On Sat, 25 Dec 2004 23:09:55 -0500, Nova <[email protected]>
calmly ranted:
>Larry Jaques wrote:
>
><snipped>
>
>> I just don't buy that C-frame flex thing at all. Wider bands and the
>> higher tension needed to run them would be the only cause of frame
>> stress that I can see. No, I take that back. The frame may have more
>> stress AT the lower wheel bearing mount during heavy cuts. The wheel
>> being slightly deflected upward up would also result in lower tension
>> on the blade, with the tension spring attempting to take up that
>> slack.
>
>The upper and lower wheels move in sync because of the blade tension.. Because the
>wheels move in sync any stretching of the blade will cause the slack to be on the gap
>side. The stress on C-frame is also caused by the wheels moving in sync.
Oh, so it's the stretching that causes the stress? <giggle>
You lost me with your last sentence. What part of synchronization
(other than the tension which puts them there) causes stress?
-------------------------------------------------------------
* * Humorous T-shirts Online
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<[email protected]> wrote in message
news:[email protected]...
> Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
> it would be too much for my little BS. Has anyone had any experience
> with big motors on small bandsaws? Would this be the funny car of the
> woodshop?
>
> Regards,
> H
>
I have a cheap 12" Crapsman, aluminum framed bandsaw. It came with a 1/3 HP
motor. It was not enough! I had a 1-1/2 HP motor laying around that I
slapped into it! Works much better now!
I don't think you can have too much HP!
Greg
"Edwin Pawlowski" <[email protected]> wrote in message
news:[email protected]...
>
> "Greg O" <[email protected]> wrote in message
> > I don't think you can have too much HP!
> > Greg
>
> If all the lights on your block dim when you turn on the saw, you have too
> much horsepower.
>
>
If all the lights go out, maybe, but just dim? No problem!
Greg
"Duane Bozarth" <[email protected]> wrote in message
news:[email protected]...
> Larry Jaques wrote:
> ...
> > How could the inertial mass of the blade and aluminum wheel (under 10
> > pounds would be my highest guess) cause any more tension on the frame
> > than the tension adjustment spring, which is in the hundreds of
> > pounds? I still don't buy it, but I would like to hear the Griz
> > tech's explanation.
>
> It's not the inertial mass we're talking about here...it's the extra
> torque exerted by the larger motor when more force is exerted
> (particularly suddenly) by the blade through the material...
I don't agree, all that extra tourque is dilivered to the wood being cut,
the upper wheel don't see a thing. All the frame and upper wheel sees is
blade tension.
I don't see the problem with a bgger motor, 'cept that Grizzly has to put a
limit somewhere!
Greg
Bob wrote:
> An electric motor HP rating is what its capable of putting out. If you do
> not stress it, it does not produce any more HP than your existing motor. The
> only way to make it produce the full 2HP is to really load it up.
I wish my electric meter believed that.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Nova wrote:
>
> Bob wrote:
>
> > An electric motor HP rating is what its capable of putting out. If you do
> > not stress it, it does not produce any more HP than your existing motor. The
> > only way to make it produce the full 2HP is to really load it up.
>
> I wish my electric meter believed that.
>
:)
What a testament to the failure of science education in the general
populace (Bob, not you Nova)... :(
CW wrote:
> No problem. 2horspower is still pretty weenie.
It depends. Most 14" bandsaw have a problem providing enough tension for a
3/4" blade without the frame flexing. Given a situation where a 2 HP motor
would be beneficial, unless the saw was designed to handle that size motor,
the frame of the saw would most likely flex, dropping the tension on the
blade and result in a barreled cut. Hopefully that's the worse that would
happen.
Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
"no" on a 2 HP.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Larry Jaques wrote:
> On Thu, 23 Dec 2004 19:27:06 -0500, Nova <[email protected]>
> calmly ranted:
>
> >CW wrote:
> >
> >> No problem. 2horspower is still pretty weenie.
> >
> >It depends. Most 14" bandsaw have a problem providing enough tension for a
> >3/4" blade without the frame flexing. Given a situation where a 2 HP motor
> >would be beneficial, unless the saw was designed to handle that size motor,
> >the frame of the saw would most likely flex, dropping the tension on the
> >blade and result in a barreled cut. Hopefully that's the worse that would
> >happen.
>
> The motor horsepower shouldn't be of any concern (unless too small.)
> I'd think the size of blade and the resultant tension required would
> be the limiting factors.
Blade friction. When you start resawing lumber where the power is needed a
larger motor, say 2 HP will torque the frame. It will still pull the blade
through the wood but with the flex the blade will "bunch up" above the drag. A
smaller motor will stall before this happens. With my G1019 with the riser i got
the distinct impression from Grizzly's tech support it would be risking snapping
the frame with a 2 HP motor.
> >Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
> >"no" on a 2 HP.
> Did they say why? Were they saying no to the combo or to the larger motor? My
> guess is the former, not the latter.
If you mean the combo of the G1019 and a 2 HP motor, yes the saw was designed
for a 3/4 HP motor. I don't know if the riser kit figured in, but I imagine it
would. The tech says a 1 HP wouldn't be a problem, 1.5 was questionable and 2
HP was out.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Mark Jerde wrote:
> Well...... ;-) I made it 2/3 rds of the way to a mechanical engineering
> degree before switching to computer science. As an "inganeering" student I
> lernt alot about "conservation of energy" and the like. ;-)
>
> If you hook up a 1 HP motor and it turns the band saw at "X" FPM, and then
> you hook up a 2 HP (or 10 HP or 100 HP or 10M HP) motor and it also turns
> the saw at "X" FPM, what is the larger motor doing to consume more
> electrons? Radiating heat? Shooting arcs in the air? Writing its
> congressperson? It takes the same amount of power to spin the same machine
> at the same speed, so if there is a difference in electrons sacrificed by
> the different sized motors it has to be due to efficiency differences in the
> motors and/or the motors sending the electrons off to do other things.
<snip>
Start up current. Have you ever seen a 2 HP motor wired for 110 volts dim the
lights while it spins up? I agree that once the motor spins up the running
current difference is only that needed to keep the more massive armature turning
and overcoming more friction of the larger bearings of the bigger motor, but I
imagine you could run a 1/2 HP motor for 15 minutes on the current drawn by 2 HP
motor on start up alone.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Larry Jaques wrote:
> Blade friction?!? The motor drives the lower wheel which drives the
> blade and the upper wheel goes along for the ride. Whether you have
> a 0.5 or a 5.0 hp motor should make little difference, since the
> weight of the blade and upper wheel will be the same mass no matter
> what motor.
The blade friction is still there and has to be overcome. Unless the blade slips on
the wheels the torque is taken by the frame. Think of it as pushing a rope which is
the reason for barreled cuts.
> >> >Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
> >> >"no" on a 2 HP.
> >
> >> Did they say why? Were they saying no to the combo or to the larger motor? My
> >> guess is the former, not the latter.
> >
> >If you mean the combo of the G1019 and a 2 HP motor, yes the saw was designed
> >for a 3/4 HP motor. I don't know if the riser kit figured in, but I imagine it
> >would. The tech says a 1 HP wouldn't be a problem, 1.5 was questionable and 2
> >HP was out.
>
> No, I meant the wider blade and higher tension. But did you tell him
> you'd be using low-tension Suffolk Timberwolfs? (Or were you?) How
> much difference in mass could the longer/wider blade make? 8 ounces?
> That slim margin would easily be quintupled by extra tension on the
> original bandsaw with the original spring. Inertial mass _can't_ be
> it.
I normally use a 1/2" Timberwolf blade which Suffolk recommended for the saw. I
tried there 3/4" and as Suffolk predicted the saw can't handle the tensions produced
by the added blade friction of the extra 1/4" blade width while resawing. It is
especially noticeable when attempting to saw "green" lumber (i.e. milling short logs
into boards) which has more of a tendency to bind the blade.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
George wrote:
...
> How about this:
>
> The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
> causing the blade to bunch into the gap. Doesn't take much difference in
> speed to start the process, which then increases in effect as the bunched
> part slows....
The upper wheel isn't free-wheeling, it's driven/pulled by the
blade...the blade makes the wheel move, not the other way round...
Larry Jaques wrote:
>
...
> The only part I can see being stressed by having a larger motor would
> be the lower wheel (major) and its bearing (minor). Startup might be
> quicker, creating higher initial (and inertial) stress, and it would
> be able to do more work when making heavy cuts while resawing. The
> upper wheel and frame are merely used as guides for the band.
>
> I just don't buy that C-frame flex thing at all. Wider bands and the
> higher tension needed to run them would be the only cause of frame
> stress that I can see. No, I take that back. The frame may have more
> stress AT the lower wheel bearing mount during heavy cuts. The wheel
> being slightly deflected upward up would also result in lower tension
> on the blade, with the tension spring attempting to take up that
> slack.
>
You've got it except you're overlooking the fact that the blade is
pulling on the outside of the upper wheel which is applying torque to
the frame...as the motor applies more power to the blade this gets
transferred to a higher load which could in extreme case, cause the
support to fail...
Roy Smith wrote:
>
> In article <[email protected]>,
> Duane Bozarth <[email protected]> wrote:
> >George wrote:
> >...
> >> How about this:
> >>
> >> The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
> >> causing the blade to bunch into the gap. Doesn't take much difference in
> >> speed to start the process, which then increases in effect as the bunched
> >> part slows....
> >
> >The upper wheel isn't free-wheeling, it's driven/pulled by the
> >blade...the blade makes the wheel move, not the other way round...
>
> On the other hand, the upper wheel has rotational inertia. It's an
> interesting dynamics problem to figure out exactly what happens if you
> get the whole system up to speed and then place drag on the
> downward-moving blade.
Not a tremendous amount, however, as the mass of the wheel isn't all
<that> great...
But, you're correct, it's a fairly complex dynamical system if one
accounts for all effects including blade slip, stretch, ...
Larry Jaques wrote:
...
> How could the inertial mass of the blade and aluminum wheel (under 10
> pounds would be my highest guess) cause any more tension on the frame
> than the tension adjustment spring, which is in the hundreds of
> pounds? I still don't buy it, but I would like to hear the Griz
> tech's explanation.
It's not the inertial mass we're talking about here...it's the extra
torque exerted by the larger motor when more force is exerted
(particularly suddenly) by the blade through the material...
Sorry, I didn't think of this until I had posted previous...
Think of it this way as an approximation...the extra force when the
blade hits an additional obstruction is essentially same as suddenly
grabbing a hold of the blade and yanking downward---if the motor is
over-sized, it won't stall but will just keep on pulling until something
gives...given the moment arm of the upper axle around the support
column, that could well be the place.
Larry Jaques wrote:
<snipped>
> I just don't buy that C-frame flex thing at all. Wider bands and the
> higher tension needed to run them would be the only cause of frame
> stress that I can see. No, I take that back. The frame may have more
> stress AT the lower wheel bearing mount during heavy cuts. The wheel
> being slightly deflected upward up would also result in lower tension
> on the blade, with the tension spring attempting to take up that
> slack.
The upper and lower wheels move in sync because of the blade tension.. Because the
wheels move in sync any stretching of the blade will cause the slack to be on the gap
side. The stress on C-frame is also caused by the wheels moving in sync.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Larry Jaques wrote:
> Oh, so it's the stretching that causes the stress? <giggle>
> You lost me with your last sentence. What part of synchronization
> (other than the tension which puts them there) causes stress?
The blade stretch takes place from the point of the bind to the drive wheel. Because the
wheels attempt to move in sync the added length (along with the slop caused ny the slight
compression of the tires and frame flex) is transferred around both wheels to the the top
of the piece being cut. Although the blade isn't fixed to the frame other than being
restricted by the piece being cut, think of the wheels as acting as the cams in a compound
bow.
--
Jack Novak
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
"Bob" <[email protected]> wrote in message
news:[email protected]...
>
> <[email protected]> wrote in message
> news:[email protected]...
> > Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
> > it would be too much for my little BS. Has anyone had any experience
> > with big motors on small bandsaws? Would this be the funny car of the
> > woodshop?
>
> An electric motor HP rating is what its capable of putting out. If you do
> not stress it, it does not produce any more HP than your existing motor.
The
> only way to make it produce the full 2HP is to really load it up. So you
> are in control. Go for it.
Two horse 110 is stretching things, which make me wonder if it's not one of
those 3450 cap start cap run types. If so, remember to change the pulleys.
The belt effectively limits the power available to the tool, but with a
bandsaw's low torque requirements, shouldn't be a problem, just overkill.
"Larry Jaques" <novalidaddress@di\/ersify.com> wrote in message
news:[email protected]...
> On Fri, 24 Dec 2004 08:49:06 -0500, Nova <[email protected]>
> calmly ranted:
>
> >The blade friction is still there and has to be overcome. Unless the
blade slips on
> >the wheels the torque is taken by the frame. Think of it as pushing a
rope which is
> >the reason for barreled cuts.
>
> I think of it as the wheel pulling the teeth down, into the wood. The
> majority of the tension on the blade is between the table and the
> bottom wheel on the downward side. Since the wheels are connected,
> there may be a very minor amount of "pushing", but the fact that the
> band is laying on the -outside- of the wheels precludes much of that.
> Any attempt at pushing would simply make space between the blade and
> the wheel, and that could come only if there was no tension on the
> blade at all. No, it is my understanding that barrel cuts are the
> result of insufficient tension on the blade.
>
How about this:
The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
causing the blade to bunch into the gap. Doesn't take much difference in
speed to start the process, which then increases in effect as the bunched
part slows....
It continues to rotate at its original speed for a few msec after the load
slows the lower. Within the limit of blade/frame flex, it crams.
It's rotational inertia that counts.
<[email protected]> wrote in message
news:[email protected]...
> the upper wheel is an idler and has less mass than the driven lower.
> just how is it going to get ahead?
<[email protected]> wrote in message
news:[email protected]...
> On Fri, 24 Dec 2004 17:34:46 -0500, "George" <george@least> wrote:
>
> >It continues to rotate at its original speed for a few msec after the
load
> >slows the lower. Within the limit of blade/frame flex, it crams.
> >
> >It's rotational inertia that counts.
>
> 1) this is a tiny force in the context of a bandsaw.
>
> 2) putting a bigger motor on it doesn't change the upper wheel
> configuration a bit.
>
My explanation was how the blade begins to flex. You may charge any
windmills you care to without changing the basic dynamic equation which
anyone who owns the standard 14" bandsaw knows by the sound of the blade
slapping on the left - push a rope syndrome - or the right, where the blade
slows and flexes at the top of the cut - even under tiny force. It's
differential which counts, and in a dynamic system with four sources of
built-in-flex - the blade, the frame, the spring and the tires, in
conjunction with differential friction on a driven and free-wheel, there's a
bit more of that than necessary at times.
As to HP limits, my initial in this thread summed up my opinion - wouldn't
hurt, but there are better uses for 2 HP, if it is 2HP @ 115, motors than
for bandsaws, which are belt and blade limited in their use of torque. Now
that I know it's a Grizz we're talking about, my experience with breakage in
a number of their castings makes me side with the phone tech.
Roy Smith wrote:
> The only time you really need the power and tension is when you're
> resawing, and when you're resawing, there's usually very little
> material on one side of the blade. So, it seems to me you could
> solve the frame flexing problem by having a removable strut which
> could be fitted as a compression member between the upper frame and
> the table when resawing.
>
> I've never seen such a thing on a bandsaw, but I find it hard to
> believe nobody else has thought of it before me. Does such a thing
> exist?
File the patent. This looks like one of those "Why didn't I think of
that???" things. ;-)
-- Mark
On Fri, 24 Dec 2004 03:52:21 GMT, "Mark Jerde"
<[email protected]> wrote:
>P.S. Those who finished engineering degrees are invited to correct my
>mis/mal understandings. ;-)
I think that the difference involved occurs when both are under load.
A bull and a mouse can pull a small toy behind them a the same speed
if the bull takes it slow and easy. If the toy sticks against
something, the mouse will stall. The bull will destroy the toy, the
something, and anything else that gets in the way. It's smart to not
overdo it.
On Wed, 22 Dec 2004 04:13:56 GMT, "BillyBob"
<[email protected]> vaguely proposed a theory
......and in reply I say!:
remove ns from my header address to reply via email
>
>"Duane Bozarth" <[email protected]> wrote in message
>news:[email protected]...
>
>> What a testament to the failure of science education in the general
>> populace (Bob, not you Nova)... :(
>
>Are you saying my statement was wrong?
I feel that the quote below is because of two factors (rusty memories
struggle up through the ooze):
- The motor is not running at synchronous spped eve with no load, so a
larger HP motor wil draw fractioannly more.
- The motor will run at near-synchronous until it stall, then it will
start to draw the (much) heavier "starting" current, although it's
failing to do the job. Because it;s running at near-synchronous while
it's working properly, the correctly-matched motor will use less power
even when fully loaded. Less wastage.
However, if I had the choice as a hobbyist between a free 2HP motor
and a $100 1 hp one, I woud use the free one for sure! <G>
http://www.eng-tips.com/gviewthread.cfm/lev2/11/lev3/47/pid/237/qid/18465
"4.2.2. Efficiency at Low Load
When a motor has a greater rating than the unit it is driving
requires, the motor operates at only partial load. In this state, the
efficiency of the motor is reduced (see Figure 4.2 ). The use of
oversized motors is fairly common because of the following
conditions:"
"Replacement of underloaded motors with smaller motors will allow a
fully loaded smaller motor to operate at a higher efficiency. This
arrangement is generally most economical for larger motors, and
only when they are operating at less than one-third to one-half
capacity, depending on their size"
"Duane Bozarth" <[email protected]> wrote in message
news:[email protected]...
> What a testament to the failure of science education in the general
> populace (Bob, not you Nova)... :(
Are you saying my statement was wrong?
Bob
"Old Nick" <[email protected]> wrote in message
news:[email protected]...
> - The motor is not running at synchronous spped eve with no load, so a
> larger HP motor wil draw fractioannly more.
The difference is not that great at no load speed.
> - The motor will run at near-synchronous until it stall, then it will
> start to draw the (much) heavier "starting" current,
Typical loaded speed is 95% of synchronous speed. I don't know if that's
what you meant by "near-synchronous". However when it gets near stall
(break-down torque), the speed will be significantly slower. Breakdown
torque might typically occurs at 70% of synchronous speed - quite a bit
slower.
> "4.2.2. Efficiency at Low Load
Your discussion of efficiency is accurate, but I don't think its relavent to
the context of the OP's question - concern for damage ("too much for my
little band saw"). Basically I was just saying that motor characteristics
are such that it won't hurt the saw, if you don't force the saw to do things
its not designed to withstand.
Bob
"Nova" <[email protected]> wrote in message
news:[email protected]...
> I wish my electric meter believed that.
It does. You just don't believe its telling you the truth.
Bob
No problem. 2horspower is still pretty weenie.
<[email protected]> wrote in message
news:[email protected]...
> Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
> it would be too much for my little BS. Has anyone had any experience
> with big motors on small bandsaws? Would this be the funny car of the
> woodshop?
>
> Regards,
> H
>
On Sat, 25 Dec 2004 08:13:06 -0600, Duane Bozarth
<[email protected]> wrote:
>Greg O wrote:
>>
>...
>> I don't agree, all that extra tourque is dilivered to the wood being cut,
>> the upper wheel don't see a thing. All the frame and upper wheel sees is
>> blade tension.
>...
>
>How does the torque get delivered to the wood being cut???
The blade is being *pulled* down through by the lower wheel, held fast
by friction to the rubber around the wheel. The upper wheel is
freewheeling. An old sawmill at Upper Canada Village in Ontario
Canada uses a straight blade that cuts on the way down, being pulled
by the rotating jointed mechanism at the base. That way the wood is
also held fast to the table during the cut. Japanese hand saws cut on
the pull stroke. It makes sense.
[It's not strictly "torque", which is a turning force, at the wood
surface, where the blade is being pulled down with sharp edges into
the wood, ripping [tiny] chunks out of it.]
Merry Christmas.
On Sat, 25 Dec 2004 08:13:06 -0600, Duane Bozarth
<[email protected]> wrote:
>Greg O wrote:
>>
>...
>> I don't agree, all that extra tourque is dilivered to the wood being cut,
>> the upper wheel don't see a thing. All the frame and upper wheel sees is
>> blade tension.
>...
>
>How does the torque get delivered to the wood being cut???
by the blade being pulled down through the wood by the lower wheel
being turned by the motor.
the upper wheel is for tension and tracking only.
On Sat, 25 Dec 2004 08:00:46 -0500, "George" <george@least> wrote:
>
><[email protected]> wrote in message
>news:[email protected]...
>> On Fri, 24 Dec 2004 17:34:46 -0500, "George" <george@least> wrote:
>>
>> >It continues to rotate at its original speed for a few msec after the
>load
>> >slows the lower. Within the limit of blade/frame flex, it crams.
>> >
>> >It's rotational inertia that counts.
>>
>> 1) this is a tiny force in the context of a bandsaw.
>>
>> 2) putting a bigger motor on it doesn't change the upper wheel
>> configuration a bit.
>>
>
>My explanation was how the blade begins to flex. You may charge any
>windmills you care to without changing the basic dynamic equation which
>anyone who owns the standard 14" bandsaw knows by the sound of the blade
>slapping on the left - push a rope syndrome - or the right, where the blade
>slows and flexes at the top of the cut - even under tiny force. It's
>differential which counts, and in a dynamic system with four sources of
>built-in-flex - the blade, the frame, the spring and the tires, in
>conjunction with differential friction on a driven and free-wheel, there's a
>bit more of that than necessary at times.
heck, if anything a bigger motor should reduce that by slowing down
less under load.
>
>As to HP limits, my initial in this thread summed up my opinion - wouldn't
>hurt, but there are better uses for 2 HP, if it is 2HP @ 115, motors than
>for bandsaws, which are belt and blade limited in their use of torque. Now
>that I know it's a Grizz we're talking about, my experience with breakage in
>a number of their castings makes me side with the phone tech.
>
I agree that it wouldn't hurt, and that you'd be unlikely to pull the
full 2HP with that saw.
my us made bandsaw has a factory 2hp motor on it- although it's an 18"
and has a tube steel frame.
the only griz bandsaw I ever used was also an 18", and IIRC it also
had a 2HP motor on it. I assume that the griz 14" is a fairly generic
asian delta clone.
Duane Bozarth wrote:
> Nova wrote:
>>
>> Bob wrote:
>>
>>> An electric motor HP rating is what its capable of putting out. If
>>> you do not stress it, it does not produce any more HP than your
>>> existing motor. The only way to make it produce the full 2HP is to
>>> really load it up.
>>
>> I wish my electric meter believed that.
>>
>
> :)
>
> What a testament to the failure of science education in the general
> populace (Bob, not you Nova)... :(
Well...... ;-) I made it 2/3 rds of the way to a mechanical engineering
degree before switching to computer science. As an "inganeering" student I
lernt alot about "conservation of energy" and the like. ;-)
If you hook up a 1 HP motor and it turns the band saw at "X" FPM, and then
you hook up a 2 HP (or 10 HP or 100 HP or 10M HP) motor and it also turns
the saw at "X" FPM, what is the larger motor doing to consume more
electrons? Radiating heat? Shooting arcs in the air? Writing its
congressperson? It takes the same amount of power to spin the same machine
at the same speed, so if there is a difference in electrons sacrificed by
the different sized motors it has to be due to efficiency differences in the
motors and/or the motors sending the electrons off to do other things.
When my 14" Jet BS is running but not actually cutting wood, I haven't
noticed the motor housing glowing red, or sparks jumping out of the motor,
or letters to congresscritters coming out of the motor. Therefore I have to
conclude that the motor is consuming only enough electrons to keep the the
band saw mechanisms turning at a constanst speed against the forces of
friction in the bearings, the unwillingness of the band saw blade to be bent
and unbent, and the link belt groaning and complaining as it is bent and
straightened. If you ignore internal differences in motors and hook up a
100 HP motor to the same Jet 14" band saw and it also drives the BS at the
same speed, it is impossible for the difference of a single electron to flow
through my electric meter -- unless the larger motor is shunting additional
electrons elsewhere.
When idling at a stoplight, I'll bet a Chevette and a Corvette are
*producing* basically the same HP, even though there is a substantial
difference in their maximum HP. ;-)
-- Mark
P.S. Those who finished engineering degrees are invited to correct my
mis/mal understandings. ;-)
On 24 Dec 2004 13:10:10 -0500, [email protected] (Roy Smith) wrote:
>In article <[email protected]>,
>Duane Bozarth <[email protected]> wrote:
>>George wrote:
>>...
>>> How about this:
>>>
>>> The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
>>> causing the blade to bunch into the gap. Doesn't take much difference in
>>> speed to start the process, which then increases in effect as the bunched
>>> part slows....
>>
>>The upper wheel isn't free-wheeling, it's driven/pulled by the
>>blade...the blade makes the wheel move, not the other way round...
>
>On the other hand, the upper wheel has rotational inertia. It's an
>interesting dynamics problem to figure out exactly what happens if you
>get the whole system up to speed and then place drag on the
>downward-moving blade.
that is exactly what happens every time you cut with the saw. it's
what they are designed to do, exactly.
On Fri, 24 Dec 2004 17:34:46 -0500, "George" <george@least> wrote:
>It continues to rotate at its original speed for a few msec after the load
>slows the lower. Within the limit of blade/frame flex, it crams.
>
>It's rotational inertia that counts.
1) this is a tiny force in the context of a bandsaw.
2) putting a bigger motor on it doesn't change the upper wheel
configuration a bit.
>
><[email protected]> wrote in message
>news:[email protected]...
>
>> the upper wheel is an idler and has less mass than the driven lower.
>> just how is it going to get ahead?
>
bridger responds:
>On Fri, 24 Dec 2004 17:34:46 -0500, "George" <george@least> wrote:
>
>>It continues to rotate at its original speed for a few msec after the load
>>slows the lower. Within the limit of blade/frame flex, it crams.
>>
>>It's rotational inertia that counts.
>
>1) this is a tiny force in the context of a bandsaw.
>
>2) putting a bigger motor on it doesn't change the upper wheel
>configuration a bit.
>
>
>
>
>>
>><[email protected]> wrote in message
>>news:[email protected]...
>>
>>> the upper wheel is an idler and has less mass than the driven lower.
>>> just how is it going to get ahead?
You are right, as I see it. I think a smarter question would involve something
like what is the maximum useful HP for a replacement motor on a 14" bandsaw.
That would probably run up on 2 horses. There's simply not a lot of point in
running that blade off a 5 HP motor unless you do constant resawing of ipe or
something similar...and I doubt even then.
Charlie Self
"Political language... is designed to make lies sound truthful and murder
respectable, and to give an appearance of solidity to pure wind." George Orwell
On 25 Dec 2004 10:13:49 GMT, [email protected] (Charlie Self)
wrote:
>bridger responds:
>
>>On Fri, 24 Dec 2004 17:34:46 -0500, "George" <george@least> wrote:
>>
>>>It continues to rotate at its original speed for a few msec after the load
>>>slows the lower. Within the limit of blade/frame flex, it crams.
>>>
>>>It's rotational inertia that counts.
>>
>>1) this is a tiny force in the context of a bandsaw.
>>
>>2) putting a bigger motor on it doesn't change the upper wheel
>>configuration a bit.
>>
>>
>>
>>
>>>
>>><[email protected]> wrote in message
>>>news:[email protected]...
>>>
>>>> the upper wheel is an idler and has less mass than the driven lower.
>>>> just how is it going to get ahead?
>
>You are right, as I see it. I think a smarter question would involve something
>like what is the maximum useful HP for a replacement motor on a 14" bandsaw.
>That would probably run up on 2 horses. There's simply not a lot of point in
>running that blade off a 5 HP motor unless you do constant resawing of ipe or
>something similar...and I doubt even then.
>
>Charlie Self
I'd think 2 horse would be fine. probably more than you'll actually
draw with that saw, but a little extra horsie never hurt anybody.
I think that way before you snapped the arm the saw would give you all
kinds of warnings- it'd be throwing bands and slipping belts and
tearing up tires all over the place.
In article <[email protected]>, Charlie Self wrote:
> You are right, as I see it. I think a smarter question would involve something
> like what is the maximum useful HP for a replacement motor on a 14" bandsaw.
> That would probably run up on 2 horses. There's simply not a lot of point in
> running that blade off a 5 HP motor unless you do constant resawing of ipe or
> something similar...and I doubt even then.
Actually, I was thinking that a two or three horsepower three phase motor
might be useful if you power it with an inverter. As I understand it, the
torque would stay the same while you'd be able to vary the speed of the
blade.
On Fri, 24 Dec 2004 08:49:06 -0500, Nova <[email protected]>
calmly ranted:
>The blade friction is still there and has to be overcome. Unless the blade slips on
>the wheels the torque is taken by the frame. Think of it as pushing a rope which is
>the reason for barreled cuts.
I think of it as the wheel pulling the teeth down, into the wood. The
majority of the tension on the blade is between the table and the
bottom wheel on the downward side. Since the wheels are connected,
there may be a very minor amount of "pushing", but the fact that the
band is laying on the -outside- of the wheels precludes much of that.
Any attempt at pushing would simply make space between the blade and
the wheel, and that could come only if there was no tension on the
blade at all. No, it is my understanding that barrel cuts are the
result of insufficient tension on the blade.
>> No, I meant the wider blade and higher tension. But did you tell him
>> you'd be using low-tension Suffolk Timberwolfs? (Or were you?) How
>> much difference in mass could the longer/wider blade make? 8 ounces?
>> That slim margin would easily be quintupled by extra tension on the
>> original bandsaw with the original spring. Inertial mass _can't_ be
>> it.
The only part I can see being stressed by having a larger motor would
be the lower wheel (major) and its bearing (minor). Startup might be
quicker, creating higher initial (and inertial) stress, and it would
be able to do more work when making heavy cuts while resawing. The
upper wheel and frame are merely used as guides for the band.
I just don't buy that C-frame flex thing at all. Wider bands and the
higher tension needed to run them would be the only cause of frame
stress that I can see. No, I take that back. The frame may have more
stress AT the lower wheel bearing mount during heavy cuts. The wheel
being slightly deflected upward up would also result in lower tension
on the blade, with the tension spring attempting to take up that
slack.
Maybe the guy at Griz could expand on his concerns. I'd be very
interested (despite having their old heavy-duty 18" G1012.)
>I normally use a 1/2" Timberwolf blade which Suffolk recommended for the saw. I
>tried there 3/4" and as Suffolk predicted the saw can't handle the tensions produced
>by the added blade friction of the extra 1/4" blade width while resawing. It is
>especially noticeable when attempting to saw "green" lumber (i.e. milling short logs
>into boards) which has more of a tendency to bind the blade.
Yeah, and they make resaw blades for both green and dried wood,
with different set, hook angles, gullet depth, etc. for each one.
--
"Most Folks Are As Happy As They Make Up Their Minds To Be"
-Abraham Lincoln
-----------------------------------------------------------
www.diversify.com - Happy Website Development
[email protected] wrote:
> Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
> it would be too much for my little BS. Has anyone had any experience
> with big motors on small bandsaws? Would this be the funny car of the
> woodshop?
Until it's big enough to break expensive things if something gets hung up
bigger is better with motors. Now if you were talking 200 horsepower,
which is enough to sling the whole saw through the roof if something goes
awry, then I'd say maybe it was too much motor, but 2 should be fine on a
14". If it was one of the little bitty miniature hobbyist jobs I'd be
worried about twisting off the drive axle or slipping the pulley, but a 14"
unless it's a real piece of garbage should have no trouble with 2 HP.
> Regards,
> H
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
Nova wrote:
> Bob wrote:
>
>> An electric motor HP rating is what its capable of putting out. If you do
>> not stress it, it does not produce any more HP than your existing motor.
>> The only way to make it produce the full 2HP is to really load it up.
>
> I wish my electric meter believed that.
Have you checked it with an ammeter?
>
> --
> Jack Novak
> Buffalo, NY - USA
> (Remove "SPAM" from email address to reply)
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
Mark Jerde wrote:
> Duane Bozarth wrote:
>> Nova wrote:
>>>
>>> Bob wrote:
>>>
>>>> An electric motor HP rating is what its capable of putting out. If
>>>> you do not stress it, it does not produce any more HP than your
>>>> existing motor. The only way to make it produce the full 2HP is to
>>>> really load it up.
>>>
>>> I wish my electric meter believed that.
>>>
>>
>> :)
>>
>> What a testament to the failure of science education in the general
>> populace (Bob, not you Nova)... :(
>
> Well...... ;-) I made it 2/3 rds of the way to a mechanical
> engineering
> degree before switching to computer science. As an "inganeering" student
> I
> lernt alot about "conservation of energy" and the like. ;-)
>
> If you hook up a 1 HP motor and it turns the band saw at "X" FPM, and then
> you hook up a 2 HP (or 10 HP or 100 HP or 10M HP) motor and it also turns
> the saw at "X" FPM, what is the larger motor doing to consume more
> electrons? Radiating heat? Shooting arcs in the air? Writing its
> congressperson? It takes the same amount of power to spin the same
> machine at the same speed, so if there is a difference in electrons
> sacrificed by the different sized motors it has to be due to efficiency
> differences in the motors and/or the motors sending the electrons off to
> do other things.
>
> When my 14" Jet BS is running but not actually cutting wood, I haven't
> noticed the motor housing glowing red, or sparks jumping out of the motor,
> or letters to congresscritters coming out of the motor. Therefore I have
> to conclude that the motor is consuming only enough electrons to keep the
> the band saw mechanisms turning at a constanst speed against the forces of
> friction in the bearings, the unwillingness of the band saw blade to be
> bent and unbent, and the link belt groaning and complaining as it is bent
> and
> straightened. If you ignore internal differences in motors and hook up a
> 100 HP motor to the same Jet 14" band saw and it also drives the BS at the
> same speed, it is impossible for the difference of a single electron to
> flow through my electric meter -- unless the larger motor is shunting
> additional electrons elsewhere.
>
> When idling at a stoplight, I'll bet a Chevette and a Corvette are
> *producing* basically the same HP, even though there is a substantial
> difference in their maximum HP. ;-)
Just picking nits, the Corvette will be consuming more fuel because the
larger engine has more and larger bits rubbing together and thus more
friction. The difference will be small though.
> -- Mark
>
> P.S. Those who finished engineering degrees are invited to correct my
> mis/mal understandings. ;-)
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
In article <[email protected]>,
Duane Bozarth <[email protected]> wrote:
>George wrote:
>...
>> How about this:
>>
>> The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
>> causing the blade to bunch into the gap. Doesn't take much difference in
>> speed to start the process, which then increases in effect as the bunched
>> part slows....
>
>The upper wheel isn't free-wheeling, it's driven/pulled by the
>blade...the blade makes the wheel move, not the other way round...
On the other hand, the upper wheel has rotational inertia. It's an
interesting dynamics problem to figure out exactly what happens if you
get the whole system up to speed and then place drag on the
downward-moving blade.
"Old Nick" <[email protected]> wrote in message
news:[email protected]...
> Bob may have a point.
>
> ????????
One of the best writeups on motors I have seen on the internet is from our
very own rec.woodworking FAQ:
http://www.faqs.org/faqs/woodworking/motors/
Another good writeup is
http://www.engin.umich.edu/labs/csdl/ME350/motors/ac/induction/
Bob
On 20 Dec 2004 15:20:28 -0800, [email protected] wrote:
>Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
>it would be too much for my little BS.
No such thing as too much power on an electric motor - it won't go any
faster or need throttling, it'll just keep the speed up better under
load. It may even draw _less_ current than a smaller motor that's
having to work at it.
I wouldn't go out and buy a 2HP motor for a 14" bandsaw, but if you've
got it, you've no better use for it, the speed is right and you can
arrange the mountings and pulley, then go for it.
--
Smert' spamionam
On Thu, 23 Dec 2004 19:27:06 -0500, Nova <[email protected]>
calmly ranted:
>CW wrote:
>
>> No problem. 2horspower is still pretty weenie.
>
>It depends. Most 14" bandsaw have a problem providing enough tension for a
>3/4" blade without the frame flexing. Given a situation where a 2 HP motor
>would be beneficial, unless the saw was designed to handle that size motor,
>the frame of the saw would most likely flex, dropping the tension on the
>blade and result in a barreled cut. Hopefully that's the worse that would
>happen.
The motor horsepower shouldn't be of any concern (unless too small.)
I'd think the size of blade and the resultant tension required would
be the limiting factors.
>Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
>"no" on a 2 HP.
Did they say why? Were they saying no to the combo or to the larger
motor? My guess is the former, not the latter.
--
"Most Folks Are As Happy As They Make Up Their Minds To Be"
-Abraham Lincoln
-----------------------------------------------------------
www.diversify.com - Happy Website Development
On Fri, 24 Dec 2004 08:49:06 -0500, Nova <[email protected]>
wrote:
>Larry Jaques wrote:
>
>> Blade friction?!? The motor drives the lower wheel which drives the
>> blade and the upper wheel goes along for the ride. Whether you have
>> a 0.5 or a 5.0 hp motor should make little difference, since the
>> weight of the blade and upper wheel will be the same mass no matter
>> what motor.
>
>The blade friction is still there and has to be overcome. Unless the blade slips on
>the wheels the torque is taken by the frame. Think of it as pushing a rope which is
>the reason for barreled cuts.
but given that it's the same blade running at the same speed on the
same wheels, there is *no* difference.
now if you use that bigger motor as an excuse to jamb bigger pieces of
wood faster through a duller blade, yes you will be loading up the
frame. it'd be like putting a big block on a gocart. no problem at
idle, but floor it and the motor will tear itself free.
On Fri, 24 Dec 2004 11:57:37 -0600, Duane Bozarth
<[email protected]> wrote:
>Larry Jaques wrote:
>>
>...
>> The only part I can see being stressed by having a larger motor would
>> be the lower wheel (major) and its bearing (minor). Startup might be
>> quicker, creating higher initial (and inertial) stress, and it would
>> be able to do more work when making heavy cuts while resawing. The
>> upper wheel and frame are merely used as guides for the band.
>>
>> I just don't buy that C-frame flex thing at all. Wider bands and the
>> higher tension needed to run them would be the only cause of frame
>> stress that I can see. No, I take that back. The frame may have more
>> stress AT the lower wheel bearing mount during heavy cuts. The wheel
>> being slightly deflected upward up would also result in lower tension
>> on the blade, with the tension spring attempting to take up that
>> slack.
>>
>You've got it except you're overlooking the fact that the blade is
>pulling on the outside of the upper wheel which is applying torque to
>the frame...as the motor applies more power to the blade this gets
>transferred to a higher load which could in extreme case, cause the
>support to fail...
if your saw is *that* underbuilt just throw it away and buy a real
saw....
Yes.
"BillyBob" <[email protected]> wrote in message
news:[email protected]...
>
> "Duane Bozarth" <[email protected]> wrote in message
> news:[email protected]...
>
> > What a testament to the failure of science education in the general
> > populace (Bob, not you Nova)... :(
>
> Are you saying my statement was wrong?
>
> Bob
>
>
On Fri, 24 Dec 2004 14:26:16 -0700, [email protected] calmly ranted:
>On Fri, 24 Dec 2004 08:49:06 -0500, Nova <[email protected]>
>wrote:
>
>>Larry Jaques wrote:
>>
>>> Blade friction?!? The motor drives the lower wheel which drives the
>>> blade and the upper wheel goes along for the ride. Whether you have
>>> a 0.5 or a 5.0 hp motor should make little difference, since the
>>> weight of the blade and upper wheel will be the same mass no matter
>>> what motor.
>>
>>The blade friction is still there and has to be overcome. Unless the blade slips on
>>the wheels the torque is taken by the frame. Think of it as pushing a rope which is
>>the reason for barreled cuts.
>
>
>but given that it's the same blade running at the same speed on the
>same wheels, there is *no* difference.
>
>now if you use that bigger motor as an excuse to jamb bigger pieces of
>wood faster through a duller blade, yes you will be loading up the
>frame. it'd be like putting a big block on a gocart. no problem at
>idle, but floor it and the motor will tear itself free.
Yes, but only that portion of the frame which supports the driven
wheel bearing.
P.S: Jambs are for doors, not jammin' wood.
----------------------------------------------------------------------
* Scattered Showers My Ass! * Insightful Advertising Copy
* --Noah * http://www.diversify.com
----------------------------------------------------------------------
<[email protected]> wrote in message
news:[email protected]...
> Recently acquired a decent 2 hp 110/220a motor, and am now wondering if
> it would be too much for my little BS. Has anyone had any experience
> with big motors on small bandsaws? Would this be the funny car of the
> woodshop?
An electric motor HP rating is what its capable of putting out. If you do
not stress it, it does not produce any more HP than your existing motor. The
only way to make it produce the full 2HP is to really load it up. So you
are in control. Go for it.
Bob
On Fri, 24 Dec 2004 12:53:32 -0500, "George" <george@least> wrote:
>
>"Larry Jaques" <novalidaddress@di\/ersify.com> wrote in message
>news:[email protected]...
>> On Fri, 24 Dec 2004 08:49:06 -0500, Nova <[email protected]>
>> calmly ranted:
>>
>> >The blade friction is still there and has to be overcome. Unless the
>blade slips on
>> >the wheels the torque is taken by the frame. Think of it as pushing a
>rope which is
>> >the reason for barreled cuts.
>>
>> I think of it as the wheel pulling the teeth down, into the wood. The
>> majority of the tension on the blade is between the table and the
>> bottom wheel on the downward side. Since the wheels are connected,
>> there may be a very minor amount of "pushing", but the fact that the
>> band is laying on the -outside- of the wheels precludes much of that.
>> Any attempt at pushing would simply make space between the blade and
>> the wheel, and that could come only if there was no tension on the
>> blade at all. No, it is my understanding that barrel cuts are the
>> result of insufficient tension on the blade.
>>
>
>How about this:
>
>The free-wheeling upper wheel gets ahead of the driven, but loaded lower,
>causing the blade to bunch into the gap. Doesn't take much difference in
>speed to start the process, which then increases in effect as the bunched
>part slows....
>
the upper wheel is an idler and has less mass than the driven lower.
just how is it going to get ahead?
On Sun, 26 Dec 2004 11:38:23 -0500, Nova <[email protected]>
calmly ranted:
>Larry Jaques wrote:
>
>> Oh, so it's the stretching that causes the stress? <giggle>
>> You lost me with your last sentence. What part of synchronization
>> (other than the tension which puts them there) causes stress?
>
>The blade stretch takes place from the point of the bind to the drive wheel. Because the
>wheels attempt to move in sync the added length (along with the slop caused ny the slight
>compression of the tires and frame flex) is transferred around both wheels to the the top
>of the piece being cut. Although the blade isn't fixed to the frame other than being
>restricted by the piece being cut, think of the wheels as acting as the cams in a compound
>bow.
Close, but way different. The bow flexes when the bowstring is pulled
while the spring expands/releases when the blade is stretched. We're
talking opposites of your theory here. The equivalent on the bow is
the string, which remains at a fairly stable tension at or near the
rest position. Pull the string back 2" and you have the equivalent of
the bandsaw blade when the saw is turned off. Release the string and
you have the equivalent of the blade during a resaw, slightly less
tension and no bow flex.
The tension spring in the bandsaw takes up most of the slack and
removes the necessity to flex from the frame. Unless the spring is
bottomed out (full tension) or released (not involved), the frame
isn't stressed much more or less by stretch.
-------------------------------------------------------------
* * Humorous T-shirts Online
* Norm's Got Strings * Wondrous Website Design
* * http://www.diversify.com
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"J. Clarke" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote:
> Until it's big enough to break expensive things if something gets hung up
> bigger is better with motors. Now if you were talking 200 horsepower,
> which is enough to sling the whole saw through the roof if something goes
> awry, then I'd say maybe it was too much motor, but 2 should be fine on a
> 14". If it was one of the little bitty miniature hobbyist jobs I'd be
> worried about twisting off the drive axle or slipping the pulley, but a
14"
> unless it's a real piece of garbage should have no trouble with 2 HP.
Congratulations J. You clearly stated the case in way that anyone will
understand and my hat is off to you. While some of us are getting tangled
up in engineering design theory, you are came out and said what needs to be
said.
Bob
On Thu, 23 Dec 2004 20:36:43 -0500, Nova <[email protected]>
calmly ranted:
>Larry Jaques wrote:
>
>> On Thu, 23 Dec 2004 19:27:06 -0500, Nova <[email protected]>
>> calmly ranted:
>>
>> >CW wrote:
>> >
>> >> No problem. 2horspower is still pretty weenie.
>> >
>> >It depends. Most 14" bandsaw have a problem providing enough tension for a
>> >3/4" blade without the frame flexing. Given a situation where a 2 HP motor
>> >would be beneficial, unless the saw was designed to handle that size motor,
>> >the frame of the saw would most likely flex, dropping the tension on the
>> >blade and result in a barreled cut. Hopefully that's the worse that would
>> >happen.
>>
>> The motor horsepower shouldn't be of any concern (unless too small.)
>> I'd think the size of blade and the resultant tension required would
>> be the limiting factors.
>
>Blade friction. When you start resawing lumber where the power is needed a
>larger motor, say 2 HP will torque the frame. It will still pull the blade
>through the wood but with the flex the blade will "bunch up" above the drag. A
>smaller motor will stall before this happens. With my G1019 with the riser i got
>the distinct impression from Grizzly's tech support it would be risking snapping
>the frame with a 2 HP motor.
Blade friction?!? The motor drives the lower wheel which drives the
blade and the upper wheel goes along for the ride. Whether you have
a 0.5 or a 5.0 hp motor should make little difference, since the
weight of the blade and upper wheel will be the same mass no matter
what motor.
>> >Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
>> >"no" on a 2 HP.
>
>> Did they say why? Were they saying no to the combo or to the larger motor? My
>> guess is the former, not the latter.
>
>If you mean the combo of the G1019 and a 2 HP motor, yes the saw was designed
>for a 3/4 HP motor. I don't know if the riser kit figured in, but I imagine it
>would. The tech says a 1 HP wouldn't be a problem, 1.5 was questionable and 2
>HP was out.
No, I meant the wider blade and higher tension. But did you tell him
you'd be using low-tension Suffolk Timberwolfs? (Or were you?) How
much difference in mass could the longer/wider blade make? 8 ounces?
That slim margin would easily be quintupled by extra tension on the
original bandsaw with the original spring. Inertial mass _can't_ be
it.
--
"Most Folks Are As Happy As They Make Up Their Minds To Be"
-Abraham Lincoln
-----------------------------------------------------------
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On Fri, 24 Dec 2004 11:57:37 -0600, Duane Bozarth
<[email protected]> calmly ranted:
>Larry Jaques wrote:
>>
>...
>> The only part I can see being stressed by having a larger motor would
>> be the lower wheel (major) and its bearing (minor). Startup might be
>> quicker, creating higher initial (and inertial) stress, and it would
>> be able to do more work when making heavy cuts while resawing. The
>> upper wheel and frame are merely used as guides for the band.
>>
>> I just don't buy that C-frame flex thing at all. Wider bands and the
>> higher tension needed to run them would be the only cause of frame
>> stress that I can see. No, I take that back. The frame may have more
>> stress AT the lower wheel bearing mount during heavy cuts. The wheel
>> being slightly deflected upward up would also result in lower tension
>> on the blade, with the tension spring attempting to take up that
>> slack.
>>
>You've got it except you're overlooking the fact that the blade is
>pulling on the outside of the upper wheel which is applying torque to
>the frame...as the motor applies more power to the blade this gets
>transferred to a higher load which could in extreme case, cause the
>support to fail...
How could the inertial mass of the blade and aluminum wheel (under 10
pounds would be my highest guess) cause any more tension on the frame
than the tension adjustment spring, which is in the hundreds of
pounds? I still don't buy it, but I would like to hear the Griz
tech's explanation.
----------------------------------------------------------------------
* Scattered Showers My Ass! * Insightful Advertising Copy
* --Noah * http://www.diversify.com
----------------------------------------------------------------------
Larry Jaques notes:
>
>How could the inertial mass of the blade and aluminum wheel (under 10
>pounds would be my highest guess) cause any more tension on the frame
>than the tension adjustment spring, which is in the hundreds of
>pounds? I still don't buy it, but I would like to hear the Griz
>tech's explanation.
Me, too. But you've got to realize that Grizz is the one that still recommends
using a 20 amp fuse for an 18 amp machine because a 30 amp fuse might allow
damage to the motor. IIRC, and I'm not sure of this and can't find what I did
with the manual on the jointer, they try to make this a warranty issue. This
one wouldn't stand up anywhere, IMO.
Charlie Self
"Political language... is designed to make lies sound truthful and murder
respectable, and to give an appearance of solidity to pure wind." George Orwell
>
>>Larry Jaques wrote:
>>>
>>...
>>> The only part I can see being stressed by having a larger motor would
>>> be the lower wheel (major) and its bearing (minor). Startup might be
>>> quicker, creating higher initial (and inertial) stress, and it would
>>> be able to do more work when making heavy cuts while resawing. The
>>> upper wheel and frame are merely used as guides for the band.
>>>
>>> I just don't buy that C-frame flex thing at all. Wider bands and the
>>> higher tension needed to run them would be the only cause of frame
>>> stress that I can see. No, I take that back. The frame may have more
>>> stress AT the lower wheel bearing mount during heavy cuts. The wheel
>>> being slightly deflected upward up would also result in lower tension
>>> on the blade, with the tension spring attempting to take up that
>>> slack.
>>>
>>You've got it except you're overlooking the fact that the blade is
>>pulling on the outside of the upper wheel which is applying torque to
>>the frame...as the motor applies more power to the blade this gets
>>transferred to a higher load which could in extreme case, cause the
>>support to fail...
>
>How could the inertial mass of the blade and aluminum wheel (under 10
>pounds would be my highest guess) cause any more tension on the frame
>than the tension adjustment spring, which is in the hundreds of
>pounds? I still don't buy it, but I would like to hear the Griz
>tech's explanation.
>
>
Absolutely right. And, since it is torque and not power that determines the
pull exerted on the blade, I guess I have about a 10 horse motor on my 14"
Delta bandsaw.
Not really, of course. It's only 1 horse. But when I run it in the lowest
geared speed for cutting steel, it is putting as much torque to the wheel as a
10 horse motor would at wood cutting speeds. Maybe even more. And I'll
occasionally feed heavy steel pieces with enough force to slip the blade on the
lower wheel.
John Martin
In article <[email protected]>, J. Clarke wrote:
> One wonders if Grizzly even has an engineering staff. I suspect that the
> real engineers are not employed by Grizzly and speak little if any English
> and have never been within 5000 miles of the US.
I wouldn't put money on that "speak little if any English".
My wife stoped a pair of random young people in Nan Ning, CN
and asked them in English to take our picture. They both
spoke English quite well.
Charlie Self wrote:
> Larry Jaques notes:
>
>>
>>How could the inertial mass of the blade and aluminum wheel (under 10
>>pounds would be my highest guess) cause any more tension on the frame
>>than the tension adjustment spring, which is in the hundreds of
>>pounds? I still don't buy it, but I would like to hear the Griz
>>tech's explanation.
>
> Me, too. But you've got to realize that Grizz is the one that still
> recommends using a 20 amp fuse for an 18 amp machine because a 30 amp fuse
> might allow damage to the motor. IIRC, and I'm not sure of this and can't
> find what I did with the manual on the jointer, they try to make this a
> warranty issue. This one wouldn't stand up anywhere, IMO.
One wonders if Grizzly even has an engineering staff. I suspect that the
real engineers are not employed by Grizzly and speak little if any English
and have never been within 5000 miles of the US.
> Charlie Self
> "Political language... is designed to make lies sound truthful and murder
> respectable, and to give an appearance of solidity to pure wind." George
> Orwell
--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
In article <[email protected]>,
Nova <[email protected]> wrote:
> CW wrote:
>
> > No problem. 2horspower is still pretty weenie.
>
> It depends. Most 14" bandsaw have a problem providing enough tension for a
> 3/4" blade without the frame flexing. Given a situation where a 2 HP motor
> would be beneficial, unless the saw was designed to handle that size motor,
> the frame of the saw would most likely flex, dropping the tension on the
> blade and result in a barreled cut. Hopefully that's the worse that would
> happen.
>
> Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
> "no" on a 2 HP.
>
> --
> Jack Novak
> Buffalo, NY - USA
> (Remove "SPAM" from email address to reply)
The only time you really need the power and tension is when you're
resawing, and when you're resawing, there's usually very little material
on one side of the blade. So, it seems to me you could solve the frame
flexing problem by having a removable strut which could be fitted as a
compression member between the upper frame and the table when resawing.
I've never seen such a thing on a bandsaw, but I find it hard to believe
nobody else has thought of it before me. Does such a thing exist?
On Thu, 23 Dec 2004 20:12:00 -0500, Roy Smith <[email protected]> wrote:
>In article <[email protected]>,
> Nova <[email protected]> wrote:
>
>> CW wrote:
>>
>> > No problem. 2horspower is still pretty weenie.
>>
>> It depends. Most 14" bandsaw have a problem providing enough tension for a
>> 3/4" blade without the frame flexing. Given a situation where a 2 HP motor
>> would be beneficial, unless the saw was designed to handle that size motor,
>> the frame of the saw would most likely flex, dropping the tension on the
>> blade and result in a barreled cut. Hopefully that's the worse that would
>> happen.
>>
>> Grizzly's tech support was iffy on a 1.5 HP on my G1019 and had a definite
>> "no" on a 2 HP.
>>
>> --
>> Jack Novak
>> Buffalo, NY - USA
>> (Remove "SPAM" from email address to reply)
>
>The only time you really need the power and tension is when you're
>resawing, and when you're resawing, there's usually very little material
>on one side of the blade. So, it seems to me you could solve the frame
>flexing problem by having a removable strut which could be fitted as a
>compression member between the upper frame and the table when resawing.
>
>I've never seen such a thing on a bandsaw, but I find it hard to believe
>nobody else has thought of it before me. Does such a thing exist?
I was just thinking of such a thing for my performax 16/32.....
On Wed, 22 Dec 2004 04:13:56 GMT, "BillyBob"
<[email protected]> vaguely proposed a theory
......and in reply I say!:
remove ns from my header address to reply via email
hmmmm...having said that I have found a site that shows that motor
efficiency peaks at around 30% of full load. It shows a significant
blip there, then drops off steadily to 100% load / 80% efficiency.
Given that high efficiency motors are now being built using larger
conductors than necessary, Bob may have a point.
????????
>
>"Duane Bozarth" <[email protected]> wrote in message
>news:[email protected]...
>
>> What a testament to the failure of science education in the general
>> populace (Bob, not you Nova)... :(
>
>Are you saying my statement was wrong?
>
>Bob
>
"Greg O" <[email protected]> wrote in message
> I don't think you can have too much HP!
> Greg
If all the lights on your block dim when you turn on the saw, you have too
much horsepower.