As far as I can tell, there are only two thrust bearings, one on the
guides above the table and one on the guides below, and they both contact
the side of the blade. A quick peek at the parts list and exploded
diagram seems to confirm this. Am I missing something?
On Sun, 25 Jan 2004 02:48:02 +0000, MSgeek wrote:
They should barely (dollar bill thickness) almost be touching the back of
When the saw is on and not cutting they should not spin. When the saw is
cutting they should be spinning. They support the rear of the blade. What
model is the saw?
Ah, I see... I had the thrust bearings against the *side* of the blade,
but it makes more sense against the back. The thrust bearing supports the
rear, not the guide block holder....
forgive me, i'm learning :) Fortunately, it was a relatively inexpensive
It's a G1012, btw
On Sun, 25 Jan 2004 03:39:14 +0000, MSgeek wrote:
Whatever I can find hanging on the wall :)
We have two bandsaws, one's an old packard precision 14", that's not
operational for whatever reason, and we have this big grizzly 18" that we
actually use. It normally spends its days with a tiny 1/16" blade on it,
but I really wanted to resaw some tiger maple that I bought and bookmatch
it, so I dug through the pile of blades on the wall and found a nice 1"
hook tooth blade and put it on. I managed to get the resaw I wanted done
just as the guide block holder fell in half :P I have no clue what brand
blade it is, but I could take a picture of it for you :) There are a
bunch of blades out there, some are small, for the packard I guess, and
there's a few of the big 124" blades that the grizzly takes.
Fortunately, grizzly's already shipping me a new guide block holder, as
well as some spare blocks, since it's missing two on the bottom guide.
(hm, come to think of it, there's a metal bandsaw back in the back of the
shop under a pile of junk and dust, one of the ones where you can tilt the
blade horizontal if you want. I should pull that thing out and see what
it can do)
On Sun, 25 Jan 2004 06:39:52 +0000, MSgeek wrote:
Would guess the blade was WAY under tensioned, and as you re-sawed the
blade bowed BACK into the and rubbed it away
Not sure what the specs on that specific blade are, but would bet it
wants to be around 20,000-30,000 psi tension which is pretty hard to
achieve on many saws
Yes, to all 3, but let's hope your first one actually comes first. After a bit,
too, you get used to plinking the thing with a fingernail to check tension.
Supposedly, you can also use a tuning fork, but I'm tone deaf.
"Character is much easier kept than recovered." Thomas Paine
I can't see how a tuning fork would help much unless you know what note
you're aiming for, and I would well expect that the target note is going to
vary with the thickness, width and other qualities of the blade. Maybe I'm
missing the point, and the objective is to get every blade, no matter the
type, to plink the same?
Not that I have a bandsaw anyway, mind you. Well, not a woodworking
bandsaw. The rule I use on my metal cutter is when I can't turn the knob
any further without some sort of cheater, it's tight enough.
Michael McIntyre ---- Silvan < firstname.lastname@example.org>
Linux fanatic, and certified Geek; registered Linux user #243621
No, rather the opposite.
What you're aiming for is to set tension / area as a constant. Tuning
forks measure tension, so you need a different "ping" for each blade
The easiest, and most accurate, thing to measure is strain (stretch)
which is constant for all blades of the same alloy.
Use a tension gauge and set it to whatever the blade maker suggests
Other than shorter lifespan of the blade, there is not much really
wrong with running a blade with more tension than it actually needs,
as long as the saw FRAME will handle the tension, AND you release the
tension after use
Also, if you fully compress the blade tension spring, that is a bad
idea. Spring completely compressed has NO give to absorb shocks/etc
On Sun, 25 Jan 2004 07:29:23 -0500, "Stephen Meier"
On Sun, 25 Jan 2004 07:29:23 -0500, "Stephen Meier"
It doesn't - the bandsaw ought to cope with more tension than the
blade, so for best results ask the blade, not the frame.
A cheap 14" saw ought to tension 1/2" blades and track 3/4" blades.
You'll get better results from a 1/2" blade at the right tension than
from an under-tensioned 3/4". Fitting a better spring can sometimes
To be honest, there is no point in running a blade more than 1/2" wide
on a "domestic" 14" saw. You might have to look harder to find the
tooth profile you want in a narrower band, especially for huge hook
teeth to rip green timber, but it'll work better.
The limit of tensioning a bandsaw is when you bottom out the spring.
The frame itself ought to take a huge amount of tension, far more than
the blade will ever need, but most 14" machine springs can't tension a
With the spring in proper use, it acts as a shock absorber. If you've
squashed the spring flat, then there's no "give" in the saw, should
the blade catch on anything. The spring rate goes up and so the
slightest change in length causes a huge increase in tension - this
snaps your blade or damages the wheel bearings.
Blade tension is best measured by measuring length extension (strain)
in the blade itself. Strain (length change) is more important than
stress (force). Measure this accurately at least once for each blade
(redo it as the blades age), then calibrate your own saw for your own
favourite blades. Most saws have a tension scale which is inaccurately
calibrated, but you can make your own marks on it.
To saw well, we would like to use an enormous tension (force) to
stress the blade. However the blade is also a spring, so this applied
stress gives rise to a resultant strain (stretching). Too much strain
in any steel causes fatigue, and this depends more consistently on the
_strain_ achieved, not the stress. We thus reduce the tension on the
blade until the strain is reduced enough to give an adequate blade
lifetime. Properly run, blades should break from fatigue just as
their teeth are worn out.
The simplest strain meter was described in FWW some time back. Take a
6" stick with one end sawn off and sliding loose on a headless nail
(effectively a stretchy stick). Take the tension off the blade and
clamp the closed-up stick to it at 5" centres. Now tension the blade
and watch the gap open up in the stick (You can knock a couple of pins
in to give a pair of measuring faces). Measure this gap with feeler
gauges. A maximum strain of 0.1% equates to a 5 thou gap over 5" of
blade length, which is a reasonable figure.
The pictures are in FWW 147 - Jan/Feb 2001. But ignore the text,
because it's ignorant gibberish (You can't measure tension in psi,
and it goes downhill from there 8-( )
Some makers (Suffolk's Timberwolf) specialise in blades that are
designed to run at a lower strain. Refer to their documentation for
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