Subject: Re: Bandsaw Problem

From: [email-masked] (Robert Galloway)
Date: 28 Mar 1997 07:30:50 -0700

>Ernie,
>
>Others have mentioned how important blade tension is and I agree, put
>more tension on the blade than is suggested. I don't know how your saw
>shows how much tension is on the blade but tighten it more than it is
>supposed to have. Crank it up. Use a pipe wrench if it gets hard to
>turn by hand. (within some sense of reason of course)
>
>After you have the guides aligned very close to the tight blade
>capturing all of the blade but the hook of the teeth, and raise the
>guides to just above the piece to be resawn, (shorten your fence if
>necessary) the blade has no choice but to follow.
>
>theoretically of course.
>
>Al

To each his own, but I don't think I'd use a pipe wrench to add blade 
tension.  I hate to join in the "go to the library" admonition but I 
don't have the "rule of thumb" with me.  Mark Duginske (sp?) has an 
excellent book on the care and feeding of bandsaws and if the tension 
indicator on your saw isn't up to snuff or it lacks one altogether, he 
will give you the technique for measuring sideways deflection to get the 
correct tension.  In my limited experience, the band is the most 
important factor.
I resaw, usually, 6" x 4/4 material which I plane to two 6 x 3/8 pieces.  
I have a tall fence which I always set at 90 degrees to the table edge. 
I have a a 1/2" 4 tpi hook tooth band that will track straight end to end 
and top to bottom.  When I have been too lazy to change the band and 
tried to resaw with the 1/4" blade that's usually on the saw, I get a 
complete mess.  Ergo, my impression that the band is the thing.  I'm not 
saying that 1/2 vs 1/4 is the factor, I would guess I've messed up the 
set or otherwise buggered up the smaller bands so that they don't track 
well.  The advice about setting the blocks to fully support the band, I 
think is good, at least that's what I try to do.  I think that 
overtensioning the band might flex the saw and actually exacerbate the 
problem.  Good luck.  Let us know what you find that works.

rhg

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From: Nancy Lenz <[email-masked]>
Date: Wed, 26 Mar 1997 19:28:10 -0600

Al Taylor wrote:
> 
> >Ernest Shipley wrote:
> >>
> >> I have an old bandsaw and it cuts good for curves, etc., but I have a
> >> real problem trying to resaw with it. If I resaw stuff more than 3"
> >> thick  I can't keep the blade from wondering around. I've done all the
> >> "book tuning" I can think of. I use a tall fence. The blade seems to
> >> always want to go to the side the fence is on no matter which side I put
> >> it on. I've done the saw halfway thru thing and lined the fence up on
> >> the mark but doesn't seem to help. I am now using 1/2"-3tpi skip tooth
> >> blade by PS Wood. Anybody got any suggestions other than get a new one
> >> |:) ?
> >> Ernie
> 
> Ernie,
> 
With a pipe wrench.What kind of trash advice is this?
Mike Bridges
[email-masked]

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From: Kit Davidson <[email-masked]>
Date: Fri, 28 Mar 1997 16:15:51 +0000

In article <[email-masked]>, Robert Galloway
<[email-masked]> writes
>problem.  Good luck.  Let us know what you find that works.
Your blade is wandering because it is trying to bend backwards as the
wood is pressured against it. A sharp blade will cut, a blunt blade will
twist and make a concave cut when it is restrained from bending
backwards by the roller guides. Obviously, a blade will also behave like
this if the feed rate is too high, no matter how sharp it is. Also the
width of the blade is a factor, a blunt wide blade will distort while
cutting before a thinner blade in the same conditions. I never use
blades wider than .25ins and find the skip variety has a bettr all round
performance for resawing. I also recommend Mark Duginske's book, `The
Bansaw Handbook', I was as baffled as you until I read it!
-- 
Kit Davidson

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From: [email-masked] (Al Taylor)
Date: Sat, 29 Mar 1997 02:22:19 GMT

>With a pipe wrench.What kind of trash advice is this?

Mike, 

I know it probably sounds extreme, but the tension handle on my
bandsaw is so small and hard to turn that it is necessary to use
something of length to get enough torque to turn it even a little past
the recommended setting. 

It's not really trash advice at all, I'm just saying  -  use whatever
means necessary to do the job, whether it's by hand or with a pipe
wrench, or whatever.

BTW more tension, IS better.

Al

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From: [email-masked] (Al Taylor)
Date: Sat, 29 Mar 1997 08:16:08 GMT

I really appreciate all the advise about the bandsaw, personally I'm
not having any trouble with my bandsaw, (I keep my blade nice and
tight) I was responding to another person's problem with their
bandsaw. 

Ernest was having trouble with his bandsaw. He has a 1/2" 3tpi skip
tooth blade, had read a book about tuning his bandsaw and done what he
read and was still having trouble getting a straight cut on anything
taller than 3 inches (resawn).

Now, if you've done all that and still can't get it to cut straight
the one thing that comes to mind is the blade tension. The tension
mark on the bandsaws are just the starting point, if the blade is
still wandering after all the guides are set and the bearings are set
you need to increase the blade tension. Don't be afraid of hurting
your bandsaw it can take a reasonable increase in tension over the
suggested mark. 

If the tension knob, handle or whatever gets hard to turn by hand use
whatever is handy to give it that extra twist, even God forbid....a
pipe wrench. 

The blade tension that cuts just fine on 2 inch thick stuff might not
be enough when you raise the guides to resaw taller stuff. If your
bandsaw resaws just fine with the amount of tension you have on it
now, put that pipe wrench down.

thanks again

Al

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From: [email-masked] (Tom J.)
Date: Fri, 28 Mar 1997 22:48:48 GMT

Robert Krecak <[email-masked]> wrote:

>There are many things to check on a bandsaw. First make sure ALL the
>bearings are in good shape. If any of the support bearings on either of
>the wheels are loose when the edges are moved in and out they must be
>replaced or the wheels will spin inconsistently. Use a precision
>straightedge and check if the faces of the wheels are on the same plane.
>If not the lower wheel is usually moved in or out on the belt shaft.
>Check the blade guides to make sure they are properly adjusted. Remember
>the blade must be properly tracked and tensioned BEFORE  the guides are
>adjusted. Check the tires on the wheels for dirt, grit, etc. Use a new
>blade, sometimes the set is off causing wandering. I adjust my
>guideblocks so there is about 3-4 thousandths of an inch between them
>and the blade total.

>Bob Krecak

Ernie:

I have had the same problem and could never re-saw well usin the
fence.  I made a pair of guides by attaching 6" long pieces of 3/4
dowl to some 3/4 plywood.  One guide I attache to the fence, the other
I clamp to the table.  I set the guides to have the smallest distance
beween the dowls just in front of the blade with just enough room for
my stock to slide between them.  I then scribe a line on my board to
follow. I can now re-saw with no problem as I move the the board
slightly to compensate for the blade wanting to track to one side.  I
am sure others have a better way but this works for me.  I have trid
to provide a sketch to demonstate my setup but it will need some
imagination on your part.

      Blade      II
         I           II
===O O====II
        II          II
        II          II< Fence
        II
    Board

Tom

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From: [email-masked] (David Roseman)
Date: Sat, 29 Mar 1997 16:44:15 GMT

On Sat, 29 Mar 1997 08:16:08 GMT, [email-masked] (Al Taylor)
wrote:

> The tension

Al, experienced bandsaw users might know to chuckle at your advice in
a previous post that "more tension is better" and in this post to
"give it that extra twist" with a pipe wrench, but many users might
not.  Your qualification of your  advice with the admonition to do
this "within reason" and to leaves the reader with no objective
parameters, and the advice really becomes useless, if not dangerous.
Even on a quality light-commercial-duty saw like the Delta 14",
serious damage to the bandsaw wheel axles can occur if even a 1/4"
blade is significantly overtensioned.   A good-quality conventional
1/4" blade can take something like 30,000 psi before breaking, way
more tension than a homeshop bandsaw is designed to handle.  A 1/2"
blade can take far more tension still.  Overtensioning is a
prescription for equipment failure. Ten years ago, Fine Woodworking
published an article on bandsaw blade tensioning by a then-associate
editor.  For a 14" two-wheeled bandsaw like the Delta with a 6" riser
block, he recommended tuning both bimetal and carbon steel 1/4" blades
to the musical note "G" for serious resawing and to "E" as adequate
for general all-around.   This corresponds to about 27,500 psi and
15,000 psi, respectively.  (The 1/4" setting on the little scale that
comes with the  Delta saw reportedly produces between 2,500 and 12,000
psi, depending on how new the spring is).  Many readers tried
super-tensioning in the G range and reported that they'd never gotten
such great cuts with their saws.  Then axles started shearing off.
Delta and others began reporting a dramatic increase in axle and
bearing failures due to excessive tension.  For awhile they replaced
the axles just as a matter of customer relations.  While I'm not
certain of it, I believe the author departed the FWW staff shortly
thereafter in part as a result of the controversy.  To connect this up
to your posts, tension in the 25,000 psi range with a 1/4" blade is
easily achieved on a Delta or Delta-clone 14" bandsaw without a
pipewrench.  This is way beyond the design limitations.  I don't know
what kind of bandsaw you have, but if you have trouble getting enough
tension without a pipe wrench something sounds seriously wrong.  Also,
you might want to try one of the "low tension" silicon steel blades
manufactured by Suffolk Machinery Corp in Patchogue, New York.
800-234-7297 for a catalogue.  PS Machines (I think others) sells the
same blades in blister packs for alot more money than factory direct.
These blades claim to produce better cuts at lower tension than
conventional blades.  dcr

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From: [email-masked] (Pat Thaler Bill Thomas Jared Thaler Leor Thomas Avi Thomas)
Date: Mon, 31 Mar 1997 18:43:21 GMT

Greetings,

I tightened the blade on my Delta 14 per Suffolk's instructions and 
found the tension pointer pointed to the same mark, i.e. blade size,
as the blade size. In other words, following either Delta's or Suffolk's
advice produced the same result on  a relatively new Delta 14. Since age
will not affect the results of Suffolk's advice, I will use it
to re-calibrate the Delta scale for each new blade.

Sincerely,
Bill Thomas
/*============================================================================*/
David Roseman ([email-masked]) wrote:
: On Sat, 29 Mar 1997 08:16:08 GMT, [email-masked] (Al Taylor)
: wrote:

: > The tension
: >mark on the bandsaws are just the starting point, if the blade is
: >still wandering after all the guides are set and the bearings are set
: >you need to increase the blade tension. Don't be afraid of hurting
: >your bandsaw it can take a reasonable increase in tension over the
: >suggested mark. 
...
: to your posts, tension in the 25,000 psi range with a 1/4" blade is
: easily achieved on a Delta or Delta-clone 14" bandsaw without a
: pipewrench.  This is way beyond the design limitations.  I don't know
: what kind of bandsaw you have, but if you have trouble getting enough
: tension without a pipe wrench something sounds seriously wrong.  Also,
: you might want to try one of the "low tension" silicon steel blades
: manufactured by Suffolk Machinery Corp in Patchogue, New York.
: 800-234-7297 for a catalogue.  PS Machines (I think others) sells the
: same blades in blister packs for alot more money than factory direct.
: These blades claim to produce better cuts at lower tension than
: conventional blades.  dcr