RE: T/S Inertia

> Toss a dirty sock into the blade and it stops faster than a
> washing machine.

How do you know this? LOL.

Sonny

"Lobby Dosser" <[email protected]> wrote

> Which tools should have, as they cannot start if they were shut down due
> to a power failure and the power is restored. No foul if the TV comes back
> on, but power tools are a whole other story.

Have you ever seen the extension cord type device that is sold for tools
without magnetic starters to guard against exactly the thing you just
mentioned?

If not, or for those unaware, it is a section of cord with a box with a
brain inline that allows a tool with a regular mechanical switch to operate
normally, until the power to the tool is interupted, either by the plug
getting bumped, the main power cutting out, or a tripped breaker or fault
protector. At that point, even if the power is out only for an instant, the
tool will not be given power back by the brain box, until a reset button on
the brain it pressed.

Not nearly as expensive as magnetic starters, easy to use, and give another
layer of safety. Plus, it satisfies the requirements that may apply to a
shop that is inspected by OSHA or insurance inspectors. Some products are
GFCI's that require pressing the reset button before it will come back on
after power is interupted, and some only mimic a magnetic starter. Seems as
though it was in the mid 30 dollar price range, when I looked at them a
couple years ago.
--
Jim in NC

On Aug 7, 11:22=A0pm, "HeyBub" <[email protected]> wrote:
> [email protected] wrote:
> > On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
> > <[email protected]> wrote:
>
> >> I have been taking a basic wood working at a local community college.
>
> >> As you would expect, there is a heavy emphasis on safety.
>
> >> They have a collection of table saws including General, Delta Unisaw
> >> and PM66.
>
> >> Over the years there have been a few T/S accidents.
>
> >> Analyzing these accidents revealed the following:
>
> >> 1) The majority of accidents involved the PM66.
>
> >> 2) After shutting off, the PM66 required 20-30 seconds more to come
> >> to a rest than either the General or Unisaw.
>
> >> Looking at the saw blade, it was very difficult to see if the blade
> >> was still spinning.
>
> > The only time I've ever come close to getting bitten by my Unisaw was
> > exactly this. =A0A blade brake would be a great addition to any table
> > saw.
>
> Some years ago, the federal government, in its infinite wisdom, and all t=
he
> while thinking of the children, mandated that washing machines come to a
> complete stop in just a few seconds (like three).
>
> It shouldn't be hard to transfer that technology to table saws.- Hide quo=
ted text -
>
> - Show quoted text -

Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.

On Aug 9, 11:22=A0am, "[email protected]" <[email protected]> wrote:
> On Aug 9, 9:36=A0am, Robatoy <[email protected]> wrote:
>
>
>
>
>
> > On Aug 9, 12:41=A0am, "Lobby Dosser" <[email protected]> wrote:
>
> > > "Larry W" <[email protected]> wrote in message
>
> > >news:[email protected]...
>
> > > > In article <[email protected]>,
> > > > Mike Marlow <[email protected]> wrote:
> > > > <...snipped...>
> > > >>Nah - don't need sawstop for this need Leon. =A0A simple brake is a=
ll that
> > > >>is
> > > >>necessary. =A0With all of the chop saws that come with brakes today=
, it
> > > >>really
> > > >>should be no big deal for a table saw to have the same capability -=
it's
> > > >>been around forever.
>
> > > >>--
>
> > > > I agree with that: I've seen brake setups on industrial machinery p=
owered
> > > > by 150 HP motors, geared down to about 30 RPM turning a roller that
> > > > weighed
> > > > a few tons, that could stop the roller in less than a 1/4 turn. I d=
on't
> > > > see
> > > > why any sacrificial parts are necessary for a saw to do what the sa=
wstop
> > > > does. If Delta, Jet, etc. wanted to spend a little R&D money, they
> > > > could build a safer saw that was _better_ than sawstop.
>
> > > The claim to fame for SawStop is Not stopping the blade, but Sensing =
when
> > > your pinkie finger touched the blade and Then stopping the blade befo=
re you
> > > lose said pinkie.
>
> > I just installed a new high-tech toilet. (For real) It has a dampening
> > mechanism for lowering the seat. I will be designing a logo in a
> > similar vein as Sawstop and call it LopStop. The days of having a seat
> > slam on one's schlong are over.
>
> How cold is the water?

LOL

On Mon, 9 Aug 2010 08:48:54 -0400, "Josepi" <[email protected]> wrote:

>Not true.
>
>I worked with many different dynamic and mechanical braking systems,
>including DC Injection braking and none were any special motors. OTOH these
>were industrial applications using larger HP units.
>
>Geeeeez. My cheap $189 slide saw has dynamic braking on it and I doubt it is
>any special motor. The blade had to worth half the price. It also has a
>delay circuit that doesn't react immediately.

That's why I'm surprised higher end table saws don't use dynamic braking. The
controller is a lot more complicated (expensive) than a slider's. It doesn't
seem like much of a stretch to add a couple of contacts to it.

This is better with some resistance to absorb the energy. Without it the
switch contacts usually burn off, quickly.


"Father Haskell" <[email protected]> wrote in message
news:02510f27-22e4-4de7-afca-Electric brake -- short out the supply wires
after cutting the power,
and the motor forces itself to stop.

"HeyBub" <[email protected]> wrote

> Lobby Dosser wrote:
>>
>> None of these saws have blade guards?
>
> Sure. All new saws come with blade guards and the guards receive about as
> much attention as the sixteen-page safety manuals that also accompany a
> new saw.
>
> Like the safety manuals, the blade guards are included with a new saw for
> the company's benefit, not the consumers'.

It seem so me that one reason why people discard the crown guard (hood,
Murricans) is the following ( http://tinyurl.com/382fe4c )

1910.213(c)(1)

'The hood and mounting shall be arranged so that the hood will automatically
adjust itself to the thickness of and remain in contact with the material
being cut but it shall not offer any considerable resistance to insertion of
material to saw or to passage of the material being sawed.'

Of the few I've tried, this is darned near impossible to get the hood to
automatically be elevated by the leading edge of the job if one is sawing
material of varying thicknesses, so it is not surprising that people get fed
up with them.

There's a pic of an ideal(?) but darned expensive and difficult-to-fit guard
at the foot of http://tinyurl.com/pywalm

Jeff

--
Jeff Gorman, West Yorkshire, UK
email : Username is amgron
ISP is clara.co.uk
www.amgron.clara.net

On Sat, 7 Aug 2010 20:46:57 -0700, "Lew Hodgett" <[email protected]>
wrote:

>
>"Nonnymus" wrote:
>
>> Strange, I had a PM66 and didn't feel it took that long to coast
>> down. I'm not disagreeing- just commenting. It sure was a great
>> saw and once adjusted with the TS Aligner, it stayed that way.
>-------------------------------
>If your saw is a stand alone device, you become aclimated to it;
>however, if you have a shop with a PM66 AND say a Unisaw, it could be
>a problem.
>---------------------------------
>>> Never used a Unifence, so can't say whether I'd like it better or
>>> not.
>>> Why?
>--------------------------------------
>1) No need for a separate stop block and clamp.

Explain please.

>2) Can quickly move fence to either side of the blade as req'd.

Huh? The Beisemeyer moves pretty quickly.

>3) If you mount a 1.5" thick sacrifical fence, you can use existing
>calibrated tape measure directly without making a separate
>calibration.

Ok. I don't use the tape measure. I have one of the Wixey gauges, and still
check it off a tooth.

"Lobby Dosser" <[email protected]> wrote

>> Have you ever seen the extension cord type device that is sold for tools
>> without magnetic starters to guard against exactly the thing you just
>> mentioned?
>
> Thanks, good to know and I'll google it as soon as I can think of what to
> search for.

Oh, I think I would stick with the GFCE with a manual reset, for this price.
http://www.grainger.com/Grainger/UL-Restart-Protection-Cord-3KUZ7?Pid=search

I sent a reply to the poster, instead of the group earlier by mistake. Here
is that message with a link.

found this brand, but I think they are all GFCI's, too. I have found that
using a GFCI on top of a GFCI protected like can sometimes lead to excessive
false resets.

I will keep looking for a little while, but there is one type. Just find a
dealer and you are all set.

I forgot the link the first time.
http://tools.passandseymour.com/psgfci/downloads/PortableGFCI_bro.pdf
--
Jim in NC

"Morgans" <[email protected]> wrote in message
news:[email protected]...
>
> "Leon" <[email protected]> wrote >
>>
>> That would be the desired effect but with a contractors saw I would be
>> shocked if the motor stopped and the blade did not continue to spin a few
>> times.
>
> I don't know what drive system contractor saws use. I know the Craftsman
> my Dad had, used a toothed belt, so if the motor stopped, the blade would
> stop, at least until it tore the teeth off the belt. I think some use a
> gear drive, don't they?
> --
> Jim in NC
>

Toothed belt,, as in like a timing belt? or a standard automotive belt?
Normal drive belts with the notches cut out are made that way so that they
can turn a tigher radius. Those normally have no more grip than a belt with
out a notches cut out. A timing style belt with equal sized spaced, and
shallower notches are designed for absolutely no slip.

Some saws are actually direct drive and bench top saws are typically gear
reductions.

On Aug 8, 3:10=A0pm, "Josepi" <[email protected]> wrote:
> Years ago I was attempting to create a CD rack (bored) using an old 3/4"
> piece =A0of oak. I was going to dado some exact width slots in it for the=
CD's
> to stand up and tilt in, using a table mounted router.
>
> After about the third or fourth dado slot I found the router bit came rig=
ht
> up through the top (backside) of the piece. The router depth locking scre=
w
> came loose (or I forgot to tighten it) and the vibration from the table m=
ade
> the router gear rack screw itself right up through the 3/4" depth of the
> wood instead on holding a 3/8" depth slot. I never figured that was possi=
ble
> until I was staring at the 30K RPM bit by my fingers.
>
> Wasted piece of wood (made it shorter) but the lesson was a good one
> learned. Nobody got hurt but I never (If I ever did?) put my hands over t=
op
> of the router bit, anymore, no matter how thick the piece is. Pusher stic=
ks
> and distance became paramount.

That's an oddball one. I would have figured the weight of the router
would have caused the whole shebang to drop, not rise. I could see a
loose collet causing the bit to rise. Either way, it's like Sancho
Panza said, "Whether the rock hits the pitcher, or the pitcher hits
the rock, it's bad for the pitcher."

R

"Nonnymus" wrote:

> Strange, I had a PM66 and didn't feel it took that long to coast
> down. I'm not disagreeing- just commenting. It sure was a great
> saw and once adjusted with the TS Aligner, it stayed that way.
-------------------------------
If your saw is a stand alone device, you become aclimated to it;
however, if you have a shop with a PM66 AND say a Unisaw, it could be
a problem.
---------------------------------
>> Never used a Unifence, so can't say whether I'd like it better or
>> not.
>> Why?
--------------------------------------
1) No need for a separate stop block and clamp.
2) Can quickly move fence to either side of the blade as req'd.
3) If you mount a 1.5" thick sacrifical fence, you can use existing
calibrated tape measure directly without making a separate
calibration.

Lew


>
> Nonny

"CW" wrote:
> Last shop I worked in (that I used a tablesaw), there was a rule
> that when you turned it off, you cranked the blade down below table
> height.
---------------------------------
Good rule.

Lew

"Lobby Dosser" wrote:

> None of these saws have blade guards?
--------------------------------------
None are equipped with guards, all are equipped with a removable
splitter, zero clearance plates and a 2P-30A, non-fused disconnect.

Standard procedure is to leave saw in the blade down position and the
disconnect in the "OFF" position.

Also the disconnect is in the "OFF" if you are even going to think
about removing the throat plate to change blades, install dado,
remove/replace splitter, etc.

Did not have a disconnect on my personal saw; however, did have a plug
and receptacle the served the same function.

NEVER trust just a switch, sooner or later it will bite you.

A visible disconnect is your friend.



Lew

"Morgans" <[email protected]> wrote in
news:[email protected]:

> You know, I used to be about like anyone else, in that I never used a
> guard
> on a table saw. That all changed 18 years ago, when I took a job
> teaching carpentry at the local high school. It was made very clear
> to me that any and all safety devices available were to be used, at
> all times.
>
> For the first year or so I fussed under my breath, any time I had to
> run the table saw with the guard in place. Slowly, I began to realize
> that they really were not all that bad, in nearly all cases.
>
> Now, I seldom think a second thought about the guards. The obvious
> exception is when using a tenion jig, or dado blade or other or other
> cuts that do not go all the way through the workpiece. Even then,
> there are guards available for the second class of cuts mentioned
> above.
>
> So really, if everyone just made up their mind to keep with a guard
> until they got used to it, you would find that it is a rare case where
> the guard slows them down or prevents accurate cutting.

I think a lot of the problem is home table saw guards aren't good enough.
The first table saw I had was a Craftsman entry-level saw, and the guard
did not align with the saw blade at all. My current saw is a Ridgid, and
the guard takes a few minutes to adjust to be behind the blade exactly,
and has to be removed to allow trimming 1/8"-1/4" off one side to get a
decent edge.

There's better mounting mechanisms (behind the blade on the blade height
riser [riving knife style]) and new guard designs to allow trimming cuts
(each side of the guard moves independently) but I haven't used either of
them yet to say if they're really better.

Puckdropper
--
Never teach your apprentice everything you know.

"RonB" <[email protected]> wrote

>Agree - As the original poster noted most good schools press safety.
>We will have more folks starting off with little if any training.

>Ron

With less emphasis on safety. Shame

Max

The only problem I have with all these safety devices is that, in my
experience with the Fire Department, they do tend to have unintended
consequences; that being that people tend to be less concious of safety.
The government can only do so much to require things to be foolproof.
There really is no such thing.
My wife's car tells the driver when the lights are left on, to fasten a seat
belt, if a door is ajar, if the trunk lid or hood is open, if the fuel level
is low,
and probably several other things that I've not yet had the occasion to
experience. And I'm not even going to tell you about the GPS!!
It's enough to give me an inferiority complex.

Max

"dpb" wrote:

> From first posting I see in this thread...
>
>> I have been taking a basic wood working at a local community
>> college.
>>
>> As you would expect, there is a heavy emphasis on safety.
>
> Those two don't correlate.
---------------------------------------
They do if you include the rest of the T/S instruction which includes
hand placement, use of push blocks, standing location when starting to
feed stock for cutting, how to finish cut with hands in a clear
position which includes insuring the saved piece clears the back of
the table (Yes, a run out table is req'd).

Basically, insure that you stay away from the blade when it is above
the table top.

Lew

"Lobby Dosser" wrote:

> Which we can safely discount as being 100% successful. I too wonder
> about their insurance. Perhaps you can ask them.
---------------------------

They put an average of 500 students per year thru WMT101 (Basic req'd
course to take any advanced courses) which in and of itself is quite a
statement.

The lawyers and the insurance gods have long ago put holy water on
this program which just gets bigger every year.

Lew

"Father Haskell" wrote:

>Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.
--------------------------------------
Two totally different things.

One is a disc brake that immediately clamps when power is removed and
when stopped, holds the shaft in place.

The other is what is called dynamic braking.

Involves an electro/mechanical interlocked reversing motor starter
with the reversing contactor contacts shorted together with a heavy
duty bus bar.

The spinning rotor generates the back EMF and stops the motor, but
does not lock the shaft in place.

You need a well made motor because of the very high mechanical
stresses imposed on the stator.

Both are expensive, even for heavy duty machine tool applications.

Lew

"Lobby Dosser" wrote:

> Why do the lawyers and insurance folks deem it good?
----------------------------------------
I'm reminded of an old time baseball player named "Wee Willy Keeler"
who when asked why he was such a successful hitter responded, "..
cause I hit em where they ain't.

The course is built around prevention.

If you don't stay focused, "SHIT HAPPENS", so address it head on.

How you address the saw.(Where do you stand and how?)

How you set the blade height for the task at hand.

Is the splitter /W/ pawls properly installed to prevent kick back?

Where do you place your hands to keep the stock down on the table and
against the fence?

Are your eyes focused on the fence to insure the stock stays in
contact with the fence?

Has your left hand been placed behind your back at the proper time?

Is the correct push stick in the right location and readily available,
if req'd?

The list goes on, but the idea is to train your body to perform SAFE
motions in the proper sequence almost automatically. Think "Wax On,
"Wax Off".

.
Lew


.

<[email protected]> wrote in message
news:[email protected]...
> On Mon, 09 Aug 2010 18:37:26 -0500, Steve Turner
> <[email protected]> wrote:
>
>>On 8/9/2010 5:20 PM, [email protected] wrote:
>>> On Sun, 8 Aug 2010 19:43:12 -0500, "Leon"<[email protected]>
>>> wrote:
>>>
>>>>
>>>> <[email protected]> wrote in message
>>>> news:[email protected]...
>>>>> On Sat, 7 Aug 2010 20:46:57 -0700, "Lew
>>>>> Hodgett"<[email protected]>
>>>>> wrote:
>>>>>
>>>>>>
>>>>>> "Nonnymus" wrote:
>>>>>>
>>>>>>> Strange, I had a PM66 and didn't feel it took that long to coast
>>>>>>> down. I'm not disagreeing- just commenting. It sure was a great
>>>>>>> saw and once adjusted with the TS Aligner, it stayed that way.
>>>>>> -------------------------------
>>>>>> If your saw is a stand alone device, you become aclimated to it;
>>>>>> however, if you have a shop with a PM66 AND say a Unisaw, it could be
>>>>>> a problem.
>>>>>> ---------------------------------
>>>>>>>> Never used a Unifence, so can't say whether I'd like it better or
>>>>>>>> not.
>>>>>>>> Why?
>>>>>> --------------------------------------
>>>>>> 1) No need for a separate stop block and clamp.
>>>>>
>>>>> Explain please.
>>>>
>>>> Take a look at one to understand what I am about to explain. ;~)
>>>
>>> No gots.
>>>
>>>> The
>>>> Unifence fence slides left, right, forward, and backward. Because you
>>>> can
>>>> slide it backwards the end near the back of the saw table can be
>>>> situated in
>>>> front of the blade.
>>>
>>> Oh, that makes perfect sense.<sheesh>
>>
>>The fence is an extruded aluminum channel that attaches to the carrier
>>with
>>bolts secured by large wing nuts. By simply loosening the wing nuts you
>>can
>>adjust the fence towards you or away from you. This is very handy when
>>you
>>need to cross-cut something with the miter gauge; slide the fence towards
>>you
>>so that the far end is in front of the blade (prevents the cutoff from
>>being
>>trapped between the fence and the blade), use the fence scale to set the
>>cutoff
>>distance, register the end of the workpiece against the fence, then push
>>through the blade with the miter gauge.
>>
>>More clearer?
>
> Much better. Thanks.
>
> Sounds like it's a bitch keep aligned.

Not mine. I check it before any significant project and It very rarely needs
any adjusting.
Why would it?

Max

"[email protected]" <[email protected]> wrote in
news:[email protected]:
>
> That's why I'm surprised higher end table saws don't use dynamic
> braking. The controller is a lot more complicated (expensive) than a
> slider's. It doesn't seem like much of a stretch to add a couple of
> contacts to it.

As a side benefit, you can put the generated energy back in the grid and
recoup some of the electric cost of running the saw. *grin*

Puckdropper
--
Never teach your apprentice everything you know.

"Morgans" <[email protected]> wrote in message
news:[email protected]...
>
> <[email protected]> wrote
>
>> Aluminum. Wingnuts. Sliding. All these things scream "alignment" to me.
>>
> Not really. The aluminum part that moves is up against the heavy casting
> that is the part that securely locks to the saw. Once you have the
> casting set, the aluminum repeats accurately (it is metal on metal with
> nothing to let it become inaccurate) when it is tightened against the
> casting.
>
> I usually keep mine accuratly adjusted to under a 32nd of an inch, and it
> stays there for a long period of time. It takes something hitting it
> really hard to knock it out of adjustment.
>
> I don't understand people that get out a tape measure to check their
> setting for every single cut. I set up my machine and scale to cut what I
> set it on, and go to town. If I really need a super accurate cut, I check
> the setting with a trial cut on a scrap. It is nearly always what I had
> the scale set on.
> --
> Jim in NC

What he said but 1/32 of an inch is not close enough for me.
Tape measure? ACK! I use a dial gauge *very* rarely but I have a rule
that's marked in 64ths and I expect the fence to be *on the money*.

Max

"Morgans" <[email protected]> wrote in
news:[email protected]:

*snip*

> I don't understand people that get out a tape measure to check their
> setting for every single cut. I set up my machine and scale to cut
> what I set it on, and go to town. If I really need a super accurate
> cut, I check the setting with a trial cut on a scrap. It is nearly
> always what I had the scale set on.

I don't trust my fence indicator. I had it set correctly once, but as
the saw got moved around, the rails (where the indicator is) on the saw
moved as well. It's so much easier to get the tape out and adjust the
fence than to try to keep the indicator reading true.

Puckdropper
--
Never teach your apprentice everything you know.

"Jeff Gorman" wrote:

> For an almost instant stop, I gather that something called DC
> injection is required and this requires a special and expensive
> motor.
----------------------------------
My previous post INCORRECTLY described "Regenerative braking" as
"Dynamic braking".

Dynamic braking still requires a set of interlocked contactors which
very much look like a reversing motor starter which is used to apply a
DC voltage to the motor windings.

You need a DC power supply and a time delay relay to accomplish
dynamic braking.

Take your choice, a motor mounted disc brake, a regenerative braking
or a dynamic braking approach.

All are expensive, have lots of control hardware and are used on 3
phase motors.

It is totally cost prohibitive for a single phase motor.

Lew

"Jack Stein" <[email protected]> wrote in message
news:[email protected]...
> Lew Hodgett wrote:
>
>> Also the disconnect is in the "OFF" if you are even going to think about
>> removing the throat plate to change blades, install dado, remove/replace
>> splitter, etc.
>
>> Did not have a disconnect on my personal saw; however, did have a plug
>> and receptacle the served the same function.
>>
>> NEVER trust just a switch, sooner or later it will bite you.
>
> All I do is turn off the saw. I was making up a railing for a friend just
> yesterday and putting on the dado blade. He said don't you pull the
> cord... I don't. Never saw a light, appliance or power tool go on by
> itself. He said what if someone turns in on by accident? I said that
> would have to be me, and if I'm that freaking dumb, I deserve to lose an
> arm. I'm sure a switch has gone on by itself at least once somewhere, but
> in well over half a million hours of experience, I've not witnessed it, I
> asked him if he ever witnessed same, he said no, so thats well over one
> million hours of testing... so I live on the edge...
>
> Geez, no guard, no splitter, no disconnect... Thrill a minute...

>Jack.

Keeps life interesting.

Max

Jack Stein <[email protected]> wrote in
news:[email protected]:


> All I do is turn off the saw. I was making up a railing for a friend
> just yesterday and putting on the dado blade. He said don't you pull
> the cord... I don't. Never saw a light, appliance or power tool go on
> by itself. He said what if someone turns in on by accident? I said
> that would have to be me, and if I'm that freaking dumb, I deserve to
> lose an arm. I'm sure a switch has gone on by itself at least once
> somewhere, but in well over half a million hours of experience, I've
> not witnessed it, I asked him if he ever witnessed same, he said no,
> so thats well over one million hours of testing... so I live on the
> edge...
>
> Geez, no guard, no splitter, no disconnect... Thrill a minute...
>

I've seen some things turn on by themselves, or more likely *not* turn
on. Usually what happened is the switch is either not in a full off
position or defective. The switch not being in a full off position is
difficult on most of the power tools I've used.

Now some of these modern computers... Those stupid things turn on when
power is connected.

Puckdropper
--
Never teach your apprentice everything you know.

"Morgans" wrote:


> Oh, I think I would stick with the GFCE with a manual reset, for
> this price.
> http://www.grainger.com/Grainger/UL-Restart-Protection-Cord-3KUZ7?Pid=search
----------------------------------------
If you are going to spend that kind of money might just as well do it
right and get a NEMA Size 1, 1PH motor starter complete with a NEMA 1
enclosure and a remote Start-Stop push button station.

The above will handle a 3HP,1 PH,60 HZ motor operating at 230VAC.

Haven't sold motor controls for almost 30 years so have lost all cost
data; however, WW Grainger is not known for giving away the store.

I'd check a local industrial electrical distributor.

Lew

"Lobby Dosser" <[email protected]> wrote

> Pass and Seymour offer Manual Reset models, so probably the same price as
> Grainger. I think I'll just remember to unplug!


The local (El Paso) Lowes has them.

http://tinyurl.com/2vcnlt4

Max

"Morgans" wrote:

> That is why I said the kind with the GFCI and a manual reset (you
> did not copy that link) is more reasonable. You could not get a
> starter and station and other required hardware for that price.
>
> That product is listed here:
>
> http://tools.passandseymour.com/psgfci/downloads/PortableGFCI_bro.pdf
>
> I found it somewhere for about 36 bucks; includes a aigtail male and
> female, with a box containing the GFCI in the middle. Available for
> 15 and 18 amp -120 volt and also 240 volt.

-------------------------------
In it's wildest wet dream, it doesn't begin to provide the function
and protection of a motor starter.

Lew

On Aug 8, 3:43=A0pm, RonB <[email protected]> wrote:
>
> Watch what happens if the SawStop technology is forced on high school
> and smaller tech schools. =A0Our high school just dropped the
> woodworking program because the lawyer told them to add SawStop
> technology or close the program. =A0They had finally upgraded to a
> couple of new Powermatics after nearly 30 years with now worn out
> Unisaws. =A0Couldn't afford to upgrade again so they sold the shop off.

SawStop is a game changer, no doubt about that. Losing high school
shop programs is totally unacceptable. My HS sucked - we didn't have
any shop programs at all. I used to drool over the things my older
brother would bring back from shop class at his high school. I wonder
sometimes how different my life would be if there had been a wood
shop. Maybe nothing would have changed, I don't know. Maybe I would
just have had better training and several more years of experience.

R

"Morgans" <[email protected]> wrote in message
news:[email protected]...
>
> "Lobby Dosser" <[email protected]> wrote
>>
>> It turns off when the grid power goes off. When the power returns, the
>> device does not start until the switch is pressed.
>
> As does the right portable GFIC device.
> --
> Jim in NC
>

What does GFIC stand for? Not confusing with GFCI I presume as those do not
have to be reset after a power failure.

On Aug 13, 5:53=A0am, "J. Clarke" <[email protected]> wrote:
> On 8/13/2010 12:43 AM, Lew Hodgett wrote:
>
>
>
> > "Morgans" wrote:
>
> >> That is why I said the kind with the GFCI and a manual reset (you
> >> did not copy that link) is more reasonable. =A0You could not get a
> >> starter and station and other required hardware for that price.
>
> >> That product is listed here:
>
> >>http://tools.passandseymour.com/psgfci/downloads/PortableGFCI_bro.pdf
>
> >> I found it somewhere for about 36 bucks; includes a aigtail male and
> >> female, with a box containing the GFCI in the middle. =A0Available for
> >> 15 and 18 amp -120 volt and also 240 volt.
>
> > -------------------------------
> > In it's wildest wet dream, it doesn't begin to provide the function
> > and protection of a motor starter.
>
> So what wonderful magical thing does =A0a motor starter do that makes it
> so vastly more functional and protective?

Low voltage drop-out?

Leon wrote:
> "HeyBub" <[email protected]> wrote in message
> news:[email protected]...
>
>>>
>>
>> Some years ago, the federal government, in its infinite wisdom, and
>> all the while thinking of the children, mandated that washing
>> machines come to a complete stop in just a few seconds (like three).
>>
>> It shouldn't be hard to transfer that technology to table saws.
>
>
> Sawstop

Nah - don't need sawstop for this need Leon. A simple brake is all that is
necessary. With all of the chop saws that come with brakes today, it really
should be no big deal for a table saw to have the same capability - it's
been around forever.

--

-Mike-
[email protected]

"Sonny" <[email protected]> wrote in message
news:[email protected]...
>> Toss a dirty sock into the blade and it stops faster than a
>> washing machine.
>
> How do you know this? LOL.
>
> Sonny

Sorry, that is confidential information by the R & D department.

On Sat, 7 Aug 2010 21:35:10 -0700, "CW" <[email protected]> wrote:

>
>"HeyBub" <[email protected]> wrote in message
>news:[email protected]...
>> [email protected] wrote:
>>> On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
>>> <[email protected]> wrote:
>>>
>>>> I have been taking a basic wood working at a local community college.
>>>>
>>>> As you would expect, there is a heavy emphasis on safety.
>>>>
>>>> They have a collection of table saws including General, Delta Unisaw
>>>> and PM66.
>>>>
>>>> Over the years there have been a few T/S accidents.
>>>>
>>>> Analyzing these accidents revealed the following:
>>>>
>>>> 1) The majority of accidents involved the PM66.
>>>>
>>>> 2) After shutting off, the PM66 required 20-30 seconds more to come
>>>> to a rest than either the General or Unisaw.
>>>>
>>>> Looking at the saw blade, it was very difficult to see if the blade
>>>> was still spinning.
>>>
>>> The only time I've ever come close to getting bitten by my Unisaw was
>>> exactly this. A blade brake would be a great addition to any table
>>> saw.
>>>
>>
>> Some years ago, the federal government, in its infinite wisdom, and all
>> the while thinking of the children, mandated that washing machines come to
>> a complete stop in just a few seconds (like three).
>>
>> It shouldn't be hard to transfer that technology to table saws.
>>
>
>My Hitachi has a brake. Last shop I worked in (that I used a tablesaw),
>there was a rule that when you turned it off, you cranked the blade down
>below table height. Not always possible but could do so most of the time.

Musta been one PITA for dado cuts. ;-)

On Aug 9, 12:41=A0am, "Lobby Dosser" <[email protected]> wrote:
> "Larry W" <[email protected]> wrote in message
>
> news:[email protected]...
>
>
>
>
>
> > In article <[email protected]>,
> > Mike Marlow <[email protected]> wrote:
> > <...snipped...>
> >>Nah - don't need sawstop for this need Leon. =A0A simple brake is all t=
hat
> >>is
> >>necessary. =A0With all of the chop saws that come with brakes today, it
> >>really
> >>should be no big deal for a table saw to have the same capability - it'=
s
> >>been around forever.
>
> >>--
>
> > I agree with that: I've seen brake setups on industrial machinery power=
ed
> > by 150 HP motors, geared down to about 30 RPM turning a roller that
> > weighed
> > a few tons, that could stop the roller in less than a 1/4 turn. I don't
> > see
> > why any sacrificial parts are necessary for a saw to do what the sawsto=
p
> > does. If Delta, Jet, etc. wanted to spend a little R&D money, they
> > could build a safer saw that was _better_ than sawstop.
>
> The claim to fame for SawStop is Not stopping the blade, but Sensing when
> your pinkie finger touched the blade and Then stopping the blade before y=
ou
> lose said pinkie.

I just installed a new high-tech toilet. (For real) It has a dampening
mechanism for lowering the seat. I will be designing a logo in a
similar vein as Sawstop and call it LopStop. The days of having a seat
slam on one's schlong are over.

Lobby Dosser wrote:

>
> The claim to fame for SawStop is Not stopping the blade, but Sensing
> when your pinkie finger touched the blade and Then stopping the blade
> before you lose said pinkie.

Correct - that's why I say that SawStop is not necessary for the original
problem - that being the blade taking a long time to spin down when shut
off.

--

-Mike-
[email protected]

Morgans wrote:

>
> Yes I meant to type GFCI, but fumbled.

Donchya know ya can't get away with that?...

>
> Most garden variety GFCI do not have to be reset manually after a
> power failure. Some manufacturers have designed the circuit so that
> they have to be manually reset when the power is withdrawn from the
> device. I don't know which brands, but if you read up on it a little
> bit, you will see that is the case.
>
> That could be the reason why the garden variety automatic resetting
> ones that most people have in their garages and kitchens and
> bathrooms cost about 12 bucks, but the ones meant for use in
> construction as a restart protection device cost about 36 bucks.
>

Of course - I didn't read everything through completely before replying.
I'll go sit in the corner for a short time. Point taken.

--

-Mike-
[email protected]

On Aug 9, 11:30=A0am, "Leon" <[email protected]> wrote:
> "Lobby Dosser" <[email protected]> wrote in message
>
> news:[email protected]...
>
> > "Larry W" <[email protected]> wrote in message
> >news:[email protected]...
>
> > The claim to fame for SawStop is Not stopping the blade, but Sensing wh=
en
> > your pinkie finger touched the blade and Then stopping the blade before
> > you lose said pinkie.
>
> Can't agree, that technology had been around for many years. =A0I have la=
mps
> in my house that turn off when touched, building elevator buttons that
> select by touch, and my I-phone needs the touch of skin, not a stylus or
> finger nail to work.
>
> Getting a blade spinning in excess of 3000 rpm to stop in a small fractio=
n
> of a turn and drop below the table surface is the tricky part.

No, getting around the SawStop patent is the tricky part.

On Mon, 9 Aug 2010 18:08:59 -0600, "Max" <[email protected]> wrote:

><[email protected]> wrote in message
>news:[email protected]...
>> On Mon, 09 Aug 2010 18:37:26 -0500, Steve Turner
>> <[email protected]> wrote:
>>
>>>On 8/9/2010 5:20 PM, [email protected] wrote:
>>>> On Sun, 8 Aug 2010 19:43:12 -0500, "Leon"<[email protected]>
>>>> wrote:
>>>>
>>>>>
>>>>> <[email protected]> wrote in message
>>>>> news:[email protected]...
>>>>>> On Sat, 7 Aug 2010 20:46:57 -0700, "Lew
>>>>>> Hodgett"<[email protected]>
>>>>>> wrote:
>>>>>>
>>>>>>>
>>>>>>> "Nonnymus" wrote:
>>>>>>>
>>>>>>>> Strange, I had a PM66 and didn't feel it took that long to coast
>>>>>>>> down. I'm not disagreeing- just commenting. It sure was a great
>>>>>>>> saw and once adjusted with the TS Aligner, it stayed that way.
>>>>>>> -------------------------------
>>>>>>> If your saw is a stand alone device, you become aclimated to it;
>>>>>>> however, if you have a shop with a PM66 AND say a Unisaw, it could be
>>>>>>> a problem.
>>>>>>> ---------------------------------
>>>>>>>>> Never used a Unifence, so can't say whether I'd like it better or
>>>>>>>>> not.
>>>>>>>>> Why?
>>>>>>> --------------------------------------
>>>>>>> 1) No need for a separate stop block and clamp.
>>>>>>
>>>>>> Explain please.
>>>>>
>>>>> Take a look at one to understand what I am about to explain. ;~)
>>>>
>>>> No gots.
>>>>
>>>>> The
>>>>> Unifence fence slides left, right, forward, and backward. Because you
>>>>> can
>>>>> slide it backwards the end near the back of the saw table can be
>>>>> situated in
>>>>> front of the blade.
>>>>
>>>> Oh, that makes perfect sense.<sheesh>
>>>
>>>The fence is an extruded aluminum channel that attaches to the carrier
>>>with
>>>bolts secured by large wing nuts. By simply loosening the wing nuts you
>>>can
>>>adjust the fence towards you or away from you. This is very handy when
>>>you
>>>need to cross-cut something with the miter gauge; slide the fence towards
>>>you
>>>so that the far end is in front of the blade (prevents the cutoff from
>>>being
>>>trapped between the fence and the blade), use the fence scale to set the
>>>cutoff
>>>distance, register the end of the workpiece against the fence, then push
>>>through the blade with the miter gauge.
>>>
>>>More clearer?
>>
>> Much better. Thanks.
>>
>> Sounds like it's a bitch keep aligned.
>
>Not mine. I check it before any significant project and It very rarely needs
>any adjusting.
>Why would it?

Aluminum. Wingnuts. Sliding. All these things scream "alignment" to me.

Morgans wrote:
> "Lobby Dosser" <[email protected]> wrote
>>
>> It turns off when the grid power goes off. When the power returns,
>> the device does not start until the switch is pressed.
>
> As does the right portable GFIC device.

What is a "GFIC device"? Most GFCI devices do not reset with a power
failure.

--

-Mike-
[email protected]

On Aug 8, 8:09=A0am, "HeyBub" <[email protected]> wrote:
> Lobby Dosser wrote:
>
> > None of these saws have blade guards?
>
> Sure. All new saws come with blade guards and the guards receive about as
> much attention as the sixteen-page safety manuals that also accompany a n=
ew
> saw.
>
> Like the safety manuals, the blade guards are included with a new saw for
> the company's benefit, not the consumers'.

These are not mutually exclusive. The problem is that safety
equipment and ease of operation do seem to be mutually exclusive -
except for the SawStop. Then it's safety and affordability are
mutually exclusive. For now.

It's the same as seatbelts in a car. As a kid I used to bitch and
moan when my Mom would insist I put on the seatbelt. Then it became a
habit and I didn't even think about it. I'd be dead twice or thrice
over if it weren't for seatbelts

R

On Sat, 7 Aug 2010 23:34:55 -0400, "Ed Pawlowski" <[email protected]> wrote:

>
>"HeyBub" <[email protected]> wrote
>>
>> Some years ago, the federal government, in its infinite wisdom, and all
>> the while thinking of the children, mandated that washing machines come to
>> a complete stop in just a few seconds (like three).
>>
>> It shouldn't be hard to transfer that technology to table saws.
>>
>
>They have. Toss a dirty sock into the blade and it stops faster than a
>washing machine.

So *that's* what happens to the missing socks.

On Mon, 9 Aug 2010 08:22:11 -0700 (PDT), "[email protected]"
<[email protected]> wrote:

>On Aug 9, 9:36 am, Robatoy <[email protected]> wrote:
>> On Aug 9, 12:41 am, "Lobby Dosser" <[email protected]> wrote:

>> I just installed a new high-tech toilet. (For real) It has a dampening
>> mechanism for lowering the seat. I will be designing a logo in a
>> similar vein as Sawstop and call it LopStop. The days of having a seat
>> slam on one's schlong are over.
>
>How cold is the water?

The deeper water is coldest. DAMHIKT

"HeyBub" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote:
>> On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett"
>> <[email protected]> wrote:
>>
>>> I have been taking a basic wood working at a local community college.
>>>
>>> As you would expect, there is a heavy emphasis on safety.
>>>
>>> They have a collection of table saws including General, Delta Unisaw
>>> and PM66.
>>>
>>> Over the years there have been a few T/S accidents.
>>>
>>> Analyzing these accidents revealed the following:
>>>
>>> 1) The majority of accidents involved the PM66.
>>>
>>> 2) After shutting off, the PM66 required 20-30 seconds more to come
>>> to a rest than either the General or Unisaw.
>>>
>>> Looking at the saw blade, it was very difficult to see if the blade
>>> was still spinning.
>>
>> The only time I've ever come close to getting bitten by my Unisaw was
>> exactly this. A blade brake would be a great addition to any table
>> saw.
>>
>
> Some years ago, the federal government, in its infinite wisdom, and all
> the while thinking of the children, mandated that washing machines come to
> a complete stop in just a few seconds (like three).
>
> It shouldn't be hard to transfer that technology to table saws.
>

My Hitachi has a brake. Last shop I worked in (that I used a tablesaw),
there was a rule that when you turned it off, you cranked the blade down
below table height. Not always possible but could do so most of the time.

<[email protected]> wrote in message
news:[email protected]...
> On Mon, 9 Aug 2010 15:55:33 -0500, "Leon" <[email protected]> wrote:

>>
>>
>>BUT! Are'nt we talking about stopping a blade on a TS? Most contractors
>>and larger don't use universal motors and stopping the motor is not going
>>to
>>stop the blade. With belts, the blade will continue to spin enough to
>>hurt
>>you.
>
> Stopping the motor had better stop the blade, and darn quick. Certainly
> fast
> enough for the stated problem (not SawStop).


That would be the desired effect but with a contractors saw I would be
shocked if the motor stopped and the blade did not continue to spin a few
times.

>> None of these saws have blade guards?
>>
> We had two cabinet saws, neither had guards. I have owned two saws myself.
> First one, I had the guard on for about two days, then I took it off and
> never put it back. The one I have now, I never put the guard on. Didn't
> even know that I still had it. Ran across it the other day, still in the
> factory sealed bag.

You know, I used to be about like anyone else, in that I never used a guard
on a table saw. That all changed 18 years ago, when I took a job teaching
carpentry at the local high school. It was made very clear to me that any
and all safety devices available were to be used, at all times.

For the first year or so I fussed under my breath, any time I had to run the
table saw with the guard in place. Slowly, I began to realize that they
really were not all that bad, in nearly all cases.

Now, I seldom think a second thought about the guards. The obvious
exception is when using a tenion jig, or dado blade or other or other cuts
that do not go all the way through the workpiece. Even then, there are
guards available for the second class of cuts mentioned above.

So really, if everyone just made up their mind to keep with a guard until
they got used to it, you would find that it is a rare case where the guard
slows them down or prevents accurate cutting.
--
Jim in NC

"Lobby Dosser" <[email protected]> wrote in message
news:[email protected]...
> "Morgans" <[email protected]> wrote in message
> news:[email protected]...
>>
>> "Lobby Dosser" <[email protected]> wrote
>>
>>> Which tools should have, as they cannot start if they were shut down due
>>> to a power failure and the power is restored. No foul if the TV comes
>>> back on, but power tools are a whole other story.
>>
>> Have you ever seen the extension cord type device that is sold for tools
>> without magnetic starters to guard against exactly the thing you just
>> mentioned?
>
> Thanks, good to know and I'll google it as soon as I can think of what to
> search for.

I found this brand, but I think they are all GFCI's, too. I have found that
using a GFCI on top of a GFCI protected like can sometimes lead to excessive
false resets.

I will keep looking for a little while, but there is one type. Just find a
dealer and you are all set.
--
Jim in NC

Years ago I was attempting to create a CD rack (bored) using an old 3/4"
piece of oak. I was going to dado some exact width slots in it for the CD's
to stand up and tilt in, using a table mounted router.

After about the third or fourth dado slot I found the router bit came right
up through the top (backside) of the piece. The router depth locking screw
came loose (or I forgot to tighten it) and the vibration from the table made
the router gear rack screw itself right up through the 3/4" depth of the
wood instead on holding a 3/8" depth slot. I never figured that was possible
until I was staring at the 30K RPM bit by my fingers.

Wasted piece of wood (made it shorter) but the lesson was a good one
learned. Nobody got hurt but I never (If I ever did?) put my hands over top
of the router bit, anymore, no matter how thick the piece is. Pusher sticks
and distance became paramount.



"Morgans" <[email protected]> wrote in message
news:[email protected]...
You know, I used to be about like anyone else, in that I never used a guard
on a table saw. That all changed 18 years ago, when I took a job teaching
carpentry at the local high school. It was made very clear to me that any
and all safety devices available were to be used, at all times.

For the first year or so I fussed under my breath, any time I had to run the
table saw with the guard in place. Slowly, I began to realize that they
really were not all that bad, in nearly all cases.

Now, I seldom think a second thought about the guards. The obvious
exception is when using a tenion jig, or dado blade or other or other cuts
that do not go all the way through the workpiece. Even then, there are
guards available for the second class of cuts mentioned above.

So really, if everyone just made up their mind to keep with a guard until
they got used to it, you would find that it is a rare case where the guard
slows them down or prevents accurate cutting.
--
Jim in NC

<[email protected]> wrote

> Aluminum. Wingnuts. Sliding. All these things scream "alignment" to me.
>
Not really. The aluminum part that moves is up against the heavy casting
that is the part that securely locks to the saw. Once you have the casting
set, the aluminum repeats accurately (it is metal on metal with nothing to
let it become inaccurate) when it is tightened against the casting.

I usually keep mine accuratly adjusted to under a 32nd of an inch, and it
stays there for a long period of time. It takes something hitting it really
hard to knock it out of adjustment.

I don't understand people that get out a tape measure to check their setting
for every single cut. I set up my machine and scale to cut what I set it
on, and go to town. If I really need a super accurate cut, I check the
setting with a trial cut on a scrap. It is nearly always what I had the
scale set on.
--
Jim in NC

<[email protected]> wrote in message
news:[email protected]...
> On Sat, 7 Aug 2010 20:46:57 -0700, "Lew Hodgett" <[email protected]>
> wrote:
>
>>
>>"Nonnymus" wrote:
>>
>>> Strange, I had a PM66 and didn't feel it took that long to coast
>>> down. I'm not disagreeing- just commenting. It sure was a great
>>> saw and once adjusted with the TS Aligner, it stayed that way.
>>-------------------------------
>>If your saw is a stand alone device, you become aclimated to it;
>>however, if you have a shop with a PM66 AND say a Unisaw, it could be
>>a problem.
>>---------------------------------
>>>> Never used a Unifence, so can't say whether I'd like it better or
>>>> not.
>>>> Why?
>>--------------------------------------
>>1) No need for a separate stop block and clamp.
>
> Explain please.

Take a look at one to understand what I am about to explain. ;~) The
Unifence fence slides left, right, forward, and backward. Because you can
slide it backwards the end near the back of the saw table can be situated in
front of the blade.





>
>>2) Can quickly move fence to either side of the blade as req'd.
>
> Huh? The Beisemeyer moves pretty quickly.
>
>>3) If you mount a 1.5" thick sacrifical fence, you can use existing
>>calibrated tape measure directly without making a separate
>>calibration.
>
> Ok. I don't use the tape measure. I have one of the Wixey gauges, and
> still
> check it off a tooth.

"J. Clarke" <[email protected]> wrote

> Most of the cuts I've done in the past month have used a sled of some
> kind--for that the guard provided with my saw is not workable--while in
> some cases the sled will slide under it various pieces raise the guard so
> high that it might as well not be there.

No problem. Put a guard on the sled. With tools and bits and pieces
around, it takes about 30 seconds.

Have a tall fence on the sled, front and back, with a piece of plexi drilled
and screwed onto the sled fence, front and back. The plexi is only wide
enoug to cover past where you would never put your fingers, anyway, so it
does not impeed use, at al.

Have some blocks around of different height, for different thickness
workpieces.

Too wide for your sled to have a block on each side? Put both blocks on one
side, and let the plexi cantilever over the cutting area.

My point is, if you _ _have_ _ to have a guard on your saw, you _will_ be
creative and think of a way to get the job done, as you want to do it, and
still be safe.
--
Jim in NC

"HeyBub" <[email protected]> wrote in message
news:[email protected]...

>>
>
> Some years ago, the federal government, in its infinite wisdom, and all
> the while thinking of the children, mandated that washing machines come to
> a complete stop in just a few seconds (like three).
>
> It shouldn't be hard to transfer that technology to table saws.


Sawstop

I have seen iron filings bridge the contacts and energize a circuit in a
larger wall switch.


"Puckdropper" <puckdropper(at)yahoo(dot)com> wrote in message
news:[email protected]...
I've seen some things turn on by themselves, or more likely *not* turn
on. Usually what happened is the switch is either not in a full off
position or defective. The switch not being in a full off position is
difficult on most of the power tools I've used.

Now some of these modern computers... Those stupid things turn on when
power is connected.

Puckdropper
--
Never teach your apprentice everything you know.

I have dealt with many three phase and single phase dynamic braking
circuits, mostly in the 1-5 hp range and the number of phases on the motor
makes no difference, for braking ability.

The three phase braking circuits are more costly due to more contacts needed
to switch the load to the brake circuits. A simple SPDT switch will do for a
single phase saw.

The units I dealt with in 2000 ampere tapchangers typically used DC
injection (some were friction and some regenerative) and were set to time
out and allow the mechanism to coast onto a "top dead centre" position ready
for the next cycle. This could be made to stop "on the spot" if adjusted
this way but gave drift back to the brake initiating cam problems, at times
so the coast in was necessary. This would not be desirable to stop a machine
for a human usage.


<[email protected]> wrote in message
news:[email protected]...
Nah, there's nothing special about a three-phase motor that allows dynamic
braking.


>It is totally cost prohibitive for a single phase motor.

"Lobby Dosser" <[email protected]> wrote
>
> It turns off when the grid power goes off. When the power returns, the
> device does not start until the switch is pressed.

As does the right portable GFIC device.
--
Jim in NC

Lobby Dosser wrote:
>
> None of these saws have blade guards?

Sure. All new saws come with blade guards and the guards receive about as
much attention as the sixteen-page safety manuals that also accompany a new
saw.

Like the safety manuals, the blade guards are included with a new saw for
the company's benefit, not the consumers'.

Now that would depend on the area you are metered by.


LOL @ sync


<[email protected]> wrote in message
news:[email protected]...
The meter is free. Unless there is something intentionally installed in the
meter, all will run backwards if the energy goes the other way. The
hardware
needed to sync to the line, OTOH,...



On Mon, 9 Aug 2010 22:29:33 -0400, "Josepi" <[email protected]> wrote:
>The cost of the dual register meter would break even in how many decades?

"Mike Marlow" <[email protected]> wrote
>>
>> As does the right portable GFIC device.
>
> What is a "GFIC device"? Most GFCI devices do not reset with a power
> failure.

Yes I meant to type GFCI, but fumbled.

Most garden variety GFCI do not have to be reset manually after a power
failure. Some manufacturers have designed the circuit so that they have to
be manually reset when the power is withdrawn from the device. I don't know
which brands, but if you read up on it a little bit, you will see that is
the case.

That could be the reason why the garden variety automatic resetting ones
that most people have in their garages and kitchens and bathrooms cost about
12 bucks, but the ones meant for use in construction as a restart protection
device cost about 36 bucks.

Think about it. That is just a little microchip in those things. You can
program them to behave any way you want to. Since they do not make as many
for restart protection, they will cost more because of volume of production.
Plus the fact that if you need them for passing OSHA inspection, you need
them and will pay the premium price.

I do agree with you to a point. Most GFCI do not have to be reset when the
power is interrupted. If it has to be reset, it will usually plainly state
that fact in the documentation for the device. I found about 3
manufacturers that stated they have to be reset after power interruption
while I was searching for them a day or two ago.

Don't trust my word for it, though. Spend an hour or two searching for
them. They are out there.

Word.
--
Jim in NC

"Lobby Dosser" <[email protected]> wrote
>
> Pass and Seymour offer Manual Reset models, so probably the same price as
> Grainger. I think I'll just remember to unplug!

I found it for about 36 bucks, but lost it, now.
--
Jim in NC

<[email protected]> wrote in message
news:[email protected]...
> On Sat, 7 Aug 2010 19:31:08 -0700, "Lew Hodgett" <[email protected]>
> wrote:
>
>>I have been taking a basic wood working at a local community college.
>>
>>As you would expect, there is a heavy emphasis on safety.
>>
>>They have a collection of table saws including General, Delta Unisaw
>>and PM66.
>>
>>Over the years there have been a few T/S accidents.
>>
>>Analyzing these accidents revealed the following:
>>
>>1) The majority of accidents involved the PM66.
>>
>>2) After shutting off, the PM66 required 20-30 seconds more to come to
>>a rest than either the General or Unisaw.
>>
>>Looking at the saw blade, it was very difficult to see if the blade
>>was still spinning.
>
> The only time I've ever come close to getting bitten by my Unisaw was
> exactly
> this. A blade brake would be a great addition to any table saw.
>
>>You had to literally "feel" the blade still turning by touching the
>>table.
>>
>>Those of you who have a PM66 are aware of this phenomena; however, if
>>you buy a PM66, be aware.
>>
>>A PM66 is NOT the same as the General or the Unisaw.
>>
>>BTW: These saws were all equipped with Biesemeyer fences.
>>
>>Strong like bull, but give me a Unifence anyday.
>
> Never used a Unifence, so can't say whether I'd like it better or not.
> Why?

Strange, I had a PM66 and didn't feel it took that long to coast down. I'm
not disagreeing- just commenting. It sure was a great saw and once adjusted
with the TS Aligner, it stayed that way.

Nonny

"Lobby Dosser" <[email protected]> wrote in message
news:[email protected]...
> "Lew Hodgett" <[email protected]> wrote in message
> news:[email protected]...
>>
>> "CW" wrote:
>>> Last shop I worked in (that I used a tablesaw), there was a rule that
>>> when you turned it off, you cranked the blade down below table height.
>> ---------------------------------
>> Good rule.
>>
>> Lew
>>
>>
>
> None of these saws have blade guards?
>
We had two cabinet saws, neither had guards. I have owned two saws myself.
First one, I had the guard on for about two days, then I took it off and
never put it back. The one I have now, I never put the guard on. Didn't even
know that I still had it. Ran across it the other day, still in the factory
sealed bag.

"Lobby Dosser" <[email protected]> wrote in message
news:[email protected]...
> "J. Clarke" <[email protected]> wrote in message
>>
>> Well, Dosser, what part of "By requiring the user to press the reset
>> button after power loss the dangers of unexpected start-ups are averted"
>> are you having trouble with? Dossing in the lobby during remedial
>> reading were you, or was it just that you couldn't be assed to read the
>> whole 4 pages of big print before you spouted off?
>
>
> Maybe you could quote enough so that a person could see WTF you were
> talking about?


The simple solution to this problem is to simply plonk him. I did that a
few years ago and things are much nicer. He wants to argue, not actually
accomplish anything.

Do you have any references for that statement?

We were always informed that regenerative braking was just another type not
using an external stimulus.

No interlocking contactors are needed for regenerative braking. My first
chop saw used a SPDT switch in the handle. When you let go the motor got
shorted out. It's that circuitry simple. The switch doesn't last long, as no
ballast load is supplied to limit the arcing current when this happens. The
blades stopped very quickly, though.


"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
My previous post INCORRECTLY described "Regenerative braking" as
"Dynamic braking".

Dynamic braking still requires a set of interlocked contactors which
very much look like a reversing motor starter which is used to apply a
DC voltage to the motor windings.

You need a DC power supply and a time delay relay to accomplish
dynamic braking.

Take your choice, a motor mounted disc brake, a regenerative braking
or a dynamic braking approach.

All are expensive, have lots of control hardware and are used on 3
phase motors.

It is totally cost prohibitive for a single phase motor.

Lew




"Jeff Gorman" wrote:

> For an almost instant stop, I gather that something called DC
> injection is required and this requires a special and expensive
> motor.
----------------------------------

Robatoy wrote:
> On Aug 9, 11:22 am, "[email protected]" <[email protected]> wrote:
>> On Aug 9, 9:36 am, Robatoy <[email protected]> wrote:
>>
>>
>>
>>
>>
>>> On Aug 9, 12:41 am, "Lobby Dosser" <[email protected]> wrote:
>>>> "Larry W" <[email protected]> wrote in message
>>>> news:[email protected]...
>>>>> In article <[email protected]>,
>>>>> Mike Marlow <[email protected]> wrote:
>>>>> <...snipped...>
>>>>>> Nah - don't need sawstop for this need Leon. A simple brake is all that
>>>>>> is
>>>>>> necessary. With all of the chop saws that come with brakes today, it
>>>>>> really
>>>>>> should be no big deal for a table saw to have the same capability - it's
>>>>>> been around forever.
>>>>>> --
>>>>> I agree with that: I've seen brake setups on industrial machinery powered
>>>>> by 150 HP motors, geared down to about 30 RPM turning a roller that
>>>>> weighed
>>>>> a few tons, that could stop the roller in less than a 1/4 turn. I don't
>>>>> see
>>>>> why any sacrificial parts are necessary for a saw to do what the sawstop
>>>>> does. If Delta, Jet, etc. wanted to spend a little R&D money, they
>>>>> could build a safer saw that was _better_ than sawstop.
>>>> The claim to fame for SawStop is Not stopping the blade, but Sensing when
>>>> your pinkie finger touched the blade and Then stopping the blade before you
>>>> lose said pinkie.
>>> I just installed a new high-tech toilet. (For real) It has a dampening
>>> mechanism for lowering the seat. I will be designing a logo in a
>>> similar vein as Sawstop and call it LopStop. The days of having a seat
>>> slam on one's schlong are over.
>> How cold is the water?
>
> LOL
More importantly, how deep is it?

Not true.

I worked with many different dynamic and mechanical braking systems,
including DC Injection braking and none were any special motors. OTOH these
were industrial applications using larger HP units.

Geeeeez. My cheap $189 slide saw has dynamic braking on it and I doubt it is
any special motor. The blade had to worth half the price. It also has a
delay circuit that doesn't react immediately.


"Jeff Gorman" <[email protected]> wrote in message
news:[email protected]...
For an almost instant stop, I gather that something called DC injection is
required and this requires a special and expensive motor.

Jeff



"Father Haskell" <[email protected]> wrote
Electric brake -- short out the supply wires after cutting the power,
and the motor forces itself to stop.

"Lobby Dosser" <[email protected]> wrote

> Those are GFCI. What we're looking for is a cord with a switch that will
> go to Off on a power loss and require a Manual reset.

SOME of the GFCI variety will behave as we need them too, and need a manual
reset after the power is off. The trick is checking which ones are like
that.

I will try to remember and check the ones at Lowe's to see if they require a
manual reset when powered on.
--
Jim in NC

"Leon" <[email protected]> wrote

> Toothed belt,, as in like a timing belt? or a standard automotive belt?

Yes, my Dad's Craftsman table saw uses a toothed timing belt style for
driving the blade. They seem to break at the most inopertune times, so he
always had an extra one on hand so he could quickly change it and get back
to work.
--
Jim in NC