pads were replaced with carbon metallic high
performance pads I could FINALLY lock the front brakes on dry
pavement.
>After that zero rotation has been reached, it doesn't matter
>one bit what is holding that wheel stationary, the tire/road is now
>the friction contact patch.... unless we want to modulate the braking
>action rapidly and accurately via an ABS
Locking the brakes and sliding the wheel is the easy part.(and where
drum brakes excell) But real world braking generally consists of
slowing the vehicle down to a gentle stop without sliding the wheels
and flat-siding the tires. THIS is what builds up heat in the brakes -
which causes drum brakes to loose their effectiveness, and is where
disc brakes have the overwhelming advantage.
> (which was developed by
>Dunlop for aircraft applications) system and good luck doing that with
>drum brakes. (I am not saying that has never been done, cheapos do
>drums on the back-wheels), but it isn't the norm on anything with some
>level of performance, and for very good reasons.)
>But you go ahead and promote your one-stop drum philosophy, I'll stick
>to stuff that works.
>All YOU have to do is remember that every time you use your brakes,
>your life is your foot's hands.
>
>Oh.. and I'm done with this discussion.
Good
And you don't listen well - you just like to argue. Like I said - I
NEVER stated drum brakes were BETTER than discs for automotive use. I
just refuted your statement that disc brakes were more effective for
the application being originally discussed - which was a convenience
brake for a table saw............ and lighter etc.
>
>>
>> And except for some of the more esoteric high priced (automotive)
>> brakes like (possibly) the Brembo, the combination of caliper, rotor,
>> and frame weights of a disc brake will outweigh all but the beafiest
>> drum brake implementation of the same diameter (by a significant
>> amount).
>
> .......and what the hell does that have anything to do with the price
>of fish?
Somebody wrote:
> There AREelectric motors that DO have a drum brake on the fan
> (opposite the drive ) end of the motor. They COULD be used on a
> table
> saw.
----------------------------------
Not in the 20 years I sold brake motors.
Dings was the primary supplier of disk brakes to most of the motor
manufacturers.
Lew
On Oct 19, 11:31=A0pm, [email protected] wrote:
>
> The vehicles in question were 1989 and 1990 long body Ford Aerostars
> with 3 liter engines and automatic transmission.
Ha! Now I KNOW you were just pulling my leg!
On Tue, 19 Oct 2010 21:55:45 -0400, "Josepi" <[email protected]>
wrote:
>OK, let's put drum brakes on the arbor of the motor!
>
>Somebody tell me how we are going to implement drum brakes on a T/S?
>
>
>
>"Steve Turner" <[email protected]> wrote in message
>news:[email protected]...
>Is this horse dead YET? Please tell me it's dead...
There AREelectric motors that DO have a drum brake on the fan
(opposite the drive ) end of the motor. They COULD be used on a table
saw.
Dupar is a name that comes to mind.
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
Not in the 20 years I sold brake motors.
Dings was the primary supplier of disk brakes to most of the motor
manufacturers.
Lew
Somebody wrote:
> There AREelectric motors that DO have a drum brake on the fan
> (opposite the drive ) end of the motor. They COULD be used on a
> table
> saw.
----------------------------------
On Sun, 17 Oct 2010 14:38:12 -0700, Larry Jaques
<[email protected]> wrote:
>On Sun, 17 Oct 2010 15:01:07 -0400, [email protected] wrote:
>
>>On Sun, 17 Oct 2010 09:40:33 -0700, Larry Jaques
>><[email protected]> wrote:
>>>I was comparing efficiencies for a given number of square inches of
>>>friction material, as noted further on in my last post. If you want
>>>to cheat, go ahead, but...
>>
>>You didn't state you were comparing area of friction material, sonI'm
>>not cheating. Drum brakes have more friction material for the same
>>brake diameter.
>
>I did, and I quote: "For a given poundage and square inch of pad,
>they're better than drums."
>
>
>>And you are wrong on one other point. Disc brakes are generally
>>accepted as being HEAVIER than drum brakes of the same size, due to
>>the requirements of both the caliper and caliper frame vs stamped
>>backplate of a drum brake. The drum itself, compared to the rotor, can
>>go from being a virtual wash to the rotors being slightly lighter.
>
>I'm used to full-sized vehicles, and the drums outweigh the entire
>rest of the front suspension. YMMV.
>
Even on full-sized Mopars of the seventies, the disc brake assembly
outweighed the drum brake on the same car by something around 2 lbs
>
>
>>>True, and it takes, what, about one quarter -second- of applied
>>>braking to warm them up? Gimme a break!
>>
>>Can take a lot longer than that. Depending on the pad material, of
>>course.
>
>Moving into racing parts, sure. And they're lighter still. I don't
>know about you, but most people back out of their driveway and hit a
>couple of stopsigns before they hit the freeway for a high-speed
>braking situation. Those 90%+ have warm brakes before they get up to
>speed. I just don't see your point at all unless it's semi-metallic
>pads, and they take a helluva lot more force to stop, too. Whole
>nother ball of worms and NOT standard equipment.
Depends on the vehicle. LOTS of cars come/came with semi-metallic
brake pads as standard equipment.
Ceramics are even worse - but not nearly as common as standard
equipment.
I like the new Hybrid pads, with 2 (at least) different friction
materials. One works good cold, and one works good hot, while both
work pretty well in between. Pricey little buggers though - over $235
for the front set on my PT Cruiser. They DO stop well. NO ABS on this
car, and I can lock all 4 wheels at will on dry pavement (rear drums,
front discs)
I have Kevlars on the front of the wife's Mystique, and with the ABS
disabled I can lock that one up too. Could NOT with the factory pads -
4 wheel discs on that puppy. They are good cold, fantastic under
normal conditions, and much better than average when well heated up.
You must be too young to remeber driving on the highway and wondering if the
brakes will stop you the second time with drum brakes. How many brake
hydraulic systems have you exploded from stepping too hard with both feet?
Besides, what else would we argue about?
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
Disc brakes, drum brakes, who gives a good fiddly fuck?
Lew
On 10/13/2010 02:32 PM, J. Clarke wrote:
> In article<[email protected]>,
> [email protected] says...
>>
>> On 10/13/10 9:43 AM, J. Clarke wrote:
>>> In article<[email protected]>, [email protected] says...
>>>>
>>>> J. Clarke wrote:
>>>>> In article<[email protected]>, [email protected] says...
>>>>>>
>>>>>> J. Clarke wrote:
>>>>>>> In article<[email protected]>,
>>>>>>> [email protected] says...
>>>>>>>>
>>>>>>>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill<[email protected]> wrote:
>>>>>>>>
>>>>>>>>> J. Clarke wrote:
>>>>>>>>>> In article<[email protected]>, [email protected] says...
>>>>>>>>>>>
>>>>>>>>>>> I would think that an emergency stop mechanism would be a whole different
>>>>>>>>>>> magnitude than a scheduled, everyday, stop.
>>>>>>>>>>>
>>>>>>>>>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>>>>>>>>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>>>>>>>>>>> would be OK too. These two situations would require different tactics.
>>>>>>>>>>>
>>>>>>>>>>> A dynamic electronic brake could vary the intensity for the two different
>>>>>>>>>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>>>>>>>>>>> wouldn't last long in everyday usage and would need to be adjusted and/or
>>>>>>>>>>> replaced frequently.
>>>>>>>>>>
>>>>>>>>>> So how much power do you have to put into that electronic brake to stop
>>>>>>>>>> the blade as fast as Sawstop's physical block?
>>>>>>>>>>
>>>>>>>>>> And why would a caliper not last long? A set of brake pads on a car
>>>>>>>>>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>>>>>>>>>> a lot more of a workout that they would stopping a little bitty saw
>>>>>>>>>> blade that masses less than 1/1000 as much.
>>>>>>>>>
>>>>>>>>> The physics on that seem interesting. A little like stopping a speeding
>>>>>>>>> bullet on a dime--it challenges my imagination. Probably not quite as
>>>>>>>>> difficult as stopping a lightning bolt, but I wouldn't want to try that
>>>>>>>>> either.
>>>>>>>>>
>>>>>>>>> Bill
>>>>>>>> No way a caliper could stop the blade in even 4X the time the
>>>>>>>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>>>>>>>> the blade would be quite problematic - with dust decreasing the
>>>>>>>> stopping efficiency by a very large margin.
>>>>>>>
>>>>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>>>>> my '76 Lincoln might surprise you.
>>>>>>>
>>>>>>
>>>>>> When it snapped (seriously)? I'm not an engineer, so I don't know for
>>>>>> sure. I just wouldn't be surprised. Maybe someone else can opine.
>>>>>
>>>>> Why would something that can stop a 4000 pound car "snap" when called on
>>>>> to stop a 3 pound saw blade?
>>>>
>>>> "Pyrotechnics" rather than a master cylinder with brake fluid?
>>>
>>> To stop the saw in a fraction of a revolution, you need rapid
>>> application. A pyro will build pressure rapidly.
>>
>> I didn't think we were talking about an emergency stop.
>> AFAIK, we're discussing a convenience stop which, in my opinion, would
>> be satisfactorily done in a couple seconds, not milliseconds.
>
> Well, geez, for that a bicycle brake will work fine.
Another reality check for all the people taking this thread off into the wild blue yonder is
the issue of getting the blade onto the arbor in the presence of calipers that grip either
side of the blade. My interest (and Mike's as well, I think) in using a bicycle brake was
simply a matter of "how can I retrofit my existing table saw with a simple convenience
brake?" I think the wide-opening jaws of a bicycle brake (maybe along with some kind of
front-side cable disconnect to allow the calipers to drop out of the way) would allow enough
clearance to get the blade on the arbor without too much trouble. This heavy-duty
automotive caliber Saw-Stop alternative that everybody else is talking about would also have
to provide a similar mechanism, which would of course add to the complexity.
--
So will there ever be a day, throughout the rest of my life, that I
won't encounter in the written word a case of somebody not understanding
the difference between the meanings of the words "to" and "too"?
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/2010 7:52 AM, Mike Marlow wrote:
> Steve Turner wrote:
>
>>
>> Another reality check for all the people taking this thread off into
>> the wild blue yonder is the issue of getting the blade onto the arbor
>> in the presence of calipers that grip either side of the blade. My
>> interest (and Mike's as well, I think) in using a bicycle brake was
>> simply a matter of "how can I retrofit my existing table saw with a
>> simple convenience brake?" I think the wide-opening jaws of a
>> bicycle brake (maybe along with some kind of front-side cable
>> disconnect to allow the calipers to drop out of the way) would allow
>> enough clearance to get the blade on the arbor without too much
>> trouble. This heavy-duty automotive caliber Saw-Stop alternative
>> that everybody else is talking about would also have to provide a
>> similar mechanism, which would of course add to the complexity.
>
> It would be quite easy to mount the caliper on a pivoting mount that would
> allow it to swing out of the way for changing blades.
Yes, probably; most automobiles with disc brakes that I've worked on use a
similar pivot mechanism. But then there's the matter of pivoting the caliper
from above the table. I can't imagine there'd be enough room through the
insert opening on the table-top to actuate such a mechanism, so you'd probably
need some kind of easy-access lever or opening in the cabinet that would allow
you to get to it.
--
"Our beer goes through thousands of quality Czechs every day."
(From a Shiner Bock billboard I saw in Austin some years ago)
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/10 6:39 AM, Steve Turner wrote:
> Another reality check for all the people taking this thread off into the
> wild blue yonder is the issue of getting the blade onto the arbor in the
> presence of calipers that grip either side of the blade. My interest
> (and Mike's as well, I think) in using a bicycle brake was simply a
> matter of "how can I retrofit my existing table saw with a simple
> convenience brake?" I think the wide-opening jaws of a bicycle brake
> (maybe along with some kind of front-side cable disconnect to allow the
> calipers to drop out of the way) would allow enough clearance to get the
> blade on the arbor without too much trouble.
Heck, I think if it was mounted closer to the arbor than the edge, one
pad on the arbor side of the blade would be sufficient for a convenience
slow/stop.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/2010 12:15 PM, -MIKE- wrote:
> On 10/14/10 6:39 AM, Steve Turner wrote:
>> Another reality check for all the people taking this thread off into the
>> wild blue yonder is the issue of getting the blade onto the arbor in the
>> presence of calipers that grip either side of the blade. My interest
>> (and Mike's as well, I think) in using a bicycle brake was simply a
>> matter of "how can I retrofit my existing table saw with a simple
>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>> (maybe along with some kind of front-side cable disconnect to allow the
>> calipers to drop out of the way) would allow enough clearance to get the
>> blade on the arbor without too much trouble.
>
> Heck, I think if it was mounted closer to the arbor than the edge, one
> pad on the arbor side of the blade would be sufficient for a convenience
> slow/stop.
Maybe so, but that sounds like asking for trouble!
Bill
On 10/14/2010 11:15 AM, -MIKE- wrote:
> On 10/14/10 6:39 AM, Steve Turner wrote:
>> Another reality check for all the people taking this thread off into the
>> wild blue yonder is the issue of getting the blade onto the arbor in the
>> presence of calipers that grip either side of the blade. My interest
>> (and Mike's as well, I think) in using a bicycle brake was simply a
>> matter of "how can I retrofit my existing table saw with a simple
>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>> (maybe along with some kind of front-side cable disconnect to allow the
>> calipers to drop out of the way) would allow enough clearance to get the
>> blade on the arbor without too much trouble.
>
> Heck, I think if it was mounted closer to the arbor than the edge, one pad on
> the arbor side of the blade would be sufficient for a convenience slow/stop.
That very well could be true, and you could also use such a brake with dado
blades of any thickness... Interesting observation there Mike; I'm gonna have
to go do some peeking inside my Unisaw to see what the possibilities are. :-)
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/10 11:17 AM, Bill wrote:
> On 10/14/2010 12:15 PM, -MIKE- wrote:
>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>> Another reality check for all the people taking this thread off into the
>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>> presence of calipers that grip either side of the blade. My interest
>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>> matter of "how can I retrofit my existing table saw with a simple
>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>> (maybe along with some kind of front-side cable disconnect to allow the
>>> calipers to drop out of the way) would allow enough clearance to get the
>>> blade on the arbor without too much trouble.
>>
>> Heck, I think if it was mounted closer to the arbor than the edge, one
>> pad on the arbor side of the blade would be sufficient for a convenience
>> slow/stop.
>
> Maybe so, but that sounds like asking for trouble!
>
> Bill
How? Really. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 11:27 AM, Steve Turner wrote:
> On 10/14/2010 11:15 AM, -MIKE- wrote:
>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>> Another reality check for all the people taking this thread off into the
>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>> presence of calipers that grip either side of the blade. My interest
>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>> matter of "how can I retrofit my existing table saw with a simple
>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>> (maybe along with some kind of front-side cable disconnect to allow the
>>> calipers to drop out of the way) would allow enough clearance to get the
>>> blade on the arbor without too much trouble.
>>
>> Heck, I think if it was mounted closer to the arbor than the edge, one
>> pad on
>> the arbor side of the blade would be sufficient for a convenience
>> slow/stop.
>
> That very well could be true, and you could also use such a brake with
> dado blades of any thickness... Interesting observation there Mike; I'm
> gonna have to go do some peeking inside my Unisaw to see what the
> possibilities are. :-)
>
Good. It's about time that happens to someone *else.*
Let me know what you come up with so I can take credit for it. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/2010 11:47 AM, -MIKE- wrote:
> On 10/14/10 11:27 AM, Steve Turner wrote:
>> On 10/14/2010 11:15 AM, -MIKE- wrote:
>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>> Another reality check for all the people taking this thread off into the
>>>> wild blue yonder is the issue of getting the blade onto the arbor in the
>>>> presence of calipers that grip either side of the blade. My interest
>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>> matter of "how can I retrofit my existing table saw with a simple
>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>> calipers to drop out of the way) would allow enough clearance to get the
>>>> blade on the arbor without too much trouble.
>>>
>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>> pad on
>>> the arbor side of the blade would be sufficient for a convenience
>>> slow/stop.
>>
>> That very well could be true, and you could also use such a brake with
>> dado blades of any thickness... Interesting observation there Mike; I'm
>> gonna have to go do some peeking inside my Unisaw to see what the
>> possibilities are. :-)
>>
>
> Good. It's about time that happens to someone *else.*
> Let me know what you come up with so I can take credit for it. :-)
Well, peek I did, but it seems the opportunities for mounting such a device, on
the Unisaw at least, are virtually nil. There are just too many clearance
problems to overcome. However, it does seem possible that I could mount a thin
disc to the motor pulley (one that's a couple of inches larger in diameter) and
apply caliper pressure to that instead. The calipers would have to be mounted
to a bracket that attaches to the motor housing, but that shouldn't be too hard
to accomplish.
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/2010 12:44 PM, -MIKE- wrote:
> On 10/14/10 11:17 AM, Bill wrote:
>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>> Another reality check for all the people taking this thread off into
>>>> the
>>>> wild blue yonder is the issue of getting the blade onto the arbor in
>>>> the
>>>> presence of calipers that grip either side of the blade. My interest
>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>> matter of "how can I retrofit my existing table saw with a simple
>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>> (maybe along with some kind of front-side cable disconnect to allow the
>>>> calipers to drop out of the way) would allow enough clearance to get
>>>> the
>>>> blade on the arbor without too much trouble.
>>>
>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>> pad on the arbor side of the blade would be sufficient for a convenience
>>> slow/stop.
>>
>> Maybe so, but that sounds like asking for trouble!
>>
>> Bill
>
> How? Really. :-)
>
I'll defer to your wisdom and experience which is surely more vast than
mine. My limited experience and intuition tells me "something is wrong
in that picture"... : )
Bill
On 10/14/10 11:58 AM, Bill wrote:
> On 10/14/2010 12:44 PM, -MIKE- wrote:
>> On 10/14/10 11:17 AM, Bill wrote:
>>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>> Another reality check for all the people taking this thread off into
>>>>> the
>>>>> wild blue yonder is the issue of getting the blade onto the arbor in
>>>>> the
>>>>> presence of calipers that grip either side of the blade. My interest
>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>> (maybe along with some kind of front-side cable disconnect to allow
>>>>> the
>>>>> calipers to drop out of the way) would allow enough clearance to get
>>>>> the
>>>>> blade on the arbor without too much trouble.
>>>>
>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>> pad on the arbor side of the blade would be sufficient for a
>>>> convenience
>>>> slow/stop.
>>>
>>> Maybe so, but that sounds like asking for trouble!
>>>
>>> Bill
>>
>> How? Really. :-)
>>
>
> I'll defer to your wisdom and experience which is surely more vast than
> mine. My limited experience and intuition tells me "something is wrong
> in that picture"... : )
>
> Bill
>
And here I thought usenet for was for sharing ideas and learning from
one another.
How silly of me.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 12:58 PM, Robatoy wrote:
> Any disc or drum of any size will interfere with the raising of the
> blade to the point that the disk brake hits the bottom of the table
> somewhere.
>
> I propose an air bag. Electronically triggered, it throws you
> backwards across the shop and away from the table saw. Punches you
> right in the chest with the option for a double bag for some people
> here in which case the second bag knocks some sense in them. We can
> glue on a boxing glove for that operation...just a 4 oz. one; you want
> it to hurt a little.
> One can mount the boxing glove on an expanding multi-pivot articulated
> parallelogram.
> What a stellar idea.
> I'm talking to investors now.
> They want to call the company ACME.
Beautiful. Wile E. fricken beautiful.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/2010 1:47 PM, -MIKE- wrote:
> On 10/14/10 11:58 AM, Bill wrote:
>> On 10/14/2010 12:44 PM, -MIKE- wrote:
>>> On 10/14/10 11:17 AM, Bill wrote:
>>>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>>> Another reality check for all the people taking this thread off into
>>>>>> the
>>>>>> wild blue yonder is the issue of getting the blade onto the arbor in
>>>>>> the
>>>>>> presence of calipers that grip either side of the blade. My interest
>>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>>> (maybe along with some kind of front-side cable disconnect to allow
>>>>>> the
>>>>>> calipers to drop out of the way) would allow enough clearance to get
>>>>>> the
>>>>>> blade on the arbor without too much trouble.
>>>>>
>>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>>> pad on the arbor side of the blade would be sufficient for a
>>>>> convenience
>>>>> slow/stop.
>>>>
>>>> Maybe so, but that sounds like asking for trouble!
>>>>
>>>> Bill
>>>
>>> How? Really. :-)
>>>
>>
>> I'll defer to your wisdom and experience which is surely more vast than
>> mine. My limited experience and intuition tells me "something is wrong
>> in that picture"... : )
>>
>> Bill
>>
>
> And here I thought usenet for was for sharing ideas and learning from
> one another.
> How silly of me.
The problem with me sharing something about this is that someone might
(conceivably, if they had been drinking, perhaps...) think I know what
I'm talking about. I was just thinking about all of the bicycles I've
seen that had a brake pad on just one side...
It couldn't be any good for the bearings (on the motor on the TS), huh?
Bill
On 10/14/2010 1:47 PM, -MIKE- wrote:
> On 10/14/10 11:58 AM, Bill wrote:
>> On 10/14/2010 12:44 PM, -MIKE- wrote:
>>> On 10/14/10 11:17 AM, Bill wrote:
>>>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>>> Another reality check for all the people taking this thread off into
>>>>>> the
>>>>>> wild blue yonder is the issue of getting the blade onto the arbor in
>>>>>> the
>>>>>> presence of calipers that grip either side of the blade. My interest
>>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>>> (maybe along with some kind of front-side cable disconnect to allow
>>>>>> the
>>>>>> calipers to drop out of the way) would allow enough clearance to get
>>>>>> the
>>>>>> blade on the arbor without too much trouble.
>>>>>
>>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>>> pad on the arbor side of the blade would be sufficient for a
>>>>> convenience
>>>>> slow/stop.
>>>>
>>>> Maybe so, but that sounds like asking for trouble!
>>>>
>>>> Bill
>>>
>>> How? Really. :-)
>>>
>>
>> I'll defer to your wisdom and experience which is surely more vast than
>> mine. My limited experience and intuition tells me "something is wrong
>> in that picture"... : )
>>
>> Bill
>>
>
> And here I thought usenet for was for sharing ideas and learning from
> one another.
> How silly of me.
>
>
I read this on the Internet:
... avoid unnecessary stress on the motor or arbor bearings.
Bill
On 10/14/10 1:09 PM, Bill wrote:
> On 10/14/2010 1:47 PM, -MIKE- wrote:
> The problem with me sharing something about this is that someone might
> (conceivably, if they had been drinking, perhaps...) think I know what
> I'm talking about. I was just thinking about all of the bicycles I've
> seen that had a brake pad on just one side...
>
That is a completely irrelevant comparison.
Look at the forces involved.
A bicycle brake is dealing with what I might speculate to be 1000x the
force.
200lbs at 25+mph is a lot momentum and those little pads do quite a good
job at it.
A coasting 10" saw blade along with whatever mass is added to it by the
arbor assembly is stopped in a couple seconds by light pressure applied
to the side of the blade with a 1cc section of mdf.
I do it all the time. I could probably use my finger.
Try stopping a bike going down hill with that little piece of mdf
pressed lightly against the wheel. Won't happen. :-)
> It couldn't be any good for the bearings (on the motor on the TS), huh?
>
> Bill
The arbor on my Delta is a pretty massive item. In another post, I
stated that I would put the pad closer to the arbor, *just in case.*
However, the arbor bearings that couldn't handle the little amount of
pressure it would take to slow down a coasting saw blade wouldn't last
very long on a table saw in its normal operation.
Grinding wheel arbors and extensions don't seem to be affected by forces
much, much greater than what I've considering.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/2010 1:11 PM, Bill wrote:
> On 10/14/2010 1:47 PM, -MIKE- wrote:
>> On 10/14/10 11:58 AM, Bill wrote:
>>> On 10/14/2010 12:44 PM, -MIKE- wrote:
>>>> On 10/14/10 11:17 AM, Bill wrote:
>>>>> On 10/14/2010 12:15 PM, -MIKE- wrote:
>>>>>> On 10/14/10 6:39 AM, Steve Turner wrote:
>>>>>>> Another reality check for all the people taking this thread off into
>>>>>>> the
>>>>>>> wild blue yonder is the issue of getting the blade onto the arbor in
>>>>>>> the
>>>>>>> presence of calipers that grip either side of the blade. My interest
>>>>>>> (and Mike's as well, I think) in using a bicycle brake was simply a
>>>>>>> matter of "how can I retrofit my existing table saw with a simple
>>>>>>> convenience brake?" I think the wide-opening jaws of a bicycle brake
>>>>>>> (maybe along with some kind of front-side cable disconnect to allow
>>>>>>> the
>>>>>>> calipers to drop out of the way) would allow enough clearance to get
>>>>>>> the
>>>>>>> blade on the arbor without too much trouble.
>>>>>>
>>>>>> Heck, I think if it was mounted closer to the arbor than the edge, one
>>>>>> pad on the arbor side of the blade would be sufficient for a
>>>>>> convenience
>>>>>> slow/stop.
>>>>>
>>>>> Maybe so, but that sounds like asking for trouble!
>>>>>
>>>>> Bill
>>>>
>>>> How? Really. :-)
>>>>
>>>
>>> I'll defer to your wisdom and experience which is surely more vast than
>>> mine. My limited experience and intuition tells me "something is wrong
>>> in that picture"... : )
>>>
>>> Bill
>>>
>>
>> And here I thought usenet for was for sharing ideas and learning from
>> one another.
>> How silly of me.
>>
>>
> I read this on the Internet:
> ... avoid unnecessary stress on the motor or arbor bearings.
>
> Bill
Now you're reading this on the internet, which also makes it true:
The force applied to the blade near the arbor by a small bicycle brake caliper
is going to be far less stressful on the arbor bearings than some gnarly nasty
piece of wood that's twisting into the blade at the outer perimeter while
you're trying to cut it. When you have a piece of wood that's binding on the
blade and you cut power to the motor, think of how little time it actually
takes for the blade to stop. What, a second or two maybe? That's all I would
be asking for in a convenience brake; to stop the blade within a second or two,
rather than the 10 or 15 seconds (or longer on some saws) it takes for the
blade to stop by itself, and it's not going to take that much pressure to get
it done. And as you've also read on the internet, it's pretty common practice
for people to stop the blade by shoving a piece of wood up against it from the
side; I'd imagine that would also put more stress on the arbor bearings than an
inboard brake caliper.
--
"Even if your wife is happy but you're unhappy, you're still happier
than you'd be if you were happy and your wife was unhappy." - Red Green
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
This was exactly my point.
The other thing, and unfair to the 17 teeth is OK defence is that the
SawStop pulls the blade away and down. It appears to be grabbed on the back
side of the blade and the inertia pulls the balde back and under the table
effectively removing the blade from the finger area. I doubt you would want
to do this everytime in a **NON**emergency stop. My guess is arbor bending
would set in after a few dozen of them.
Watch the videos (most have). This is no gentle stop for an armature and saw
blade of that intertia.
So the retort to the 17 teeth big damage people is still "How fast do you
push your finger?"
OTOH: Pushing the stock, slipping off, and back handing a running blade can
be different speeds.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
I've seen a hotdog demonstration in which they *did* push the dog, on
top of a piece of wood, into the blade as quick as the blade with
receive it. It was much faster than anyone with any sense would advance
any stock into a table saw. The dog had the tiniest little sliver of
"skin" taken off. Had it been a finger, it would surely have bled a drop
or two. But I've done much worse to my finger when a file slipped or I
got a splinter.
--
17 teeth?
How fast can you push your finger?
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
That may be true, but they still don't do any harm.
> Sawstop stops the blade in 1/200 of a second, according to their Web
> site. At 3450 RPM that means the blade stops in .29 revolution, which
> with a 60 tooth blade means that 17 teeth have had a shot at your
> finger.
>
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
WW wrote the following:
> "HeyBub" <[email protected]> wrote in message
> news:[email protected]...
>
>> Found this article...
>>
>> "Single-phase induction motors drive many arbor-mounted cutting tools in
>> the home workshop. Stationary grinders, table and radial arm circular saws
>> frequently turn abrasive or cutting disks that are directly mounted on the
>> motor's spindle. These disks have large inertial moments that allow them
>> to free wheel for a long time after the power is turned off. A lengthy
>> coast to complete stop often amounts to a major inconvenience."
>>
>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>
>>
>> Great ... I may rig up my table saw this way. Would be safer with a brake.
>> WW
If I need to stop a spinning table saw blade in a hurry to change or
reset something, I find that a scrap piece of lumber makes a great blade
brake. Turn the saw off and slide the scrap up to the still spinning
blade. Blade stops in a couple of seconds. No extra parts needed.
--
Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @
On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>>
>> >J. Clarke wrote:
>> >> In article<[email protected]>, [email protected] says...
>> >>>
>> >>> I would think that an emergency stop mechanism would be a whole different
>> >>> magnitude than a scheduled, everyday, stop.
>> >>>
>> >>> For a finger saver an emergency stop mechanism would have to stop the blade
>> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>> >>> would be OK too. These two situations would require different tactics.
>> >>>
>> >>> A dynamic electronic brake could vary the intensity for the two different
>> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
>> >>> replaced frequently.
>> >>
>> >> So how much power do you have to put into that electronic brake to stop
>> >> the blade as fast as Sawstop's physical block?
>> >>
>> >> And why would a caliper not last long? A set of brake pads on a car
>> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> >> a lot more of a workout that they would stopping a little bitty saw
>> >> blade that masses less than 1/1000 as much.
>> >
>> >The physics on that seem interesting. A little like stopping a speeding
>> >bullet on a dime--it challenges my imagination. Probably not quite as
>> >difficult as stopping a lightning bolt, but I wouldn't want to try that
>> >either.
>> >
>> >Bill
>> No way a caliper could stop the blade in even 4X the time the
>> saw-stop does. And keeping dust out of the gap between tha "pad" and
>> the blade would be quite problematic - with dust decreasing the
>> stopping efficiency by a very large margin.
>
>I suspect that a small pyrotechnic pressurizing one of the calipers off
>my '76 Lincoln might surprise you.
>
But would also be totally impractical on a 10" saw.
[email protected] wrote:
> Either way, electrical application is the simplest, cheapest
> alternative (compared to hydraulic, mechanical, pneumatic, or
> percussive application) - and if you are going to use electical or
> electronic controls anyway, why not use electrical braking all the
> way?
>
> That's my point. Nobody else, so far, has addressed how they would
> control the application of this "convenience brake", however
> implemented. My pushbutton solution was rejected out of hand - but how
> would any of the other suggested possibilities be implemented???
>
Well, I have agreed (but you may have missed), that the caliper may not be
the most elegant solution. As for this thread and the discussions about
calipers for this application - mostly idle mental masterbation in my
opinion. Sometimes dabbling with an idea doesn't need to be more than just
that.
--
-Mike-
[email protected]
OK, so we go with a caliper brake of some kind...Looks simple enough on the
surface.
What would operate it? Would it be electrically controlled? Automatic,
Handjob (manual)?
It would have to mounted to the mechanism that tilts the blade so it goes
with it.
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
In my case, it's because I can understand and implement mechanical devices;
electrical, not so much. If somebody were to implement and test and
guarantee
an electrical braking system that could be retrofitted to my Unisaw I would
certainly be interested.
I have every confidence that I can implement a mechanical solution on my
Unisaw, and believe me, the naysayer attitude of a certain few (ahem) has
just
about ticked me off enough to follow through with it. My only problem is
carving out the time to get it done; I have precious little of that these
days.
In article <[email protected]>,
<[email protected]> wrote:
> That's my point. Nobody else, so far, has addressed how they would
> control the application of this "convenience brake", however
> implemented. My pushbutton solution was rejected out of hand - but how
> would any of the other suggested possibilities be implemented???
OK, here goes:
Pair of AC solenoids, one each side of the blade holding a brake pad away
from the blade, paralleled with feed to motor. When motor is powered
brakes are off, when motor switched off solenoids de-energise and springs
press pads against sides of blade. This is a "convenience" brake, no need
for great forces to be applied. Solenoids mounted on a sliding
arrangement, operated by a lever, which allows them to be moved out of the
way for blade changing.
On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
<[email protected]> wrote:
>On 10/14/2010 2:52 PM, [email protected] wrote:
>> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> Larry Jaques wrote:
>>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>>>> <[email protected]> wrote:
>>>
>>>>>
>>>>> As a guy who has done all of his own vehicle maintenance for 40
>>>>> years now, I have to ask what you observed in your experiences, that
>>>>> causes you to make this statement? I don't know if the brake
>>>>> caliper idea is the most elegant solution, but I sure can't see
>>>>> anything in what you are saying that would suggest it is not a
>>>>> workable solution.
>>>>
>>>> Suitable placement of an air nozzle tube to clear the caliper frame
>>>> every hour or so would go far into making this device work for more
>>>> than an hour. You'd have to keep the sawdust from piercing the seals
>>>> and/or building up on the frame
>>>
>>> Not at all Larry, if you consider what a normal brake caliper in an
>>> automobile is subject to. In comparison, the environment inside a table saw
>>> would be a walk in the part of a caliper.
>>
>>
>> You get a splinter of oak thrown at a rubber caliper boot at 18000
>> feet per minute (almost 205MPH) a few times and expect the boot to
>> survive?. For the brake to see the same rotational RPM on a car with
>> 24" diameter tires (pretty standard today) you would need to drive
>> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
>>
>> A 10" saw runs closer to 5200 RPM - so 370 MPH.
>
>Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
>would be even more impossible to stop.
>
No, I said nothing of the sort. I didn't even say anything about it
being hard to stop. I was comaring the speed at which particals might
possibly hit the boot on the lincoln caliper some dufus was talking
about mounting to the table saw to stop the blade, The speed at which
a sliver could be flung at that boot from a typical table saw blade
would require the above mentioned speeds with the caliper on a car -
assuming the bit was picked up from the road or thrown from the
circumference of the tire.
>> Also, the caliper is actually pretty well protected mounted as it is
>> virtually inside the wheel - with the caliper boot protected between
>> the pad and tha caliper frame, and usually behind a splash shield as
>> well.
>>
>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>> onto every surface of the caliper.
>
>Geez Chicken Little, how many mountains are you going to make out of molehills
>on this topic? Just about every point you've tried to make has had the air of
>doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
Nobody said it was difficult. Just saying the brake from the old
lincoln is NOT going to be anywhere close to an effective solution.
So many guys on the Wreck just make things WAY too complicated.
You want a convenience brake on an AC table saw? DC injection braking
is as simple as it gets and can be done by a reasonably adept
scrounger for less than $25 in less than an hour, with NO
modifications to the physical part of the saw. Just grabbing a few
parts out of my scrap bin I could have it working on a saw in less
than half an hour with no cash outlay at all. Not fully automated -
but hit the stop button or turn off the power and press a pushbutton
untill the blade stops (about 2 seconds) using nothing more than an
old PC power supply and a pushbutton switch. To make it a littlemore
foolproof the power switch would need to be replaces with a SPDT or
DPDT switch or augmented by a relay to prevent injecting the DC while
the AC was still connected.
Larry Jaques wrote:
> On Sat, 16 Oct 2010 21:29:05 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> Larry Jaques wrote:
>>
>>>
>>> I heartily disagree. The only solid ever thrown up at a brake
>>> caliper in any quantity is water, and that runs right off. Sawdust
>>> would tend to stick, especially in the inverted configuration it
>>> would have on a table saw. 'Twould be especially bad with folks who
>>> "do Jummywood."
>>>
>>> Go ahead and prove me wrong, Mike. Mount one and see. I double dare
>>> ya!
>>
>> I'm a sucker for a dare. Damnit... I agree the sawdust would
>> stick, but I don't think that would be a real problem. It would be
>> worn off the braking surface rather easily.
>
> Just in time for a sawdust fire! Oops.
You arse - now you're changing the direction of this thread. We'll have to
labor through fire hazards, fire extinuishers, and smoke detectors now....
--
-Mike-
[email protected]
On Fri, 15 Oct 2010 21:57:44 -0400, "Josepi" <[email protected]>
wrote:
>I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
>actually tilt? Has anybody actually seen the mechanism under the table?
>
>What happens when the sensitive moisture sensor is full of titanic acid oak
>sawdust?
>
>
Yes, it CAN tilt and cut a 45 degree cut. And if you cut damp wood, or
let sawdust build up it WILL false trigger - and that gets expensive.
Have one in the woodworking club shop.
I have seen the mechanism (about 3 years ago when they first got it
and it was triggered and needed the shoe replaced)
see:
http://www.sawdustonthefloor.com/wp-content/uploads/2009/08/Cartridge-Blade-Schematic-for-Saw-Stop.jpg
http://www.aetherczar.com/wp-content/uploads/SawStop-6813983-Fig2.jpg
It is mounted to the yoke assembly, behind the blade, and when it jams
into the blade the blade is pulled down into the table by the blade
inertia (basically it is disconnected from the depth adjustment when
the shoe fires, and the blade inertia sinks the blade)
>
>"J. Clarke" <[email protected]> wrote in message
>news:[email protected]...
>The same place the Sawstop mechanism goes.
>
>
>In article <[email protected]>, [email protected] says...
>
>> Me think we will wait until somebody shows a design drawing of where the
>> caliper goes when the saw blade tips at a 45 degree cut.
>
>
If you consider pushing an oak stick into the side of a carbide toothed
blade turning at 4500 PM as safe as pressing a pushbutton on the side of the
table saw you should never have children.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
If you consider shoving a pushstick into the side of a saw blade to be
dangerous you should never, ever have sex.
In article <twZto.89$s%[email protected]>, [email protected] says...
>
> I believe there would be a definite danger factor difference parameter in
> that one.
>
> Usually convenient though.
>
>
>
>
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
>
> But if I have to push a button to stop the blade I may as well just
> shove a pushstick into the side of it.
In article <[email protected]>,
[email protected] says...
>
> On Thu, 14 Oct 2010 16:22:22 -0500, Steve Turner
> <[email protected]> wrote:
>
> >On 10/14/2010 2:52 PM, [email protected] wrote:
> >> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
> >> <[email protected]> wrote:
> >>
> >>> Larry Jaques wrote:
> >>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
> >>>> <[email protected]> wrote:
> >>>
> >>>>>
> >>>>> As a guy who has done all of his own vehicle maintenance for 40
> >>>>> years now, I have to ask what you observed in your experiences, that
> >>>>> causes you to make this statement? I don't know if the brake
> >>>>> caliper idea is the most elegant solution, but I sure can't see
> >>>>> anything in what you are saying that would suggest it is not a
> >>>>> workable solution.
> >>>>
> >>>> Suitable placement of an air nozzle tube to clear the caliper frame
> >>>> every hour or so would go far into making this device work for more
> >>>> than an hour. You'd have to keep the sawdust from piercing the seals
> >>>> and/or building up on the frame
> >>>
> >>> Not at all Larry, if you consider what a normal brake caliper in an
> >>> automobile is subject to. In comparison, the environment inside a table saw
> >>> would be a walk in the part of a caliper.
> >>
> >>
> >> You get a splinter of oak thrown at a rubber caliper boot at 18000
> >> feet per minute (almost 205MPH) a few times and expect the boot to
> >> survive?. For the brake to see the same rotational RPM on a car with
> >> 24" diameter tires (pretty standard today) you would need to drive
> >> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
> >>
> >> A 10" saw runs closer to 5200 RPM - so 370 MPH.
> >
> >Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
> >would be even more impossible to stop.
> >
>
> No, I said nothing of the sort. I didn't even say anything about it
> being hard to stop. I was comaring the speed at which particals might
> possibly hit the boot on the lincoln caliper some dufus was talking
> about mounting to the table saw to stop the blade, The speed at which
> a sliver could be flung at that boot from a typical table saw blade
> would require the above mentioned speeds with the caliper on a car -
> assuming the bit was picked up from the road or thrown from the
> circumference of the tire.
> >> Also, the caliper is actually pretty well protected mounted as it is
> >> virtually inside the wheel - with the caliper boot protected between
> >> the pad and tha caliper frame, and usually behind a splash shield as
> >> well.
> >>
> >> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> >> onto every surface of the caliper.
> >
> >Geez Chicken Little, how many mountains are you going to make out of molehills
> >on this topic? Just about every point you've tried to make has had the air of
> >doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
>
> Nobody said it was difficult. Just saying the brake from the old
> lincoln is NOT going to be anywhere close to an effective solution.
> So many guys on the Wreck just make things WAY too complicated.
>
> You want a convenience brake on an AC table saw? DC injection braking
> is as simple as it gets and can be done by a reasonably adept
> scrounger for less than $25 in less than an hour, with NO
> modifications to the physical part of the saw. Just grabbing a few
> parts out of my scrap bin I could have it working on a saw in less
> than half an hour with no cash outlay at all. Not fully automated -
> but hit the stop button or turn off the power and press a pushbutton
> untill the blade stops (about 2 seconds) using nothing more than an
> old PC power supply and a pushbutton switch. To make it a littlemore
> foolproof the power switch would need to be replaces with a SPDT or
> DPDT switch or augmented by a relay to prevent injecting the DC while
> the AC was still connected.
But if I have to push a button to stop the blade I may as well just
shove a pushstick into the side of it.
In article <twZto.89$s%[email protected]>, [email protected] says...
>
> I believe there would be a definite danger factor difference parameter in
> that one.
>
> Usually convenient though.
If you consider shoving a pushstick into the side of a saw blade to be
dangerous you should never, ever have sex.
>
>
>
>
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
>
> But if I have to push a button to stop the blade I may as well just
> shove a pushstick into the side of it.
In article <[email protected]>, [email protected] says...
>
> If you consider pushing an oak stick into the side of a carbide toothed
> blade turning at 4500 PM as safe as pressing a pushbutton on the side of the
> table saw you should never have children.
Sex is more dangerous, especially if you're a woman.
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> If you consider shoving a pushstick into the side of a saw blade to be
> dangerous you should never, ever have sex.
>
>
> In article <twZto.89$s%[email protected]>, [email protected] says...
> >
> > I believe there would be a definite danger factor difference parameter in
> > that one.
> >
> > Usually convenient though.
>
> >
> >
> >
> >
> > "J. Clarke" <[email protected]> wrote in message
> > news:[email protected]...
> >
> > But if I have to push a button to stop the blade I may as well just
> > shove a pushstick into the side of it.
-MIKE- wrote:
> On 10/15/10 8:54 PM, Josepi wrote:
>> If you consider pushing an oak stick into the side of a carbide
>> toothed blade turning at 4500 PM as safe as pressing a pushbutton on
>> the side of the table saw you should never have children.
>>
>
> Here it is on video. I should have my testicles revoked.
>
> http://www.youtube.com/watch?v=XqFBPAXcX5U
You asshole! You had me on the edge of the toilet seat in near stark terror
throughout the entire video. But that closing comment still gets me
chuckling...
--
-Mike-
[email protected]
On Oct 15, 10:27=A0pm, -MIKE- <[email protected]> wrote:
> On 10/15/10 8:54 PM, Josepi wrote:
>
> > If you consider pushing an oak stick into the side of a carbide toothed
> > blade turning at 4500 PM as safe as pressing a pushbutton on the side o=
f the
> > table saw you should never have children.
>
> Here it is on video. =A0I should have my testicles revoked.
>
> http://www.youtube.com/watch?v=3DXqFBPAXcX5U
>
> --
>
> =A0 -MIKE-
>
> =A0 "Playing is not something I do at night, it's my function in life"
> =A0 =A0 =A0--Elvin Jones =A0(1927-2004)
> =A0 --
> =A0http://mikedrums.com
> =A0 [email protected]
> =A0 ---remove "DOT" ^^^^ to reply
You can SEE the rust forming....
On Oct 15, 6:50=A0pm, Stuart <[email protected]> wrote:
> In article <[email protected]>,
> =A0 =A0<[email protected]> wrote:
>
> > That's my point. Nobody else, so far, has addressed how they would
> > control the application of this "convenience brake", however
> > implemented. My pushbutton solution was rejected out of hand - but how
> > would any of the other suggested possibilities be implemented???
>
> OK, here goes:
>
> Pair of AC solenoids, one each side of the blade holding a brake pad away
> from the blade, paralleled with feed to motor. When motor is powered
> brakes are off, when motor switched off solenoids de-energise and springs
> press pads against sides of blade. This is a "convenience" brake, no need
> for great forces to be applied. Solenoids mounted on a sliding
> arrangement, operated by a lever, which allows them to be moved out of th=
e
> way for blade changing.
See? I knew there was a rational suggestion around. Now put some
pincer articulated bicycle brake pads at the bottom of the blade and
presto! same results.
Now the aggressiveness of the relief cuts in the blade bodies could
make the pads wear out rather quickly.
A pushbutton would still be safer than the possibility of oak rust flying
into your eyes.
"Robatoy" <[email protected]> wrote in message
news:dc30d880-6f26-4a09-8e04-8c0d248e3a24@f25g2000yqc.googlegroups.com...
You can SEE the rust forming....
On Fri, 15 Oct 2010 21:57:44 -0400, "Josepi" <[email protected]>
wrote:
>I haven't seen the SawStop demonstrated with a 45 degree tilt cut. Can it
>actually tilt? Has anybody actually seen the mechanism under the table?
>
>What happens when the sensitive moisture sensor is full of titanic acid oak
>sawdust?
>
>
Yes, it CAN tilt and cut a 45 degree cut. And if you cut damp wood, or
let sawdust build up it WILL false trigger - and that gets expensive.
Have one in the woodworking club shop.
I have seen the mechanism (about 3 years ago when they first got it
and it was triggered and needed the shoe replaced)
see:
http://www.sawdustonthefloor.com/wp-content/uploads/2009/08/Cartridge-Blade-Schematic-for-Saw-Stop.jpg
http://www.aetherczar.com/wp-content/uploads/SawStop-6813983-Fig2.jpg
It is mounted to the yoke assembly, behind the blade, and when it jams
into the blade the blade is pulled down into the table by the blade
inertia (basically it is disconnected from the depth adjustment when
the shoe fires, and the blade inertia sinks the blade)
>
>"J. Clarke" <[email protected]> wrote in message
>news:[email protected]...
>The same place the Sawstop mechanism goes.
>
>
>In article <[email protected]>, [email protected] says...
>
>> Me think we will wait until somebody shows a design drawing of where the
>> caliper goes when the saw blade tips at a 45 degree cut.
>
>
On 10/15/10 8:32 AM, J. Clarke wrote:
>> You want a convenience brake on an AC table saw? DC injection braking
>> is as simple as it gets and can be done by a reasonably adept
>> scrounger for less than $25 in less than an hour, with NO
>> modifications to the physical part of the saw. Just grabbing a few
>> parts out of my scrap bin I could have it working on a saw in less
>> than half an hour with no cash outlay at all. Not fully automated -
>> but hit the stop button or turn off the power and press a pushbutton
>> untill the blade stops (about 2 seconds) using nothing more than an
>> old PC power supply and a pushbutton switch. To make it a littlemore
>> foolproof the power switch would need to be replaces with a SPDT or
>> DPDT switch or augmented by a relay to prevent injecting the DC while
>> the AC was still connected.
>
> But if I have to push a button to stop the blade I may as well just
> shove a pushstick into the side of it.
>
Exactly, unless it's incorporated into the off switch.
If you do use a push stick, don't use oak.
It's VERY CORROSIVE and will disintegrate your saw blade.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/2010 10:52 AM, -MIKE- wrote:
> On 10/15/10 8:32 AM, J. Clarke wrote:
>> But if I have to push a button to stop the blade I may as well just
>> shove a pushstick into the side of it.
>
> Exactly, unless it's incorporated into the off switch.
>
> If you do use a push stick, don't use oak.
> It's VERY CORROSIVE and will disintegrate your saw blade.
LOL!
--
Free bad advice available here.
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/15/2010 1:16 PM, [email protected] wrote:
> OK - the whole premise of using a caliper, regardless of the source
> of the caliper, for a retrofit to an existing saw has all the
> drawbacks I have stated. OK, the corrosion might be a bit overstated -
> but it IS an issue that would have to be dealt with -nas it has to be
> dealt with in automotive, bicycle, and motorcycle applications. Using
> a caliper of any sort on the blade, even on a purpose built clean
> sheet saw design has engineering problems that would be best avoided
> due to complexity (like blade changing, adjustment for dado use, etc.)
> Putting the caliper (or drum) on the opposite end of the arbour
> handles most of those issues, but again, on a clean sheet design. As a
> retrofit it is still problematic.
That's a blanket statement. I would say that depends on the saw.
> Putting the brake on the motor is
> the simplest solution - wheather mechanical or electrical, and
> wheather direct drive or belt drive.
That's what I concluded after inspecting my saw (the Unisaw). Other saws may
be different.
> Either way, electrical application is the simplest, cheapest
> alternative (compared to hydraulic, mechanical, pneumatic, or
> percussive application) - and if you are going to use electical or
> electronic controls anyway, why not use electrical braking all the
> way?
In my case, it's because I can understand and implement mechanical devices;
electrical, not so much. If somebody were to implement and test and guarantee
an electrical braking system that could be retrofitted to my Unisaw I would
certainly be interested.
> That's my point. Nobody else, so far, has addressed how they would
> control the application of this "convenience brake", however
> implemented. My pushbutton solution was rejected out of hand - but how
> would any of the other suggested possibilities be implemented???
I don't recall rejecting yours, I only recall you rejecting mine... In any
case, for the Unisaw I think it would be relatively simple to actuate the brake
with a mechanical lever that's mounted in front of the power-off switch.
Initial pressure on the lever would actuate the power-off switch and cut power
to the motor, additional pressure would actuate the brake. This is exactly the
way the mechanical (automotive style drum) brake on my MiniMax bandsaw works.
And work it does; like a dream, and I can tell you that those upper and lower
drive wheels are about 20lbs apiece and have WAY (*WAY*!) more mass and
centrifugal force than a free-spinning table saw blade assembly.
> It is the only virtually universally implementable retrofit or add-on
> solution that does not require custom engineering for every saw it
> might possibly be applicable to.
>
> A lot of dreamers on the wreck - but how many implementers?
I have every confidence that I can implement a mechanical solution on my
Unisaw, and believe me, the naysayer attitude of a certain few (ahem) has just
about ticked me off enough to follow through with it. My only problem is
carving out the time to get it done; I have precious little of that these days.
So what's stopping YOU from being an implementer?
> Also, if electrical convenience braking is such a bad idea, why is it
> virtually the ONLY method used on commercially available table saws,
> particularly in the "consumer grade", "contractor", or "semi-pro"
> lines?
You never heard from *me* that it was a bad idea.
> Virtually every hand held circular saw on the market today has a
> "dynamic blade brake" as a standard feature as well.
> So does virtually every quality cut-off or miter saw.
My 3HP Makita plunge router has one and I love it. So does my Delta chop saw,
but that thing's a piece of crap in most every other respect, so I avoid using
it unless I have to.
> Best of all, it COULD be made as a simple plug-in module that you plug
> the saw into - replacing the existing power switch, on all but the
> higher end saws that use contactors instead of a simple switch.
>
> It could be made offshore, in reasonable quantities, to sell for less
> than $50 retail.
> It could be implemented, from scratch, by a reasonably competent
> tinkerer for under $100 buying all the parts new from local or online
> sources, and could be installed on ANY saw. Either as a plug in as
> above, or wired directly into the saw. Contacter controlled mabee add
> another $50.
I would have zero confidence in doing that unless I was working from plans
offered by another "tinkerer" who had already succeeded and was able to
demonstrate that it worked and was safe and that it wouldn't electrocute me or
destroy my saw. :-)
> Again - we are talking convenience brake - not emergency stop
Yep.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/15/10 6:29 PM, Robatoy wrote:
> Now the aggressiveness of the relief cuts in the blade bodies could
> make the pads wear out rather quickly.
Not as fast as that fu@&!ng oak dust!
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/10 8:54 PM, Josepi wrote:
> If you consider pushing an oak stick into the side of a carbide toothed
> blade turning at 4500 PM as safe as pressing a pushbutton on the side of the
> table saw you should never have children.
>
Here it is on video. I should have my testicles revoked.
http://www.youtube.com/watch?v=XqFBPAXcX5U
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/10 10:23 PM, Josepi wrote:
> A pushbutton would still be safer than the possibility of oak rust flying
> into your eyes.
>
I know that an electronic or mechanical technically be "safer," not to
mention more convenient. No one ever argued that it's a better
alternative. I only brought it up to show how easily a blade can be
stopped with very little pressure to one side of the blade.
I just thought it was laughable that you think it's somehow dangerous.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/2010 9:27 PM, -MIKE- wrote:
> On 10/15/10 8:54 PM, Josepi wrote:
>> If you consider pushing an oak stick into the side of a carbide toothed
>> blade turning at 4500 PM as safe as pressing a pushbutton on the side of the
>> table saw you should never have children.
>>
>
> Here it is on video. I should have my testicles revoked.
>
> http://www.youtube.com/watch?v=XqFBPAXcX5U
LOL! That's hilarious! :-)
--
"Even if your wife is happy but you're unhappy, you're still happier
than you'd be if you were happy and your wife was unhappy." - Red Green
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/15/10 11:38 PM, Steve Turner wrote:
> On 10/15/2010 10:23 PM, Josepi wrote:
>> A pushbutton would still be safer than the possibility of oak rust flying
>> into your eyes.
>
> "Oak rust"?
>
Every village needs a Dennis. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/16/10 8:11 AM, Mike Marlow wrote:
> -MIKE- wrote:
>> On 10/15/10 8:54 PM, Josepi wrote:
>>> If you consider pushing an oak stick into the side of a carbide
>>> toothed blade turning at 4500 PM as safe as pressing a pushbutton on
>>> the side of the table saw you should never have children.
>>>
>>
>> Here it is on video. I should have my testicles revoked.
>>
>> http://www.youtube.com/watch?v=XqFBPAXcX5U
>
> You asshole! You had me on the edge of the toilet seat in near stark terror
> throughout the entire video. But that closing comment still gets me
> chuckling...
>
I forgot the disclaimer. :-p
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>, Steve Turner <[email protected]> wrote:
>On 10/15/2010 10:23 PM, Josepi wrote:
>> A pushbutton would still be safer than the possibility of oak rust flying
>> into your eyes.
>
>"Oak rust"?
>
There's clearly a village somewhere in Canada that's missing its idiot.
On 10/17/10 10:41 PM, Mike Marlow wrote:
>>
>> Just in time for a sawdust fire! Oops.
>
> You arse - now you're changing the direction of this thread. We'll have to
> labor through fire hazards, fire extinuishers, and smoke detectors now....
>
Oak dust won't burn because it corrodes the fire right out.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Fri, 15 Oct 2010 13:28:28 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>> On Thu, 14 Oct 2010 22:14:49 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>>
>>> [email protected] wrote:
>>>
>>>>
>>>> First of all, it's just too big and heavy to fit.
>>>
>>> Why so? A caliper does not have to be large.
>>
>> One from a lincoln is!!!
>
>But Clare - no one is seriously suggesting a Lincold caliper. That was
>offered up tongue in cheek to provide an example of a solution. You really
>do not believe that this discussion has been about using a Lincoln caliper,
>do you?
>
>>> Sorry Clare - cannot trust you on this point. I see it as perfectly
>>> workable and not subject to any of the concerns you've outlined. I
>>> do understand both how the saw works and how calipers work but you
>>> have not argued anything to make the idea impractical.
>>
>>
>> It all depends on how fast you are stopping the blade, how big a pad
>> you are using, what pressure you are using, etc.
>>
>> I never said you could not desin a caliper type stopping device as a
>> convenience brake.
>
>I might be misunderstanding your position then. I have read what you wrote
>to be an ardent position against the viability of a caliper as a solution
>alternative. In my eyes, you seemed to have been rather adamant about that.
>If I misunderstood, then I apologize.
>
>>
>> I DID say there is NO WAY to effectivel use an automotive caliper
>> (lincoln) to do the job, and I DID say dynamic braking of one type or
>> other would be simpler, more effective, and more reliable.
>
>I have agreed that there could be alternative and potentially better ways,
>but I did not see your position as agruing against a Lincoln caliper as much
>as arguing against calipers in general.
>
>>
>> DONE
>
>Don't tell me when I'm done damnit!...
OK - the whole premise of using a caliper, regardless of the source
of the caliper, for a retrofit to an existing saw has all the
drawbacks I have stated. OK, the corrosion might be a bit overstated -
but it IS an issue that would have to be dealt with -nas it has to be
dealt with in automotive, bicycle, and motorcycle applications. Using
a caliper of any sort on the blade, even on a purpose built clean
sheet saw design has engineering problems that would be best avoided
due to complexity (like blade changing, adjustment for dado use, etc.)
Putting the caliper (or drum) on the opposite end of the arbour
handles most of those issues, but again, on a clean sheet design. As a
retrofit it is still problematic. Putting the brake on the motor is
the simplest solution - wheather mechanical or electrical, and
wheather direct drive or belt drive.
Either way, electrical application is the simplest, cheapest
alternative (compared to hydraulic, mechanical, pneumatic, or
percussive application) - and if you are going to use electical or
electronic controls anyway, why not use electrical braking all the
way?
That's my point. Nobody else, so far, has addressed how they would
control the application of this "convenience brake", however
implemented. My pushbutton solution was rejected out of hand - but how
would any of the other suggested possibilities be implemented???
It is the only virtually universally implementable retrofit or add-on
solution that does not require custom engineering for every saw it
might possibly be applicable to.
A lot of dreamers on the wreck - but how many implementers?
Also, if electrical convenience braking is such a bad idea, why is it
virtually the ONLY method used on commercially available table saws,
particularly in the "consumer grade", "contractor", or "semi-pro"
lines?
Virtually every hand held circular saw on the market today has a
"dynamic blade brake" as a standard feature as well.
So does virtually every quality cut-off or miter saw.
Best of all, it COULD be made as a simple plug-in module that you plug
the saw into - replacing the existing power switch, on all but the
higher end saws that use contactors instead of a simple switch.
It could be made offshore, in reasonable quantities, to sell for less
than $50 retail.
It could be implemented, from scratch, by a reasonably competent
tinkerer for under $100 buying all the parts new from local or online
sources, and could be installed on ANY saw. Either as a plug in as
above, or wired directly into the saw. Contacter controlled mabee add
another $50.
Again - we are talking convenience brake - not emergency stop
Another reado.
I have not idea where the trollers see I stated it was dangerous. I would do
it too.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
I know that an electronic or mechanical technically be "safer," not to
mention more convenient. No one ever argued that it's a better
alternative. I only brought it up to show how easily a blade can be
stopped with very little pressure to one side of the blade.
I just thought it was laughable that you think it's somehow dangerous.
On 10/15/10 10:23 PM, Josepi wrote:
> A pushbutton would still be safer than the possibility of oak rust flying
> into your eyes.
>
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
Now corrosion is our friend.
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Oak dust won't burn because it corrodes the fire right out.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
I believe there would be a definite danger factor difference parameter in
that one.
Usually convenient though.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
But if I have to push a button to stop the blade I may as well just
shove a pushstick into the side of it.
On Sat, 16 Oct 2010 21:29:05 -0400, "Mike Marlow"
<[email protected]> wrote:
>Larry Jaques wrote:
>
>>
>> I heartily disagree. The only solid ever thrown up at a brake caliper
>> in any quantity is water, and that runs right off. Sawdust would tend
>> to stick, especially in the inverted configuration it would have on a
>> table saw. 'Twould be especially bad with folks who "do Jummywood."
>>
>> Go ahead and prove me wrong, Mike. Mount one and see. I double dare
>> ya!
>
>I'm a sucker for a dare. Damnit... I agree the sawdust would stick, but I
>don't think that would be a real problem. It would be worn off the braking
>surface rather easily.
Just in time for a sawdust fire! Oops.
--
Know how to listen, and you will
profit even from those who talk badly.
-- Plutarch
I assume these regs are not enforced on saw sales then?
I know my sliding saw (cheapo) has a dynamic brake in it that slows it down
after a few seconds of power down but I do not have a T/S. The ones I have
seen (probably old units) spin forever after power off.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
The state that the blade must spin down in 10 seconds or less or else
the saw has to have permanent guard. The method they normally use won't
spin dado blades down in 10 seconds, so saws without permanent guards
are made with short arbors that can't take a dado.
In article <[email protected]>, [email protected]
says...
>
> I have no idea what EU regulations state or why they would care about a
> gradual stop of a saw blade.
>
> Are these regulations involved in convenience stopping of a table saw
> blade
> and what do they state?
In article <[email protected]>, markem618
@hotmail.com says...
>
> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >I suspect that a small pyrotechnic pressurizing one of the calipers off
> >my '76 Lincoln might surprise you.
>
> Yes but the heat will do what to the saw blade?
About the same thing it does to a brake rotor I suspect, polish the
sides a little bit.
In article <[email protected]>,
[email protected] says...
>
> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> <[email protected]> wrote:
>
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
> >>
> >> >J. Clarke wrote:
> >> >> In article<[email protected]>, [email protected] says...
> >> >>>
> >> >>> I would think that an emergency stop mechanism would be a whole different
> >> >>> magnitude than a scheduled, everyday, stop.
> >> >>>
> >> >>> For a finger saver an emergency stop mechanism would have to stop the blade
> >> >>> in a few teeth passings. For everyday usage a couple dozen blade rotations
> >> >>> would be OK too. These two situations would require different tactics.
> >> >>>
> >> >>> A dynamic electronic brake could vary the intensity for the two different
> >> >>> scenarios and we could add the caliper to the emerg stop. A caliper probably
> >> >>> wouldn't last long in everyday usage and would need to be adjusted and/or
> >> >>> replaced frequently.
> >> >>
> >> >> So how much power do you have to put into that electronic brake to stop
> >> >> the blade as fast as Sawstop's physical block?
> >> >>
> >> >> And why would a caliper not last long? A set of brake pads on a car
> >> >> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
> >> >> a lot more of a workout that they would stopping a little bitty saw
> >> >> blade that masses less than 1/1000 as much.
> >> >
> >> >The physics on that seem interesting. A little like stopping a speeding
> >> >bullet on a dime--it challenges my imagination. Probably not quite as
> >> >difficult as stopping a lightning bolt, but I wouldn't want to try that
> >> >either.
> >> >
> >> >Bill
> >> No way a caliper could stop the blade in even 4X the time the
> >> saw-stop does. And keeping dust out of the gap between tha "pad" and
> >> the blade would be quite problematic - with dust decreasing the
> >> stopping efficiency by a very large margin.
> >
> >I suspect that a small pyrotechnic pressurizing one of the calipers off
> >my '76 Lincoln might surprise you.
> >
> But would also be totally impractical on a 10" saw.
Why would it be "impractical on a 10" saw? The brake rotors on that car
are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
15" wheel.
On Fri, 15 Oct 2010 23:50:50 +0100, Stuart <[email protected]>
wrote:
>In article <[email protected]>,
> <[email protected]> wrote:
>
>> That's my point. Nobody else, so far, has addressed how they would
>> control the application of this "convenience brake", however
>> implemented. My pushbutton solution was rejected out of hand - but how
>> would any of the other suggested possibilities be implemented???
>
>OK, here goes:
>
>Pair of AC solenoids, one each side of the blade holding a brake pad away
>from the blade, paralleled with feed to motor. When motor is powered
>brakes are off, when motor switched off solenoids de-energise and springs
>press pads against sides of blade. This is a "convenience" brake, no need
>for great forces to be applied. Solenoids mounted on a sliding
>arrangement, operated by a lever, which allows them to be moved out of the
>way for blade changing.
That would work - assuming there is space to mount it and the
associated bracketry. Mechanically still more complex and therefore
prone to failure.
Generally speaking, an electronic implementation/solution is at least
twice as reliable as a mechanical solution, and the difference
increases as the mechanical complexity increases. More moving parts
means more to fail.
RE: Subjest
Time for a reality check.
Take your choice, dynamic or regenerative braking will never cut it as
a safety braking system.
Toss in disk brakes if that will make you happy.
All are much too slow to respond quickly enough to compete as a safety
device against SawStop.
As far as a braking system to bring a saw blade to a stop more
quickly, the economics will kill the idea.
The cost of a DC power supply, adjustable timer and a horsepower
rated, mechanically interlocked, set of contactors for a dynamic
braking system will be equal to or exceed the cost of a motor which
will also require added stator pegging to keep it from being ripped
loose from the motor housing.
Similar cost structures are4 in play for the other options.
Back to the drawing board.
Waiting for a T/S blade to stop spinning is a good time to collect
your thoughts.
When working around woodworking tools, patience is a virtue, IMHO.
Lew
On Oct 14, 7:52=A0pm, -MIKE- <[email protected]> wrote:
> On 10/14/10 6:40 PM, [email protected] wrote:
>
>
>
>
>
> > On Thu, 14 Oct 2010 17:26:59 -0500, -MIKE-<[email protected]>
> > wrote:
>
> >> On 10/14/10 5:06 PM, Robatoy wrote:
> >>> In article<[email protected]>,
> >>> =A0 [email protected] wrote:
>
> >>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> >>>> onto every surface of the caliper.
>
> >>> More corrosive than road salt?
>
> >> More corrosive than brake fluid? =A0 =A0Because calipers neeeeeever le=
ak.
> > =A0 Brake fluid itself is not corrosive. When it absorbs moisture it is=
-
> > and brake fluid is highly hygroscopic.
>
> I guess I was wrong then.
> sheesh
>
what does it feel like, Mike?
On Sat, 16 Oct 2010 12:10:40 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
>> [email protected] (Larry W) wrote:
>>
>> >In article <[email protected]>,
>> > <[email protected]> wrote:
>> ><...snipped...>
>> >>Generally speaking, an electronic implementation/solution is at least
>> >>twice as reliable as a mechanical solution, and the difference
>> >>increases as the mechanical complexity increases. More moving parts
>> >>means more to fail.
>> >
>> >Then why don't we have automotive brakes that work that way?
>> >
>> >
>> Electronic braking IS employed on virtually all electric and hybrid
>> vehicles - and virtually NO motor vehicle on the road today uses
>> "mechanical" brakes - since hydraulics, having fewer moving parts,
>> meet the requirement and are much more reliable than the mechanicals.
>
>Your distinction between "mechanical" and "hydraulic" is a clear attempt
>at shifting the discussion. And your mentioning it so late suggests
>that you yourself are just parroting what someone else told you.
No, and I, unlike the vast majority of you guys, have actually driven
cars with true mechanical brakes.
cable only on the '49 VeeDub and rod brakes on the Chevie.
>
>As for electric and hybrid vehicles having "electronic brakes", they
>have regenerative braking systems, just as trolleys and electric
>locomotives have had for decades, but those are not substitutes for the
>conventional brake.
>
No, but they do roughly 80% of the job.
Lew Hodgett wrote:
> RE: Subjest
>
> Time for a reality check.
>
> Take your choice, dynamic or regenerative braking will never cut it as
> a safety braking system.
>
> Toss in disk brakes if that will make you happy.
>
> All are much too slow to respond quickly enough to compete as a safety
> device against SawStop.
That has never been the intent of this discussion. So - you are correct,
but it's not relevant.
--
-Mike-
[email protected]
In article <[email protected]>,
[email protected] says...
>
> On Thu, 14 Oct 2010 16:38:53 -0500, -MIKE- <[email protected]>
> wrote:
>
> >On 10/14/10 4:22 PM, Steve Turner wrote:
> >>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> >>> onto every surface of the caliper.
> >>
> >> Geez Chicken Little, how many mountains are you going to make out of
> >> molehills on this topic? Just about every point you've tried to make has
> >> had the air of doom, disaster, and failure. This ain't that friggin'
> >> difficult, Penelope.
> >>
> >
> >And since when is Oak sawdust corrosive... no, I'm sorry..."VERY
> >CORROSIVE?"
>
> Never see the black staining in oak from non-galvanized nails? That is
> due to corrosion. Doesn't take much corrosion to make a caliper just
> fussy enough that it might not do the required job (for which it was
> not designed).
What, a disk brake caliper is not designed to stop a metal disk from
turning? So for what _is_ it designed?
And when did oak in a dry shop become more corrosive than salt on a wet
road?
> See also:
> http://www.scribd.com/doc/36276187/Corrosion-of-Metals-by-Wood
Yeah, you stick a nail in a piece of oak and let it soak in water for a
few years and you'll get corrosion. There's no piece of oak here, and
no soaking in water. If corrosion from oak is an issue you should be
more worried about your blade and arbor and bearings than about the
brake caliper.
You gotta be an electrical engineer--only an EE could be so paranoid
about a simple mechanical device.
> >I saw my fair amount of oak and I'm not exactly a neat guy in the shop.
> >I clean up my saw dust when it pisses me off enough, which is usually
> >when it's in the way of the next project, which means, it can sit around
> >under the saw, on my tools, all kinds of other metal, plastic, and
> >rubber stuff, including the end of this run-on sentence, for months at a
> >time.
> >
> >I haven't seen it corrode a single thing.
> >(This should cue some pseudo scientific diatribe about some oil in oak,
> >contained in a minuscule amout, which is technically an acid or oxidizer
> >of some sort which *can* corrode *something* on planet earth.)
In article <[email protected]>,
[email protected] says...
>
> On Fri, 15 Oct 2010 23:50:50 +0100, Stuart <[email protected]>
> wrote:
>
> >In article <[email protected]>,
> > <[email protected]> wrote:
> >
> >> That's my point. Nobody else, so far, has addressed how they would
> >> control the application of this "convenience brake", however
> >> implemented. My pushbutton solution was rejected out of hand - but how
> >> would any of the other suggested possibilities be implemented???
> >
> >OK, here goes:
> >
> >Pair of AC solenoids, one each side of the blade holding a brake pad away
> >from the blade, paralleled with feed to motor. When motor is powered
> >brakes are off, when motor switched off solenoids de-energise and springs
> >press pads against sides of blade. This is a "convenience" brake, no need
> >for great forces to be applied. Solenoids mounted on a sliding
> >arrangement, operated by a lever, which allows them to be moved out of the
> >way for blade changing.
> That would work - assuming there is space to mount it and the
> associated bracketry. Mechanically still more complex and therefore
> prone to failure.
>
> Generally speaking, an electronic implementation/solution is at least
> twice as reliable as a mechanical solution, and the difference
> increases as the mechanical complexity increases. More moving parts
> means more to fail.
And that is why all cars have electronic brakes . . .
In article <s39uo.304$s%[email protected]>, [email protected] says...
>
> They do. How many cars have you seen that have cables running to the rear
> brake lights?
>
When you sober up get back to me.
>
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> And that is why all cars have electronic brakes . . .
In article <[email protected]>,
[email protected] says...
>
> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
> [email protected] (Larry W) wrote:
>
> >In article <[email protected]>,
> > <[email protected]> wrote:
> ><...snipped...>
> >>Generally speaking, an electronic implementation/solution is at least
> >>twice as reliable as a mechanical solution, and the difference
> >>increases as the mechanical complexity increases. More moving parts
> >>means more to fail.
> >
> >Then why don't we have automotive brakes that work that way?
> >
> >
> Electronic braking IS employed on virtually all electric and hybrid
> vehicles - and virtually NO motor vehicle on the road today uses
> "mechanical" brakes - since hydraulics, having fewer moving parts,
> meet the requirement and are much more reliable than the mechanicals.
Your distinction between "mechanical" and "hydraulic" is a clear attempt
at shifting the discussion. And your mentioning it so late suggests
that you yourself are just parroting what someone else told you.
As for electric and hybrid vehicles having "electronic brakes", they
have regenerative braking systems, just as trolleys and electric
locomotives have had for decades, but those are not substitutes for the
conventional brake.
In article <[email protected]>,
[email protected] says...
>
> In article <[email protected]>,
> J. Clarke <[email protected]> wrote:
> >In article <[email protected]>,
> >[email protected] says...
> >>
> >> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
> >> [email protected] (Larry W) wrote:
> >>
> >> >In article <[email protected]>,
> >> > <[email protected]> wrote:
> >> ><...snipped...>
> >> >>Generally speaking, an electronic implementation/solution is at least
> >> >>twice as reliable as a mechanical solution, and the difference
> >> >>increases as the mechanical complexity increases. More moving parts
> >> >>means more to fail.
> >> >
> >> >Then why don't we have automotive brakes that work that way?
> >> >
> >> >
> >> Electronic braking IS employed on virtually all electric and hybrid
> >> vehicles - and virtually NO motor vehicle on the road today uses
> >> "mechanical" brakes - since hydraulics, having fewer moving parts,
> >> meet the requirement and are much more reliable than the mechanicals.
> >
> >Your distinction between "mechanical" and "hydraulic" is a clear attempt
> >at shifting the discussion. And your mentioning it so late suggests
> >that you yourself are just parroting what someone else told you.
> >
> >As for electric and hybrid vehicles having "electronic brakes", they
> >have regenerative braking systems, just as trolleys and electric
> >locomotives have had for decades, but those are not substitutes for the
> >conventional brake.
> >
> >
>
> In the context of this discussion, an automotive style disc brake caliper
> is being considered as a means of stopping a table saw blade. Clearly,
> hydraulics are involved. YOU are the one, who within that context, made
> the comparison of reliability between mechanical and electronic systems.
> Now it appears that YOU are making a distinction between hydraulic and
> mechanical so that the scarcity of electronically actuated automotive
> brakes does not conflict with your earlier assertion.
>
> By the way, by most measures, it would be a stretch to call the earliest
> examples of regenrative braking "electronic"
Larry, be careful with your attributions. You are replying to one of
jclarke's posts but contesting points raised by clare@snyder as if they
were raised by jclarke.
In article <[email protected]>,
[email protected] says...
>
> On Sat, 16 Oct 2010 21:25:34 +0000 (UTC),
> [email protected] (Larry W) wrote:
>
> >In article <[email protected]>,
> >J. Clarke <[email protected]> wrote:
> >>In article <[email protected]>,
> >>[email protected] says...
> >>>
> >>> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
> >>> [email protected] (Larry W) wrote:
> >>>
> >>> >In article <[email protected]>,
> >>> > <[email protected]> wrote:
> >>> ><...snipped...>
> >>> >>Generally speaking, an electronic implementation/solution is at least
> >>> >>twice as reliable as a mechanical solution, and the difference
> >>> >>increases as the mechanical complexity increases. More moving parts
> >>> >>means more to fail.
> >>> >
> >>> >Then why don't we have automotive brakes that work that way?
> >>> >
> >>> >
> >>> Electronic braking IS employed on virtually all electric and hybrid
> >>> vehicles - and virtually NO motor vehicle on the road today uses
> >>> "mechanical" brakes - since hydraulics, having fewer moving parts,
> >>> meet the requirement and are much more reliable than the mechanicals.
> >>
> >>Your distinction between "mechanical" and "hydraulic" is a clear attempt
> >>at shifting the discussion. And your mentioning it so late suggests
> >>that you yourself are just parroting what someone else told you.
> >>
> >>As for electric and hybrid vehicles having "electronic brakes", they
> >>have regenerative braking systems, just as trolleys and electric
> >>locomotives have had for decades, but those are not substitutes for the
> >>conventional brake.
> >>
> >>
> >
> >In the context of this discussion, an automotive style disc brake caliper
> >is being considered as a means of stopping a table saw blade. Clearly,
> >hydraulics are involved. YOU are the one, who within that context, made
> >the comparison of reliability between mechanical and electronic systems.
> >Now it appears that YOU are making a distinction between hydraulic and
> >mechanical so that the scarcity of electronically actuated automotive
> >brakes does not conflict with your earlier assertion.
> >
> >By the way, by most measures, it would be a stretch to call the earliest
> >examples of regenrative braking "electronic"
> >
> >
> Who's talking the "earliest examples" - I'm talking "current"
> electrical and hybrid vehicle technology - ALL of which are computer
> controlled.
> ANd there is a difference between "regenerative" and "dynamic"
> Deisel electric locos with their large resistive braking arrays are
> "dynamic" while the same type of system on a battery powered or hybrid
> vehicle is "regenerative" because the power is being captured to
> recharge the battery, not wasted, as in a normal brake , as heat.
>
> At least that has been the common useage.
All of these pedantic little distinctions you make are starting to get
boring.
On Sat, 16 Oct 2010 21:25:34 +0000 (UTC),
[email protected] (Larry W) wrote:
>In article <[email protected]>,
>J. Clarke <[email protected]> wrote:
>>In article <[email protected]>,
>>[email protected] says...
>>>
>>> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
>>> [email protected] (Larry W) wrote:
>>>
>>> >In article <[email protected]>,
>>> > <[email protected]> wrote:
>>> ><...snipped...>
>>> >>Generally speaking, an electronic implementation/solution is at least
>>> >>twice as reliable as a mechanical solution, and the difference
>>> >>increases as the mechanical complexity increases. More moving parts
>>> >>means more to fail.
>>> >
>>> >Then why don't we have automotive brakes that work that way?
>>> >
>>> >
>>> Electronic braking IS employed on virtually all electric and hybrid
>>> vehicles - and virtually NO motor vehicle on the road today uses
>>> "mechanical" brakes - since hydraulics, having fewer moving parts,
>>> meet the requirement and are much more reliable than the mechanicals.
>>
>>Your distinction between "mechanical" and "hydraulic" is a clear attempt
>>at shifting the discussion. And your mentioning it so late suggests
>>that you yourself are just parroting what someone else told you.
>>
>>As for electric and hybrid vehicles having "electronic brakes", they
>>have regenerative braking systems, just as trolleys and electric
>>locomotives have had for decades, but those are not substitutes for the
>>conventional brake.
>>
>>
>
>In the context of this discussion, an automotive style disc brake caliper
>is being considered as a means of stopping a table saw blade. Clearly,
>hydraulics are involved. YOU are the one, who within that context, made
>the comparison of reliability between mechanical and electronic systems.
>Now it appears that YOU are making a distinction between hydraulic and
>mechanical so that the scarcity of electronically actuated automotive
>brakes does not conflict with your earlier assertion.
>
>By the way, by most measures, it would be a stretch to call the earliest
>examples of regenrative braking "electronic"
>
>
Who's talking the "earliest examples" - I'm talking "current"
electrical and hybrid vehicle technology - ALL of which are computer
controlled.
ANd there is a difference between "regenerative" and "dynamic"
Deisel electric locos with their large resistive braking arrays are
"dynamic" while the same type of system on a battery powered or hybrid
vehicle is "regenerative" because the power is being captured to
recharge the battery, not wasted, as in a normal brake , as heat.
At least that has been the common useage.
Funny how we keep going back to that concept...LOL
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
Reality check.
We don't give a crap because we're not talking about a safety stop.
On Thu, 14 Oct 2010 17:26:59 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 5:06 PM, Robatoy wrote:
>> In article<[email protected]>,
>> [email protected] wrote:
>>
>>>
>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>>> onto every surface of the caliper.
>>
>> More corrosive than road salt?
>
>More corrosive than brake fluid? Because calipers neeeeeever leak.
Brake fluid itself is not corrosive. When it absorbs moisture it is -
and brake fluid is highly hygroscopic.
On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
[email protected] (Larry W) wrote:
>In article <[email protected]>,
> <[email protected]> wrote:
><...snipped...>
>>Generally speaking, an electronic implementation/solution is at least
>>twice as reliable as a mechanical solution, and the difference
>>increases as the mechanical complexity increases. More moving parts
>>means more to fail.
>
>Then why don't we have automotive brakes that work that way?
>
>
Electronic braking IS employed on virtually all electric and hybrid
vehicles - and virtually NO motor vehicle on the road today uses
"mechanical" brakes - since hydraulics, having fewer moving parts,
meet the requirement and are much more reliable than the mechanicals.
[email protected] wrote:
>
> Never see the black staining in oak from non-galvanized nails? That is
> due to corrosion. Doesn't take much corrosion to make a caliper just
> fussy enough that it might not do the required job (for which it was
> not designed).
>
I thought you worked on cars Clare. Have you ever seen a caliper that was
*not corroded*? You're exagerating things in attempt to bolster your point
but again, it's just not true.
--
-Mike-
[email protected]
On 10/14/10 6:39 PM, [email protected] wrote:
>>> Geez Chicken Little, how many mountains are you going to make out of
>>> molehills on this topic? Just about every point you've tried to make has
>>> had the air of doom, disaster, and failure. This ain't that friggin'
>>> difficult, Penelope.
>>>
>>
>> And since when is Oak sawdust corrosive... no, I'm sorry..."VERY
>> CORROSIVE?"
>
> Never see the black staining in oak from non-galvanized nails? That is
> due to corrosion. Doesn't take much corrosion to make a caliper just
> fussy enough that it might not do the required job (for which it was
> not designed).
>
Yep, as predicted. :-p
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 6:40 PM, [email protected] wrote:
> On Thu, 14 Oct 2010 17:26:59 -0500, -MIKE-<[email protected]>
> wrote:
>
>> On 10/14/10 5:06 PM, Robatoy wrote:
>>> In article<[email protected]>,
>>> [email protected] wrote:
>>>
>>>>
>>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>>>> onto every surface of the caliper.
>>>
>>> More corrosive than road salt?
>>
>> More corrosive than brake fluid? Because calipers neeeeeever leak.
> Brake fluid itself is not corrosive. When it absorbs moisture it is -
> and brake fluid is highly hygroscopic.
I guess I was wrong then.
sheesh
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 7:01 PM, Robatoy wrote:
> On Oct 14, 7:52 pm, -MIKE-<[email protected]> wrote:
>> On 10/14/10 6:40 PM, [email protected] wrote:
>>
>>
>>
>>
>>
>>> On Thu, 14 Oct 2010 17:26:59 -0500, -MIKE-<[email protected]>
>>> wrote:
>>
>>>> On 10/14/10 5:06 PM, Robatoy wrote:
>>>>> In article<[email protected]>,
>>>>> [email protected] wrote:
>>
>>>>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>>>>>> onto every surface of the caliper.
>>
>>>>> More corrosive than road salt?
>>
>>>> More corrosive than brake fluid? Because calipers neeeeeever leak.
>>> Brake fluid itself is not corrosive. When it absorbs moisture it is -
>>> and brake fluid is highly hygroscopic.
>>
>> I guess I was wrong then.
>> sheesh
>>
> what does it feel like, Mike?
>
I was being fesesiou.... phesesu... feseeshus..... sarcastic.
I thought I was wrong once, but I was mistaken.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 10:43 PM, Lew Hodgett wrote:
> RE: Subjest
>
> Time for a reality check.
>
> Take your choice, dynamic or regenerative braking will never cut it as
> a safety braking system.
>
> Toss in disk brakes if that will make you happy.
>
> All are much too slow to respond quickly enough to compete as a safety
> device against SawStop.
>
Reality check.
We don't give a crap because we're not talking about a safety stop.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>,
<[email protected]> wrote:
<...snipped...>
>Generally speaking, an electronic implementation/solution is at least
>twice as reliable as a mechanical solution, and the difference
>increases as the mechanical complexity increases. More moving parts
>means more to fail.
Then why don't we have automotive brakes that work that way?
--
When the game is over, the pawn and the king are returned to the same box.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org
On 10/15/10 10:34 PM, Josepi wrote:
> They do. How many cars have you seen that have cables running to the rear
> brake lights?
>
What grade are you in?
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>,
J. Clarke <[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
>> [email protected] (Larry W) wrote:
>>
>> >In article <[email protected]>,
>> > <[email protected]> wrote:
>> ><...snipped...>
>> >>Generally speaking, an electronic implementation/solution is at least
>> >>twice as reliable as a mechanical solution, and the difference
>> >>increases as the mechanical complexity increases. More moving parts
>> >>means more to fail.
>> >
>> >Then why don't we have automotive brakes that work that way?
>> >
>> >
>> Electronic braking IS employed on virtually all electric and hybrid
>> vehicles - and virtually NO motor vehicle on the road today uses
>> "mechanical" brakes - since hydraulics, having fewer moving parts,
>> meet the requirement and are much more reliable than the mechanicals.
>
>Your distinction between "mechanical" and "hydraulic" is a clear attempt
>at shifting the discussion. And your mentioning it so late suggests
>that you yourself are just parroting what someone else told you.
>
>As for electric and hybrid vehicles having "electronic brakes", they
>have regenerative braking systems, just as trolleys and electric
>locomotives have had for decades, but those are not substitutes for the
>conventional brake.
>
>
In the context of this discussion, an automotive style disc brake caliper
is being considered as a means of stopping a table saw blade. Clearly,
hydraulics are involved. YOU are the one, who within that context, made
the comparison of reliability between mechanical and electronic systems.
Now it appears that YOU are making a distinction between hydraulic and
mechanical so that the scarcity of electronically actuated automotive
brakes does not conflict with your earlier assertion.
By the way, by most measures, it would be a stretch to call the earliest
examples of regenrative braking "electronic"
--
When the game is over, the pawn and the king are returned to the same box.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org
On Thu, 14 Oct 2010 16:38:53 -0500, -MIKE- <[email protected]>
wrote:
>On 10/14/10 4:22 PM, Steve Turner wrote:
>>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>>> onto every surface of the caliper.
>>
>> Geez Chicken Little, how many mountains are you going to make out of
>> molehills on this topic? Just about every point you've tried to make has
>> had the air of doom, disaster, and failure. This ain't that friggin'
>> difficult, Penelope.
>>
>
>And since when is Oak sawdust corrosive... no, I'm sorry..."VERY
>CORROSIVE?"
Never see the black staining in oak from non-galvanized nails? That is
due to corrosion. Doesn't take much corrosion to make a caliper just
fussy enough that it might not do the required job (for which it was
not designed).
See also:
http://www.scribd.com/doc/36276187/Corrosion-of-Metals-by-Wood
>
>I saw my fair amount of oak and I'm not exactly a neat guy in the shop.
>I clean up my saw dust when it pisses me off enough, which is usually
>when it's in the way of the next project, which means, it can sit around
>under the saw, on my tools, all kinds of other metal, plastic, and
>rubber stuff, including the end of this run-on sentence, for months at a
>time.
>
>I haven't seen it corrode a single thing.
>(This should cue some pseudo scientific diatribe about some oil in oak,
>contained in a minuscule amout, which is technically an acid or oxidizer
>of some sort which *can* corrode *something* on planet earth.)
On Sat, 16 Oct 2010 21:36:09 -0400, "J. Clarke"
<[email protected]> wrote:
>In article <[email protected]>,
>[email protected] says...
>>
>> On Sat, 16 Oct 2010 21:25:34 +0000 (UTC),
>> [email protected] (Larry W) wrote:
>>
>> >In article <[email protected]>,
>> >J. Clarke <[email protected]> wrote:
>> >>In article <[email protected]>,
>> >>[email protected] says...
>> >>>
>> >>> On Sat, 16 Oct 2010 03:40:59 +0000 (UTC),
>> >>> [email protected] (Larry W) wrote:
>> >>>
>> >>> >In article <[email protected]>,
>> >>> > <[email protected]> wrote:
>> >>> ><...snipped...>
>> >>> >>Generally speaking, an electronic implementation/solution is at least
>> >>> >>twice as reliable as a mechanical solution, and the difference
>> >>> >>increases as the mechanical complexity increases. More moving parts
>> >>> >>means more to fail.
>> >>> >
>> >>> >Then why don't we have automotive brakes that work that way?
>> >>> >
>> >>> >
>> >>> Electronic braking IS employed on virtually all electric and hybrid
>> >>> vehicles - and virtually NO motor vehicle on the road today uses
>> >>> "mechanical" brakes - since hydraulics, having fewer moving parts,
>> >>> meet the requirement and are much more reliable than the mechanicals.
>> >>
>> >>Your distinction between "mechanical" and "hydraulic" is a clear attempt
>> >>at shifting the discussion. And your mentioning it so late suggests
>> >>that you yourself are just parroting what someone else told you.
>> >>
>> >>As for electric and hybrid vehicles having "electronic brakes", they
>> >>have regenerative braking systems, just as trolleys and electric
>> >>locomotives have had for decades, but those are not substitutes for the
>> >>conventional brake.
>> >>
>> >>
>> >
>> >In the context of this discussion, an automotive style disc brake caliper
>> >is being considered as a means of stopping a table saw blade. Clearly,
>> >hydraulics are involved. YOU are the one, who within that context, made
>> >the comparison of reliability between mechanical and electronic systems.
>> >Now it appears that YOU are making a distinction between hydraulic and
>> >mechanical so that the scarcity of electronically actuated automotive
>> >brakes does not conflict with your earlier assertion.
>> >
>> >By the way, by most measures, it would be a stretch to call the earliest
>> >examples of regenrative braking "electronic"
>> >
>> >
>> Who's talking the "earliest examples" - I'm talking "current"
>> electrical and hybrid vehicle technology - ALL of which are computer
>> controlled.
>> ANd there is a difference between "regenerative" and "dynamic"
>> Deisel electric locos with their large resistive braking arrays are
>> "dynamic" while the same type of system on a battery powered or hybrid
>> vehicle is "regenerative" because the power is being captured to
>> recharge the battery, not wasted, as in a normal brake , as heat.
>>
>> At least that has been the common useage.
>
>All of these pedantic little distinctions you make are starting to get
>boring.
>
Nice to know the difference between a fox terrier and a fox - or a
wolf hound and a wolf. The little distinctions can make a big
difference in the real world.
They do. How many cars have you seen that have cables running to the rear
brake lights?
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
And that is why all cars have electronic brakes . . .
In article <[email protected]>, [email protected] says...
>
> The electornic way would be so much gentler and easier to implement. They
> work like a charm.
>
> Maybe only because of the background of the guys proposing it.
If it "works like a charm" then why can't it slow a dado fast enough to
meet EU regulations?
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> Why would it be "impractical on a 10" saw? The brake rotors on that car
> are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
> 15" wheel.
In article <[email protected]>, [email protected]
says...
>
> I have no idea what EU regulations state or why they would care about a
> gradual stop of a saw blade.
>
> Are these regulations involved in convenience stopping of a table saw blade
> and what do they state?
The state that the blade must spin down in 10 seconds or less or else
the saw has to have permanent guard. The method they normally use won't
spin dado blades down in 10 seconds, so saws without permanent guards
are made with short arbors that can't take a dado.
> "J. Clarke" <[email protected]> wrote in message
> news:[email protected]...
> If it "works like a charm" then why can't it slow a dado fast enough to
> meet EU regulations?
>
>
>
> In article <[email protected]>, [email protected] says...
> >
> > The electornic way would be so much gentler and easier to implement. They
> > work like a charm.
> >
> > Maybe only because of the background of the guys proposing it.
On 10/12/2010 5:46 PM, [email protected] wrote:
> On Tue, 12 Oct 2010 11:28:12 -0400, "Josepi"<[email protected]>
> wrote:
>
>>
>> 17 teeth?
>>
>> How fast can you push your finger?
>>
>>
>>
>> "-MIKE-"<[email protected]> wrote in message
>> news:[email protected]...
>> That may be true, but they still don't do any harm.
>>
>>
>>
>>> Sawstop stops the blade in 1/200 of a second, according to their Web
>>> site. At 3450 RPM that means the blade stops in .29 revolution, which
>>> with a 60 tooth blade means that 17 teeth have had a shot at your
>>> finger.
>>>
> Actually significantly LESS than 17 teeth, because the blade is very
> quickly slowing down throughout that 1/200 of a second. I believe the
> number is something like SEVEN teeth pass the gullet from the time of
> contact to full stop, and the last 3 or 4 are pretty well stopped as
> they go by.
> A demonstation showed a damp peice of cardboard stop the saw with
> barely a nick in it.
Another important part of the SawStop design is that the blade is dropped
below the table's surface as the blade is being stopped.
The electornic way would be so much gentler and easier to implement. They
work like a charm.
Maybe only because of the background of the guys proposing it.
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
Why would it be "impractical on a 10" saw? The brake rotors on that car
are IIRC 11.5 inch diameter and the whole brake assembly fits inside a
15" wheel.
On Tue, 12 Oct 2010 11:28:12 -0400, "Josepi" <[email protected]>
wrote:
>
>17 teeth?
>
>How fast can you push your finger?
>
>
>
>"-MIKE-" <[email protected]> wrote in message
>news:[email protected]...
>That may be true, but they still don't do any harm.
>
>
>
>> Sawstop stops the blade in 1/200 of a second, according to their Web
>> site. At 3450 RPM that means the blade stops in .29 revolution, which
>> with a 60 tooth blade means that 17 teeth have had a shot at your
>> finger.
>>
Actually significantly LESS than 17 teeth, because the blade is very
quickly slowing down throughout that 1/200 of a second. I believe the
number is something like SEVEN teeth pass the gullet from the time of
contact to full stop, and the last 3 or 4 are pretty well stopped as
they go by.
A demonstation showed a damp peice of cardboard stop the saw with
barely a nick in it.
On 10/13/10 7:44 AM, Markem wrote:
> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
> <[email protected]> wrote:
>
>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>> my '76 Lincoln might surprise you.
>
> Yes but the heat will do what to the saw blade?
>
> Mark
Nothing.
A lot more heat is generated by cutting than would be generated in the
half second it would take to slow down the blade.
You guys do realize we're not leaving the motor on in this scenario,
right? :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
-MIKE- wrote:
> On 10/13/10 7:44 AM, Markem wrote:
>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>> <[email protected]> wrote:
>>
>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>> my '76 Lincoln might surprise you.
>>
>> Yes but the heat will do what to the saw blade?
>>
>> Mark
>
> Nothing.
> A lot more heat is generated by cutting than would be generated in the
> half second it would take to slow down the blade.
>
> You guys do realize we're not leaving the motor on in this scenario,
> right? :-)
>
Yep, thought of that. Gotta break the problem into parts (important
trick/secret!) : ) I didn't count the mass of the rotor either, or it's
attached parts, in my other post either. I'm curious now though about
the calculation (foot/lbs of force).
Bill
On 10/13/10 11:22 AM, Bill wrote:
> -MIKE- wrote:
>> On 10/13/10 7:44 AM, Markem wrote:
>>> On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
>>> <[email protected]> wrote:
>>>
>>>> I suspect that a small pyrotechnic pressurizing one of the calipers off
>>>> my '76 Lincoln might surprise you.
>>>
>>> Yes but the heat will do what to the saw blade?
>>>
>>> Mark
>>
>> Nothing.
>> A lot more heat is generated by cutting than would be generated in the
>> half second it would take to slow down the blade.
>>
>> You guys do realize we're not leaving the motor on in this scenario,
>> right? :-)
>>
>
> Yep, thought of that. Gotta break the problem into parts (important
> trick/secret!) : ) I didn't count the mass of the rotor either, or it's
> attached parts, in my other post either. I'm curious now though about
> the calculation (foot/lbs of force).
>
> Bill
>
Sometimes all it takes is a couple of scraps of wood to show how
"little" force is needed. Haven't you ever stopped a coasting blade with
a scrap of wood?
I still see people talking about the SawStop and what it takes for an
emergency stop of the blade. I don't know about anyone else, but all I'm
talking about is a convenience stop.
I suspect a blade could be stopped (at shut-off) in less that a second
with something the size of a bicycle brake and a spring.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
I have no idea what EU regulations state or why they would care about a
gradual stop of a saw blade.
Are these regulations involved in convenience stopping of a table saw blade
and what do they state?
"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
If it "works like a charm" then why can't it slow a dado fast enough to
meet EU regulations?
In article <[email protected]>, [email protected] says...
>
> The electornic way would be so much gentler and easier to implement. They
> work like a charm.
>
> Maybe only because of the background of the guys proposing it.
On Tue, 12 Oct 2010 22:25:50 -0400, "J. Clarke"
<[email protected]> wrote:
>I suspect that a small pyrotechnic pressurizing one of the calipers off
>my '76 Lincoln might surprise you.
Yes but the heat will do what to the saw blade?
Mark
On Mon, 11 Oct 2010 19:59:30 -0400, Bill <[email protected]> wrote:
>J. Clarke wrote:
>> In article<[email protected]>, [email protected] says...
>>>
>>> I would think that an emergency stop mechanism would be a whole different
>>> magnitude than a scheduled, everyday, stop.
>>>
>>> For a finger saver an emergency stop mechanism would have to stop the blade
>>> in a few teeth passings. For everyday usage a couple dozen blade rotations
>>> would be OK too. These two situations would require different tactics.
>>>
>>> A dynamic electronic brake could vary the intensity for the two different
>>> scenarios and we could add the caliper to the emerg stop. A caliper probably
>>> wouldn't last long in everyday usage and would need to be adjusted and/or
>>> replaced frequently.
>>
>> So how much power do you have to put into that electronic brake to stop
>> the blade as fast as Sawstop's physical block?
>>
>> And why would a caliper not last long? A set of brake pads on a car
>> with 10" rotors lasts 40,000 miles or so, and they're getting a Hell of
>> a lot more of a workout that they would stopping a little bitty saw
>> blade that masses less than 1/1000 as much.
>
>The physics on that seem interesting. A little like stopping a speeding
>bullet on a dime--it challenges my imagination. Probably not quite as
>difficult as stopping a lightning bolt, but I wouldn't want to try that
>either.
>
>Bill
No way a caliper could stop the blade in even 4X the time the
saw-stop does. And keeping dust out of the gap between tha "pad" and
the blade would be quite problematic - with dust decreasing the
stopping efficiency by a very large margin.
Larry Jaques wrote:
>
> I heartily disagree. The only solid ever thrown up at a brake caliper
> in any quantity is water, and that runs right off. Sawdust would tend
> to stick, especially in the inverted configuration it would have on a
> table saw. 'Twould be especially bad with folks who "do Jummywood."
>
> Go ahead and prove me wrong, Mike. Mount one and see. I double dare
> ya!
I'm a sucker for a dare. Damnit... I agree the sawdust would stick, but I
don't think that would be a real problem. It would be worn off the braking
surface rather easily.
--
-Mike-
[email protected]
[email protected] wrote:
> On Thu, 14 Oct 2010 22:14:49 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> [email protected] wrote:
>>
>>>
>>> First of all, it's just too big and heavy to fit.
>>
>> Why so? A caliper does not have to be large.
>
> One from a lincoln is!!!
But Clare - no one is seriously suggesting a Lincold caliper. That was
offered up tongue in cheek to provide an example of a solution. You really
do not believe that this discussion has been about using a Lincoln caliper,
do you?
>> Sorry Clare - cannot trust you on this point. I see it as perfectly
>> workable and not subject to any of the concerns you've outlined. I
>> do understand both how the saw works and how calipers work but you
>> have not argued anything to make the idea impractical.
>
>
> It all depends on how fast you are stopping the blade, how big a pad
> you are using, what pressure you are using, etc.
>
> I never said you could not desin a caliper type stopping device as a
> convenience brake.
I might be misunderstanding your position then. I have read what you wrote
to be an ardent position against the viability of a caliper as a solution
alternative. In my eyes, you seemed to have been rather adamant about that.
If I misunderstood, then I apologize.
>
> I DID say there is NO WAY to effectivel use an automotive caliper
> (lincoln) to do the job, and I DID say dynamic braking of one type or
> other would be simpler, more effective, and more reliable.
I have agreed that there could be alternative and potentially better ways,
but I did not see your position as agruing against a Lincoln caliper as much
as arguing against calipers in general.
>
> DONE
Don't tell me when I'm done damnit!...
--
-Mike-
[email protected]
On Thu, 14 Oct 2010 22:14:49 -0400, "Mike Marlow"
<[email protected]> wrote:
>[email protected] wrote:
>
>>
>> First of all, it's just too big and heavy to fit.
>
>Why so? A caliper does not have to be large.
One from a lincoln is!!!
>
>> Second it's using an
>> atom bomb to swat a fly. Third, it's too complex. Exactly haw are you
>> going to actuate it?????
>
>Too complex? On the contrary, it's very simple.
>
>> Forth, how are you going to get it out of the way to change blades?
>
>Well, one idea would be to mount it on the inside of the arbor so that it
>does not even have to be removed to replace a blade.
That's one solution I said COULD work, isn't it?
>> Fifth - How are you going to compensate for different blade
>> thicknesses - or heaven help you, a DADO blade?
>
>See above answer.
>
>> Also, single piston or dual piston?
>
>You are going out of your way to make this appear to be complicated now.
>
>> and how are you going to ensure
>> the pressure on both sides of the blade is equal, and application is
>> even..
>
>Both sides? Why both sides? For the discussion at hand, one side would be
>ample.
>
>> Push on one side of the blade more than the other and the blade
>> goes into an oscillation/wobble and you eventually break the web out
>> of the blade. Then you have a REAL safety issue!!!!!.
>
>Sure - it you push it hard enough. No need for that level of pressure
>though. Think about what forces your blade sees as you cut through a
>knarley hunk of hardwood. It sees more lateral force than would be required
>for a simple blade brake - which is the discussion at hand.
>
>>
>> Trust me - it's a BAD idea - and almost totally unworkable on so MANY
>> levels if you understand anything about how both the saw and the break
>> caliper work.
>
>Sorry Clare - cannot trust you on this point. I see it as perfectly
>workable and not subject to any of the concerns you've outlined. I do
>understand both how the saw works and how calipers work but you have not
>argued anything to make the idea impractical.
It all depends on how fast you are stopping the blade, how big a pad
you are using, what pressure you are using, etc.
I never said you could not desin a caliper type stopping device as a
convenience brake.
I DID say there is NO WAY to effectivel use an automotive caliper
(lincoln) to do the job, and I DID say dynamic braking of one type or
other would be simpler, more effective, and more reliable.
DONE
In article <[email protected]>,
-MIKE- <[email protected]> wrote:
> I haven't seen it corrode a single thing.
> (This should cue some pseudo scientific diatribe about some oil in oak,
> contained in a minuscule amout, which is technically an acid or oxidizer
> of some sort which *can* corrode *something* on planet earth.)
Oak (and a few other woods) contains tannic acid which /over time/ will
corrode ordinary steel screws. I was taught to assemble stuff made with
oak with steel screws and then replace with brass. Choice of materials or
protective coatings will nullify any problems in this instance.
In article <[email protected]>,
-MIKE- <[email protected]> wrote:
> I knew *he* would, but I didn't think anyone else would jump in.
> Have you read the thread up until this point, or even a couple posts
> preceding?
Just fulfilling your wish :-)
Corrodes the hell out of my sinuses! Usually a bloody nose the next morning
everytime, after Oak...LOL
"-MIKE-" <[email protected]> wrote in message
news:[email protected]...
And since when is Oak sawdust corrosive... no, I'm sorry..."VERY
CORROSIVE?"
I saw my fair amount of oak and I'm not exactly a neat guy in the shop.
I clean up my saw dust when it pisses me off enough, which is usually
when it's in the way of the next project, which means, it can sit around
under the saw, on my tools, all kinds of other metal, plastic, and
rubber stuff, including the end of this run-on sentence, for months at a
time.
I haven't seen it corrode a single thing.
(This should cue some pseudo scientific diatribe about some oil in oak,
contained in a minuscule amout, which is technically an acid or oxidizer
of some sort which *can* corrode *something* on planet earth.)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
<[email protected]> wrote:
>Larry Jaques wrote:
>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>
>>>
>>> As a guy who has done all of his own vehicle maintenance for 40
>>> years now, I have to ask what you observed in your experiences, that
>>> causes you to make this statement? I don't know if the brake
>>> caliper idea is the most elegant solution, but I sure can't see
>>> anything in what you are saying that would suggest it is not a
>>> workable solution.
>>
>> Suitable placement of an air nozzle tube to clear the caliper frame
>> every hour or so would go far into making this device work for more
>> than an hour. You'd have to keep the sawdust from piercing the seals
>> and/or building up on the frame
>
>Not at all Larry, if you consider what a normal brake caliper in an
>automobile is subject to. In comparison, the environment inside a table saw
>would be a walk in the part of a caliper.
I heartily disagree. The only solid ever thrown up at a brake caliper
in any quantity is water, and that runs right off. Sawdust would tend
to stick, especially in the inverted configuration it would have on a
table saw. 'Twould be especially bad with folks who "do Jummywood."
Go ahead and prove me wrong, Mike. Mount one and see. I double dare
ya!
--
Do not taunt Happy Fun Ball!
On Thu, 14 Oct 2010 08:52:30 -0400, "Mike Marlow"
<[email protected]> wrote:
>Steve Turner wrote:
>
>>
>> Another reality check for all the people taking this thread off into
>> the wild blue yonder is the issue of getting the blade onto the arbor
>> in the presence of calipers that grip either side of the blade. My
>> interest (and Mike's as well, I think) in using a bicycle brake was
>> simply a matter of "how can I retrofit my existing table saw with a
>> simple convenience brake?" I think the wide-opening jaws of a
>> bicycle brake (maybe along with some kind of front-side cable
>> disconnect to allow the calipers to drop out of the way) would allow
>> enough clearance to get the blade on the arbor without too much
>> trouble. This heavy-duty automotive caliber Saw-Stop alternative
>> that everybody else is talking about would also have to provide a
>> similar mechanism, which would of course add to the complexity.
>
>It would be quite easy to mount the caliper on a pivoting mount that would
>allow it to swing out of the way for changing blades.
Adding the necessity of an interlock switch so you could not forget
to reposition it and still run the saw ----
More complexity = less reliability.
On 10/14/2010 2:52 PM, [email protected] wrote:
> On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
> <[email protected]> wrote:
>
>> Larry Jaques wrote:
>>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>>> <[email protected]> wrote:
>>
>>>>
>>>> As a guy who has done all of his own vehicle maintenance for 40
>>>> years now, I have to ask what you observed in your experiences, that
>>>> causes you to make this statement? I don't know if the brake
>>>> caliper idea is the most elegant solution, but I sure can't see
>>>> anything in what you are saying that would suggest it is not a
>>>> workable solution.
>>>
>>> Suitable placement of an air nozzle tube to clear the caliper frame
>>> every hour or so would go far into making this device work for more
>>> than an hour. You'd have to keep the sawdust from piercing the seals
>>> and/or building up on the frame
>>
>> Not at all Larry, if you consider what a normal brake caliper in an
>> automobile is subject to. In comparison, the environment inside a table saw
>> would be a walk in the part of a caliper.
>
>
> You get a splinter of oak thrown at a rubber caliper boot at 18000
> feet per minute (almost 205MPH) a few times and expect the boot to
> survive?. For the brake to see the same rotational RPM on a car with
> 24" diameter tires (pretty standard today) you would need to drive
> over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
>
> A 10" saw runs closer to 5200 RPM - so 370 MPH.
Ever heard of "mass"? By your logic, my Dremel tool running at 30,000 RPM
would be even more impossible to stop.
> Also, the caliper is actually pretty well protected mounted as it is
> virtually inside the wheel - with the caliper boot protected between
> the pad and tha caliper frame, and usually behind a splash shield as
> well.
>
> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> onto every surface of the caliper.
Geez Chicken Little, how many mountains are you going to make out of molehills
on this topic? Just about every point you've tried to make has had the air of
doom, disaster, and failure. This ain't that friggin' difficult, Penelope.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/
On 10/14/10 4:22 PM, Steve Turner wrote:
>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>> onto every surface of the caliper.
>
> Geez Chicken Little, how many mountains are you going to make out of
> molehills on this topic? Just about every point you've tried to make has
> had the air of doom, disaster, and failure. This ain't that friggin'
> difficult, Penelope.
>
And since when is Oak sawdust corrosive... no, I'm sorry..."VERY
CORROSIVE?"
I saw my fair amount of oak and I'm not exactly a neat guy in the shop.
I clean up my saw dust when it pisses me off enough, which is usually
when it's in the way of the next project, which means, it can sit around
under the saw, on my tools, all kinds of other metal, plastic, and
rubber stuff, including the end of this run-on sentence, for months at a
time.
I haven't seen it corrode a single thing.
(This should cue some pseudo scientific diatribe about some oil in oak,
contained in a minuscule amout, which is technically an acid or oxidizer
of some sort which *can* corrode *something* on planet earth.)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/14/10 5:06 PM, Robatoy wrote:
> In article<[email protected]>,
> [email protected] wrote:
>
>>
>> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
>> onto every surface of the caliper.
>
> More corrosive than road salt?
More corrosive than brake fluid? Because calipers neeeeeever leak.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 10/15/10 6:07 PM, Stuart wrote:
> In article<[email protected]>,
> -MIKE-<[email protected]> wrote:
>
>> I haven't seen it corrode a single thing.
>> (This should cue some pseudo scientific diatribe about some oil in oak,
>> contained in a minuscule amout, which is technically an acid or oxidizer
>> of some sort which *can* corrode *something* on planet earth.)
>
> Oak (and a few other woods) contains tannic acid which /over time/ will
> corrode ordinary steel screws. I was taught to assemble stuff made with
> oak with steel screws and then replace with brass. Choice of materials or
> protective coatings will nullify any problems in this instance.
>
I knew *he* would, but I didn't think anyone else would jump in.
Have you read the thread up until this point, or even a couple posts
preceding?
Context is a wonderful thing.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On Thu, 14 Oct 2010 09:27:45 -0400, "Mike Marlow"
<[email protected]> wrote:
>Larry Jaques wrote:
>> On Thu, 14 Oct 2010 08:50:21 -0400, "Mike Marlow"
>> <[email protected]> wrote:
>
>>>
>>> As a guy who has done all of his own vehicle maintenance for 40
>>> years now, I have to ask what you observed in your experiences, that
>>> causes you to make this statement? I don't know if the brake
>>> caliper idea is the most elegant solution, but I sure can't see
>>> anything in what you are saying that would suggest it is not a
>>> workable solution.
>>
>> Suitable placement of an air nozzle tube to clear the caliper frame
>> every hour or so would go far into making this device work for more
>> than an hour. You'd have to keep the sawdust from piercing the seals
>> and/or building up on the frame
>
>Not at all Larry, if you consider what a normal brake caliper in an
>automobile is subject to. In comparison, the environment inside a table saw
>would be a walk in the part of a caliper.
You get a splinter of oak thrown at a rubber caliper boot at 18000
feet per minute (almost 205MPH) a few times and expect the boot to
survive?. For the brake to see the same rotational RPM on a car with
24" diameter tires (pretty standard today) you would need to drive
over 250 MPH. Closer to 260MPH if the saw runs 3650 RPM.
A 10" saw runs closer to 5200 RPM - so 370 MPH.
Also, the caliper is actually pretty well protected mounted as it is
virtually inside the wheel - with the caliper boot protected between
the pad and tha caliper frame, and usually behind a splash shield as
well.
Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
onto every surface of the caliper.
In article <[email protected]>,
[email protected] wrote:
>
> Then start sawing oak, and leaving the VERY CORROSIVE sawdust caked
> onto every surface of the caliper.
More corrosive than road salt?
On Sun, 10 Oct 2010 11:54:19 -0500, -MIKE- <[email protected]>
wrote:
>On 10/10/10 11:35 AM, willshak wrote:
>> WW wrote the following:
>>> "HeyBub" <[email protected]> wrote in message
>>> news:[email protected]...
>>>> Found this article...
>>>>
>>>> "Single-phase induction motors drive many arbor-mounted cutting tools
>>>> in the home workshop. Stationary grinders, table and radial arm
>>>> circular saws frequently turn abrasive or cutting disks that are
>>>> directly mounted on the motor's spindle. These disks have large
>>>> inertial moments that allow them to free wheel for a long time after
>>>> the power is turned off. A lengthy coast to complete stop often
>>>> amounts to a major inconvenience."
>>>>
>>>> http://www.homemetalshopclub.org/news/sep01/sep01.html#reversing
>>>>
>>>>
>>>> Great ... I may rig up my table saw this way. Would be safer with a
>>>> brake. WW
>>
>> If I need to stop a spinning table saw blade in a hurry to change or
>> reset something, I find that a scrap piece of lumber makes a great blade
>> brake. Turn the saw off and slide the scrap up to the still spinning
>> blade. Blade stops in a couple of seconds. No extra parts needed.
>>
>
>Someone could make some money by developing an aftermarket saw brake,
>under the table.... pads or rollers or whatever, that would squeeze the
>blade.
Lawsuits from the arse with the SawStop patents notwithstanding, I
think he went with the positive stop style because it's the only one
which would keep from taking a finger off. The rest spin just enough
to do serious damage.
--
Ask not what the world needs. Ask what makes you come
alive... then go do it. Because what the world needs
is people who have come alive. -- Howard Thurman
I doubt most people use a pusher stick to cut plywood sheets.
Now we have to define "close"...LOL
"Steve Turner" <[email protected]> wrote in message
news:[email protected]...
Would I be correct in assuming you were pushing the wood into the blade with
your bare hands rather than using a push jig or Gripper or something
similar?
On 10/12/2010 9:19 PM, Hoosierpopi wrote:
> On Oct 12, 12:21 pm, Steve Turner<[email protected]>
> wrote:
>
> wildly advancing your fingers towards the blade,
>
> As is done when, say, you are pushing a bit of wood into the saw and
> it jerks out of place and you essentially "fall" forward now that the
> wood is no longer offering resistance?
I've read that about five times and have tried to visualize what you're
talking
about, but I'm still puzzled.
> Of course, the blade never stop turning at all on the saw I was using,
> but I did manage to put three finges and a thumb in its path before
> realizing I was cutting skin and bone - and jerked back.
>
> Only cut clean through one digit and got it sewed and screwed back
> on.
--
See Nad. See Nad go. Go Nad!
To reply, eat the taco.
http://www.flickr.com/photos/bbqboyee/