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Default Why no 3-wheel bandsaws?

On Wednesday, January 14, 2004 at 9:41:33 AM UTC-5, DJ Delorie wrote:
Greg G. writes:
Every time you bend the blade around a wheel, it results in fatigue.
Eventually, the constant bending and straightening of the blade
results in breakage.


If the wheels are the same size and distance apart, and the motor RPM
the same, the blade is subject to the exact same bend/straight
cycling, so there should be no more fatigue than with only two wheels.
In fact, there may be less because the blade is bent for a shorter
time each time it bends (120 degrees around instead of 180).


You are right both 2 and 3 wheel blades go through the the same 360 degrees of bending during each revolution and the degree of bend for each wheel is less on a 3 wheel unit. However There are still 3 bend/straight cycles on a 3 wheel and only 2 on a 2 wheel.
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Default Why no 3-wheel bandsaws?

dpb on Mon, 4 Mar 2019 12:33:23 -0600 typed in
rec.woodworking the following:
On 3/4/2019 11:00 AM, pyotr filipivich wrote:
on Mon, 4 Mar 2019 07:30:34 -0800 (PST) typed
in rec.woodworking the following:
On Wednesday, January 14, 2004 at 9:41:33 AM UTC-5, DJ Delorie wrote:
Greg G. writes:
Every time you bend the blade around a wheel, it results in fatigue.
Eventually, the constant bending and straightening of the blade
results in breakage.

If the wheels are the same size and distance apart, and the motor RPM
the same, the blade is subject to the exact same bend/straight
cycling, so there should be no more fatigue than with only two wheels.
In fact, there may be less because the blade is bent for a shorter
time each time it bends (120 degrees around instead of 180).

You are right both 2 and 3 wheel blades go through the the same 360 degrees of bending during each revolution and the degree of bend for each wheel is less on a 3 wheel unit. However There are still 3 bend/straight cycles on a 3 wheel and only 2 on a 2 wheel.


And on a 3 wheel bandsaw, there's one more set of wheel, axle,
bearings, etc to add to the machine.


But you get more throat clearance for the given length of blade...and in
some 50 years, I've yet to have a BS blade fail by "fatigue"...


Yep. OTOH, it does take up more bench space.

And from a manufacturers perspective: how much can they save by
not having that third wheel?

--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?


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Default Why no 3-wheel bandsaws?

On Monday, March 4, 2019 at 10:30:37 AM UTC-5, wrote:
On Wednesday, January 14, 2004 at 9:41:33 AM UTC-5, DJ Delorie wrote:
Greg G. writes:
Every time you bend the blade around a wheel, it results in fatigue.
Eventually, the constant bending and straightening of the blade
results in breakage.


If the wheels are the same size and distance apart, and the motor RPM
the same, the blade is subject to the exact same bend/straight
cycling, so there should be no more fatigue than with only two wheels.
In fact, there may be less because the blade is bent for a shorter
time each time it bends (120 degrees around instead of 180).


You are right both 2 and 3 wheel blades go through the the same 360 degrees of bending during each revolution and the degree of bend for each wheel is less on a 3 wheel unit. However There are still 3 bend/straight cycles on a 3 wheel and only 2 on a 2 wheel.


However, as far as I know, the wheels on a bench-top 3 wheeler are always
smaller than the wheels on your typically 2 wheeler. That means that the
bends are sharper on a 3 wheeler. Sure, the degree of bend is less on a
3 wheeler than a 2 wheeler *if* the wheels are the same size, but I don't
think that "same size" is typically the case.

Unless of course, you are talking about one of these. ;-)

http://www.northfieldwoodworking.com...s/50throat.htm
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Default Why no 3-wheel bandsaws?

On 3/4/2019 7:58 PM, pyotr filipivich wrote:
dpb on Mon, 4 Mar 2019 12:33:23 -0600 typed in
rec.woodworking the following:

....


But you get more throat clearance for the given length of blade...and in
some 50 years, I've yet to have a BS blade fail by "fatigue"...


Yep. OTOH, it does take up more bench space.


Not than a saw with equivalent throat depth, though, methinks...



And from a manufacturers perspective: how much can they save by
not having that third wheel?


But they can provide larger capacity saw for less than the full-blown
frame I'll bet...

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Default Why no 3-wheel bandsaws?

On 3/4/2019 8:26 PM, DerbyDad03 wrote:
On Monday, March 4, 2019 at 5:24:27 PM UTC-5, Leon wrote:
On 3/4/2019 9:30 AM, wrote:
On Wednesday, January 14, 2004 at 9:41:33 AM UTC-5, DJ Delorie wrote:
Greg G. writes:
Every time you bend the blade around a wheel, it results in fatigue.
Eventually, the constant bending and straightening of the blade
results in breakage.

If the wheels are the same size and distance apart, and the motor RPM
the same, the blade is subject to the exact same bend/straight
cycling, so there should be no more fatigue than with only two wheels.
In fact, there may be less because the blade is bent for a shorter
time each time it bends (120 degrees around instead of 180).

You are right both 2 and 3 wheel blades go through the the same 360 degrees of bending during each revolution and the degree of bend for each wheel is less on a 3 wheel unit. However There are still 3 bend/straight cycles on a 3 wheel and only 2 on a 2 wheel.


https://woodgears.ca/bandsaw/3-wheeled.html


One of these could negate his "moving it around/less space efficient"
argument. Just saying. I'm not defending 3 wheelers, just noting that
there's another option space, other than black or white, 2 wheeler
or 3.

http://www.ana-white.com/2015/12/fre...top-tool-stand

Ultimately the 3 wheelers end up having smaller wheels, in most of the
cases, and as you pointed out the tighter bend is the problem.
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