Why no 3-wheel bandsaws?

On 15 Jan 2004 14:14:16 -0800, [email protected] (Garrett)
wrote:

>I admit, I have that little Grizzly 3 wheeler. It's awful to set up,
>I can't get the table square to the blade, and if the blade slips off
>the wheel only once each time I use it, I feel pretty lucky. The
>access panel isn't hinged, so you have to take the whole side off each
>time you need to get inside, which is quite annoying. Also, the
>little feet on the bottom aren't square to each other or the saw body.
> I haven't broken any blades yet, but I have the speed set as low as I
>can to help keep the blade on the wheels, while still being able to
>manage making my cut. I wouldn't even DREAM of using it to resaw
>anything; it only has 3 5/16" cutting height anyway, regardless of
>what the website claims. In all, I'd say it was a waste of my 140
>bucks plus whatever the shipping was. FWIW



I wonder if it would be more useful as a band sander than as a band
saw....

On 14 Jan 2004 09:41:33 -0500, DJ Delorie <[email protected]> wrote:

>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,

No, it's subject to 3/2 as much.

It's bending the blade to fit the wheel, or straightening it
afterwards that represents the stress cycling, not just the total
bending angle (which is always going to be 360°)

--
Do whales have krillfiles ?

"Mark Jerde" <[email protected]> wrote in message
news:[email protected]...
> Bay Area Dave wrote:
> > good question. I just checked in "Bandsaw Handbook" by Mark Duginske.
> > He said that early 3 wheelers had small diameter wheels that stressed
> > the blades. He mentions that even with larger wheels the blade life
> > is shorter. No explanation of this phenomenom is given.
>
> I made it to 2/3 rd's of a Mechanical Engineering degree before switching
to
> Computer Science. The only possible explaination I can think of in 4
> minutes of cerebration is that the number of bends per blade revolution is
> significant. Suppose you had two bandsaws, each with 15" wheels. One has
> two wheels, the other 3. The two wheels model would subject the blade to
> two bends per revolution. The three wheeled bandsaw would have 3 bends
per
> rev of the blade. Maybe it is not so much how long the blade is curved
> around the wheel but how many times you change its straightness. The
answer
> is beyond my knowledge one way or the other.
>
> -- Mark

DINGDINGDINGDING!!!! We Have a Winner, Folks!

That is exactly why the three wheel BS blade break faster. The fatigue is
created from the flexing of the blade BOTH onto and off off the wheel,
therefore you are absolutely correct that the blade on a 2 wheeler will have
150% the life of the 3...all other things being equal, of course.

Mike

On 13 Jan 2004 20:36:15 -0800, [email protected] (Hylourgos) wrote:

>A simple question: why aren't bandsaws more commonly made with three
>wheels instead of two? Sure, I've seen custom jobs made that way, and
>the fact that 2 is more simple than 3 is obvious, but the tradeoff for
>cutoff and height capacity seems worth it, but I don't know of any
>popular manufacturers making them.
>
>There must be a good reason...anyone know?
>
>Curiously,
>H



big 3 wheelers have a big footprint.
they have to have a much stiffer frame.
the tighter radius is hard on the blades.

On 13 Jan 2004 20:36:15 -0800, [email protected] (Hylourgos) wrote:

>A simple question: why aren't bandsaws more commonly made with three
>wheels instead of two?

There are decent three wheelers around, but not many. If you see
something like an Inca close up, it's huge.

One of the advantages of a two-wheel bandsaw is that it takes up very
little workshop space relative to its capacity, being neatly arranged
in a vertical stack.
--
Do whales have krillfiles ?

I have one of the older 16" Delta 28-560. It is a well built, sturdy saw
that works great for small projects. It requires thinner (018" -.020")
blades as well as a 1/2" max blade width. As a result the saw does not resaw
very well. Most sawdust encrusted people need a saw that does both.

I really like having them both. The Delta with a 1/8" blade for quick and
sharp corners and my new (very happy with) 16" Jet with a 1" resaw blade.

As compared to the standard 14" two wheeler, the 28-560 is built heavier
than current models and I'm sure it, by today's standard, would cost as much
or more to manufacture.

If you have room, find one and enjoy.

Dave

"Andy Dingley" <[email protected]> wrote in message
news:[email protected]...
> On 13 Jan 2004 20:36:15 -0800, [email protected] (Hylourgos) wrote:
>
> >A simple question: why aren't bandsaws more commonly made with three
> >wheels instead of two?
>
> There are decent three wheelers around, but not many. If you see
> something like an Inca close up, it's huge.
>
> One of the advantages of a two-wheel bandsaw is that it takes up very
> little workshop space relative to its capacity, being neatly arranged
> in a vertical stack.
> --
> Do whales have krillfiles ?

Grizzly makes a small one

http://www.grizzly.com/products/item.cfm?itemnumber=G8976




"Hylourgos" <[email protected]> wrote in message
news:[email protected]...
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>
> There must be a good reason...anyone know?
>
> Curiously,
> H

Jeffo wrote:
>
> "Hylourgos" <[email protected]> asked
> news:[email protected]...
> > A simple question: why aren't bandsaws more commonly made with three
> > wheels instead of two? Sure, I've seen custom jobs made that way, and
> > the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> > cutoff and height capacity seems worth it, but I don't know of any
> > popular manufacturers making them.
> >
> > There must be a good reason...anyone know?
> >
> > Curiously,
> > H
>
> My father had one... for about a day, please don't make me think about it.=)
> I can't remember who it was made by, likely Trademaster, smaller bench top
> size. The blade was a pain to set up, just when we thought it was ready to
> go, it would come off one of the wheels. Maybe it was ignorance, maybe a
> problem with the machine, bad design could is an option, you do get what you
> pay for, but that just can't justify everything. All I know is that he
> replaced it with a 14" 2 wheel and hasn't looked back.
>
> HTH,
> Jeffo

I started with a Black/Decker 3 wheel bandsaw years ago. I broke a blade
almost every time I used it. I also burned up many moters. I always took
it back to the store and they gave me a new one. I finally got tired
buying new blades. They usually broke at the solder joint. I guess heat
and bending caused this. My Delta 14" has never caused me a problem and
has never broken a blade. My 2 cents!! Chuck B.

Blades break when they're flexed repeatedly. They are flexed each time
they pass over a wheel.

JK


Joel Jacobson wrote:
>
> > ... why aren't bandsaws more commonly made with three wheels instead of
> two?
>
> There are three wheel bandsaws. They have at least two serious
> disadvantages: it's really hard to align the wheels and keep them aligned.
> Also, the blades tend to break much easier.

On Monday, March 4, 2019 at 5:24:27 PM UTC-5, Leon wrote:
> On 3/4/2019 9:30 AM, [email protected] 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).
> >=20
> > You are right both 2 and 3 wheel blades go through the the same 360 deg=
rees of bending during each revolution and the degree of bend for each whee=
l 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.
> >=20
>=20
> 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 re: space, other than black or white, 2 wheeler
or 3.

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

Mark Jerde said:

>Hylourgos wrote:

>> There must be a good reason...anyone know?
>
>ISTM it's harder to get three wheels in the same identical plane as two. I
>think that's the primary issue.

Blade fatigue is the big reason-in addition to manufacturing expense.


Greg G.

On Tuesday, January 13, 2004 at 9:36:15 PM UTC-7, Hylourgos wrote:
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>=20
> There must be a good reason...anyone know?
>=20
> Curiously,
> H

Hard as it might be to believe; the big manufacturers don't KNOW how to des=
ign a three-wheeled saw. They haven't even solved the first problem: making=
a drive wheel adjustable for tracking. Most of them haven't figured out ho=
w to combine tension and tracking in the same assembly. The "leading" manuf=
acturers won't invest a penny in research or development because you bought=
the idea: "if it ain't broke........" So band saws are generally the wors=
t designed tool in the box. I make the kind of saw you'd love to have but y=
ou can't afford it and I can't afford it either. Big corporations don't "DO=
" niche market products like mine because they're expensive to build (not e=
nough profit). I do, but I'm not as "popular"

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, [email protected] 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 re: space, other than black or white, 2 wheeler
> or 3.
>
> http://www.ana-white.com/2015/12/free_plans/flip-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.

On Monday, March 4, 2019 at 10:30:37 AM UTC-5, [email protected] 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.
> >=20
> > 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).
>=20
> You are right both 2 and 3 wheel blades go through the the same 360 degre=
es 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 o=
n 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=20
bends are sharper on a 3 wheeler. Sure, the degree of bend is less on a=20
3 wheeler than a 2 wheeler *if* the wheels are the same size, but I don't=
=20
think that "same size" is typically the case.

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

http://www.northfieldwoodworking.com/bandsaws/50throat.htm

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.
>=20
> 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.

On 14 Jan 2004 12:36:14 -0500, DJ Delorie <[email protected]> wrote:

>If it's bending the same number of times each minute,

It isn't.

It's 3/2 the bending per cycle, but the bending per minute depends on
the band length (and the speed). A large bandsaw always gets better
band life, simply because it's spreading the load between more band.

--
Do whales have krillfiles ?

On 14 Jan 2004 17:41:29 -0500, DJ Delorie <[email protected]> wrote:

>And if you read my original email, you'll note that I specified that
>the distance between the wheels remained constant,

But how can the distance between the wheels remain constant in
switching between a 2 and 3 wheeled machine ?

A tricycle is either going to have tiny wheels (band breakers) or it's
going to have the same wheels, same spacing and an extra long band
(long band, long life). Presumably there's a point somewhere in the
middle where band life is equal for the same cut performance, but
you'd have to estimate the increase in fatigue with decreasing radius
to calculate it.

--
Do whales have krillfiles ?

Well, anytime you run something across three items versus two there is more
friction, thus more blade wear and fatigue. Make sense?

Jim


"Mark Jerde" <[email protected]> wrote in message
news:[email protected]...
> Greg G. wrote:
> > Mark Jerde said:
> >
> >> Hylourgos wrote:
> >
> >>> There must be a good reason...anyone know?
> >>
> >> ISTM it's harder to get three wheels in the same identical plane as
> >> two. I think that's the primary issue.
> >
> > Blade fatigue is the big reason-in addition to manufacturing expense.
>
> Why would there be blade fatigue if you used the same diameter wheels?
All
> the 3-wheel bandsaws I've seen use smaller wheels but ISTM this is a
> decision, not a requirement.
>
> -- Mark
>
>

I have both, though the 3 wheeler is for sale.
The 3 wheeler goes through blades faster, due to stress of smaller diameter
wheels and thinner baldes but has always tracked OK,even after 16 years of
(ab)use...
2 wheelers are cheaper to manufacture. Less parts, easier to manufacture as
3rd idler wheel isn't there.
The 3 wheelers are usually 'benchtop' units,semi portable while 2 wheelers
are floor mounted beasts.
hth
jay

Why would you want to have 3 wheels when 2 will do?

Try COST being the determining factor.

"Hylourgos" <[email protected]> wrote in message
news:[email protected]...
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>
> There must be a good reason...anyone know?
>
> Curiously,
> H

Hylourgos wrote:
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>
> There must be a good reason...anyone know?
>
> Curiously,
> H

ISTM it's harder to get three wheels in the same identical plane as two. I
think that's the primary issue.

-- Mark

"Chuck B." <[email protected]> wrote in message news:<[email protected]>...
> Jeffo wrote:
> >
> > "Hylourgos" <[email protected]> asked
> > news:[email protected]...
> > > A simple question: why aren't bandsaws more commonly made with three
> > > wheels instead of two? Sure, I've seen custom jobs made that way, and
> > > the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> > > cutoff and height capacity seems worth it, but I don't know of any
> > > popular manufacturers making them.
> > >
> > > There must be a good reason...anyone know?
> > >
> > > Curiously,
> > > H
> >
> > My father had one... for about a day, please don't make me think about it.=)
> > I can't remember who it was made by, likely Trademaster, smaller bench top
> > size. The blade was a pain to set up, just when we thought it was ready to
> > go, it would come off one of the wheels. Maybe it was ignorance, maybe a
> > problem with the machine, bad design could is an option, you do get what you
> > pay for, but that just can't justify everything. All I know is that he
> > replaced it with a 14" 2 wheel and hasn't looked back.
> >
> > HTH,
> > Jeffo
>
> I started with a Black/Decker 3 wheel bandsaw years ago. I broke a blade
> almost every time I used it. I also burned up many moters. I always took
> it back to the store and they gave me a new one. I finally got tired
> buying new blades. They usually broke at the solder joint. I guess heat
> and bending caused this. My Delta 14" has never caused me a problem and
> has never broken a blade. My 2 cents!! Chuck B.


It has alot to do with traction.....you don't get as much with less
blade contact on three wheel saws as with 2 wheel saws. I bought an
Amada saw once that could cut 36" thick steel 12 foot long on a power
feed table, The capacity was an issue at the time. I asked about three
wheel saws and the Amada people explained about blade traction and
blade life.

The saw took a blade 1/8" x 2 5/8" x 19' 11"

John

On 13 Jan 2004 20:36:15 -0800, [email protected] (Hylourgos) brought
forth from the murky depths:

>A simple question: why aren't bandsaws more commonly made with three
>wheels instead of two? Sure, I've seen custom jobs made that way, and
>the fact that 2 is more simple than 3 is obvious, but the tradeoff for
>cutoff and height capacity seems worth it, but I don't know of any
>popular manufacturers making them.
>
>There must be a good reason...anyone know?

From what I've heard, the blades break every dozen
revolutions or so due to the small wheels and tight
radius. It stresses the metal too much for longevity.


----------------------------------
VIRTUE...is its own punishment
http://www.diversify.com Website Applications
==================================================

On Tuesday, January 13, 2004 at 9:36:15 PM UTC-7, Hylourgos wrote:
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>=20
> There must be a good reason...anyone know?
>=20
> Curiously,
> H
Popular manufacturers don't know how to build three wheels that work becaus=
e they barely know how to keep a two wheeler working. They didn't know how =
to apply a simple lever-action to the tensioner until I introduced the conc=
ept in 2003. They don't how to combine tension and tracking in one assembly=
and they still haven't even figured out how to track their drive wheels. T=
hey DO know that such saws would be expensive; a niche. The big box stores =
couldn't sell them because you wouldn't buy them. =20

> ... why aren't bandsaws more commonly made with three wheels instead of
two?

There are three wheel bandsaws. They have at least two serious
disadvantages: it's really hard to align the wheels and keep them aligned.
Also, the blades tend to break much easier.

I admit, I have that little Grizzly 3 wheeler. It's awful to set up,
I can't get the table square to the blade, and if the blade slips off
the wheel only once each time I use it, I feel pretty lucky. The
access panel isn't hinged, so you have to take the whole side off each
time you need to get inside, which is quite annoying. Also, the
little feet on the bottom aren't square to each other or the saw body.
I haven't broken any blades yet, but I have the speed set as low as I
can to help keep the blade on the wheels, while still being able to
manage making my cut. I wouldn't even DREAM of using it to resaw
anything; it only has 3 5/16" cutting height anyway, regardless of
what the website claims. In all, I'd say it was a waste of my 140
bucks plus whatever the shipping was. FWIW


"David Clarke" <[email protected]> wrote in message news:<[email protected]>...
> Here's one: http://www.grizzly.com/products/item.cfm?ItemNumber=G8976
>
> "Hylourgos" <[email protected]> wrote in message
> news:[email protected]...
> > A simple question: why aren't bandsaws more commonly made with three
> > wheels instead of two? Sure, I've seen custom jobs made that way, and
> > the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> > cutoff and height capacity seems worth it, but I don't know of any
> > popular manufacturers making them.
> >
> > There must be a good reason...anyone know?
> >
> > Curiously,
> > H

On 13 Jan 2004 20:36:15 -0800, [email protected] (Hylourgos) wrote:

>A simple question: why aren't bandsaws more commonly made with three
>wheels instead of two? Sure, I've seen custom jobs made that way, and
>the fact that 2 is more simple than 3 is obvious, but the tradeoff for
>cutoff and height capacity seems worth it, but I don't know of any
>popular manufacturers making them.
>
>There must be a good reason...anyone know?
>
>Curiously,
>H

Duginski's book talks about this. Three-wheel machines are more
difficult to tune, more expensive to make, and blades wear out faster.
Better to have a large two-wheeler than a small three-wheeler with the
same capacities.

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

> 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).

180 x 2 = 360
120 x 3 = 360
However, it is still flexed 3 times per revolution rather than only two. It
is probably the more total flexes rather than the amount it is flexed each
time. Perhaps a metallurgist can be more detailed in this.
Ed

Mark Jerde said:

>Greg G. wrote:

>> Blade fatigue is the big reason-in addition to manufacturing expense.
>
>Why would there be blade fatigue if you used the same diameter wheels? All
>the 3-wheel bandsaws I've seen use smaller wheels but ISTM this is a
>decision, not a requirement.

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.


Greg G.

On Thu, 15 Jan 2004 01:55:58 +0000, Andy Dingley
<[email protected]> wrote:

>On 14 Jan 2004 17:41:29 -0500, DJ Delorie <[email protected]> wrote:
>
>>And if you read my original email, you'll note that I specified that
>>the distance between the wheels remained constant,
>
>But how can the distance between the wheels remain constant in
>switching between a 2 and 3 wheeled machine ?
>
>A tricycle is either going to have tiny wheels (band breakers) or it's
>going to have the same wheels, same spacing and an extra long band
>(long band, long life). Presumably there's a point somewhere in the
>middle where band life is equal for the same cut performance, but
>you'd have to estimate the increase in fatigue with decreasing radius
>to calculate it.




cheap benchtop 3 wheel bandsaws aside, big 3 wheel saws generally have
2 wheels top and bottom and a third bigger wheel somewhere way back
there to open up the width. it makes for a large expensive saw
usually requiring a pretty specialized process to justify it.
Bridger

good question. I just checked in "Bandsaw Handbook" by Mark Duginske.
He said that early 3 wheelers had small diameter wheels that stressed
the blades. He mentions that even with larger wheels the blade life is
shorter. No explanation of this phenomenom is given.

dave

Mark Jerde wrote:

> Greg G. wrote:
>
>>Mark Jerde said:
>>
>>
>>>Hylourgos wrote:
>>
>>>>There must be a good reason...anyone know?
>>>
>>>ISTM it's harder to get three wheels in the same identical plane as
>>>two. I think that's the primary issue.
>>
>>Blade fatigue is the big reason-in addition to manufacturing expense.
>
>
> Why would there be blade fatigue if you used the same diameter wheels? All
> the 3-wheel bandsaws I've seen use smaller wheels but ISTM this is a
> decision, not a requirement.
>
> -- Mark
>
>

On 11/12/2017 4:43 PM, [email protected] wrote:
> On Tuesday, January 13, 2004 at 9:36:15 PM UTC-7, Hylourgos wrote:
>> A simple question: why aren't bandsaws more commonly made with three
>> wheels instead of two? Sure, I've seen custom jobs made that way, and
>> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
>> cutoff and height capacity seems worth it, but I don't know of any
>> popular manufacturers making them.
>>
>> There must be a good reason...anyone know?
>>
>> Curiously,
>> H
> Popular manufacturers don't know how to build three wheels that work because they barely know how to keep a two wheeler working. They didn't know how to apply a simple lever-action to the tensioner until I introduced the concept in 2003. They don't how to combine tension and tracking in one assembly and they still haven't even figured out how to track their drive wheels. They DO know that such saws would be expensive; a niche. The big box stores couldn't sell them because you wouldn't buy them.
>

IDIOT

--
Jeff

On 3/4/2019 9:30 AM, [email protected] 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

"Hylourgos" <[email protected]> asked
news:[email protected]...
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>
> There must be a good reason...anyone know?
>
> Curiously,
> H

My father had one... for about a day, please don't make me think about it.=)
I can't remember who it was made by, likely Trademaster, smaller bench top
size. The blade was a pain to set up, just when we thought it was ready to
go, it would come off one of the wheels. Maybe it was ignorance, maybe a
problem with the machine, bad design could is an option, you do get what you
pay for, but that just can't justify everything. All I know is that he
replaced it with a 14" 2 wheel and hasn't looked back.

HTH,
Jeffo

On 3/4/2019 11:00 AM, pyotr filipivich wrote:
> [email protected] 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"...

--

On 3/4/2019 7:58 PM, pyotr filipivich wrote:
> dpb <[email protected]> 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...

--

[email protected] 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.
--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?

Willy Wanka wrote:
> Why would you want to have 3 wheels when 2 will do?

You can have a deeper throat, and it can sit on a bench.
http://www.grizzly.com/products/item.cfm?itemnumber=G8976

-- Mark

dpb <[email protected]> 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:
>> [email protected] 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?

Here's one: http://www.grizzly.com/products/item.cfm?ItemNumber=G8976

"Hylourgos" <[email protected]> wrote in message
news:[email protected]...
> A simple question: why aren't bandsaws more commonly made with three
> wheels instead of two? Sure, I've seen custom jobs made that way, and
> the fact that 2 is more simple than 3 is obvious, but the tradeoff for
> cutoff and height capacity seems worth it, but I don't know of any
> popular manufacturers making them.
>
> There must be a good reason...anyone know?
>
> Curiously,
> H

"Edwin Pawlowski" <[email protected]> writes:

> "DJ Delorie" <[email protected]> wrote in message
> news:[email protected]...
>
>> 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).
>
> 180 x 2 = 360
> 120 x 3 = 360
> However, it is still flexed 3 times per revolution rather than only
> two.

But with the conditons above one complete blade revolution takes
longer because the third wheel in that configuration requires a longer
blade,

--
Dr. Juergen Hannappel http://lisa2.physik.uni-bonn.de/~hannappe
mailto:[email protected] Phone: +49 228 73 2447 FAX ... 7869
Physikalisches Institut der Uni Bonn Nussallee 12, D-53115 Bonn, Germany
CERN: Phone: +412276 76461 Fax: ..77930 Bat. 892-R-A13 CH-1211 Geneve 23

Andy Dingley <[email protected]> writes:
> No, it's subject to 3/2 as much.
>
> It's bending the blade to fit the wheel, or straightening it
> afterwards that represents the stress cycling, not just the total
> bending angle (which is always going to be 360°)

If it's bending the same number of times each minute, how is that 3/2
the stress then?

"Edwin Pawlowski" <[email protected]> writes:
> However, it is still flexed 3 times per revolution rather than only two.

At the same RPM, each "revolution" takes 1.5 times as long. The
number of flexes *per minute* is the same, for a given linear FPM
speed of the blade.

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).

Andy Dingley <[email protected]> writes:
> It's 3/2 the bending per cycle, but the bending per minute depends on
> the band length (and the speed).

And if you read my original email, you'll note that I specified that
the distance between the wheels remained constant, as did the motor
RPM and wheel diameter.

Bay Area Dave wrote:
> good question. I just checked in "Bandsaw Handbook" by Mark Duginske.
> He said that early 3 wheelers had small diameter wheels that stressed
> the blades. He mentions that even with larger wheels the blade life
> is shorter. No explanation of this phenomenom is given.

I made it to 2/3 rd's of a Mechanical Engineering degree before switching to
Computer Science. The only possible explaination I can think of in 4
minutes of cerebration is that the number of bends per blade revolution is
significant. Suppose you had two bandsaws, each with 15" wheels. One has
two wheels, the other 3. The two wheels model would subject the blade to
two bends per revolution. The three wheeled bandsaw would have 3 bends per
rev of the blade. Maybe it is not so much how long the blade is curved
around the wheel but how many times you change its straightness. The answer
is beyond my knowledge one way or the other.

-- Mark

Greg G. wrote:
> Mark Jerde said:
>
>> Hylourgos wrote:
>
>>> There must be a good reason...anyone know?
>>
>> ISTM it's harder to get three wheels in the same identical plane as
>> two. I think that's the primary issue.
>
> Blade fatigue is the big reason-in addition to manufacturing expense.

Why would there be blade fatigue if you used the same diameter wheels? All
the 3-wheel bandsaws I've seen use smaller wheels but ISTM this is a
decision, not a requirement.

-- Mark