Not only do we have the train off the tracks but it's
careening down the embankment, towards the combo
orphanage/old folks home/puppy and kitty adoption agency.
A band saw, a "properly" designed band saw, has a wheel.
Into this wheel fits a shaft. This shaft and wheel fit into
a bearing directly behind the wheel. This wheel, shaft and
bearing fit into a cast iron housing where the bearing is
seated. At the other end of the cast iron housing the shaft
protrudes but before it protrudes we have another bearing
also seated into the housing.
What we have here is a cantilever, or, more appropriately
for this point and for this argument, a fulcrum and lever (a
see-saw Dave). The first bearing, right behind the wheel,
is the fulcrum. The wheel shaft acts as the lever.
Still with me? If not then grab your saw manual and take a
gander at the es'ploaded parts drawing.
OK, as I've already confessed I'm no injineer but what I do
know from experience and that is, any force being applied
down onto the top of the wheel by the band is transferred
and exerted onto the shaft which in turns puts a great deal
(tremendous actually) of downward force onto the first
bearing (the fulcrum).
The back bearing, it's got it's hand full with the upward
force being exerted by the lever (shaft).
Now, with all of this going on inside your poor band saw, do
you really want to peddle the myth of co-planar and bearing
So, co-planar will allow me to buy and use the crappiest
blades? Can anyone recommend a good crappy blade?
Ummm, the wheels, they don't give a rat's rosy red rectum
about co-planar. They already have their hands full with
the job they were designed to do.
Angled Table Saw Fences
PVC Causing Dust Collector Fires
The Lumber Car
How many more of these myths do we have floating around?
10,000 nuns and orphans ...... They were all eaten by rats.
The leg bone's connected to the
The ankle bone's connected to the
I just don't get all the "Oh my god, think of the poor bearing!"
wailing and beating of breasts. For a given blade, there's only
one "alignment" of the wheels which is correct: the one where the
blade tracks properly. My bearings will just have to suffer with
whatever that means.
You explode your band saw parts? Hmmm... I'm starting to
side more with the bearing.
This comes up every week on the wreck. DAGS, lazy bones.
Aren't those rats supposed to be rancid?
Doug, where are you?
I don't know about myths, per se, but the electrical threads
often contain some real thigh slappers/side splitters.
How about "real woodworkers never stain cherry"?
The From: header above is wrong on porpoise
You may not be an engineer, but I are.
If the wheels aren't coplanar, the crowns of the wheels don't
line up. The blade isn't going to ride on the centre of the
crowns by itself. If it's centred on one crown, it's riding
the edge of another and it will tend to wander off. Only
if the crowns are aligned will the blade run on both crowns
with minimal strain.
Once coplanar, you tension the blade and the force on the
wheels tends to pull them out of plane. You adjust the top wheel
to bring them back more-or-less into line. That's the tracking
If you start with non-coplanar, you'll likely have problems with
tracking unless you start torquing everything around to make up
Lining it up coplanar is an easier way to start out. YMMV.
In theory this is true but as I have said, my wheels aren't
co-planar and the band(s) ride(s) as true as anything I've
OK, "maybe" someone could check it with some snot, boogers
and a stick (or a TS Aligner Jr.) and find it out by half a
thou but so far this gross alignment isn't an issue.
OK, I think I've found the crux of the biscuit. Define what
you mean by minimal? Are you saying there's always strain
no matter the alignment? Even in a perfect world? Sorry, I
know the answer to this. I'm baiting you. OK, there, I
OK, we know this to be true. And we should add, that the
given make-up of every blade is different and therefore each
and every blade will have a different effect on the wheels?
OK, we know this to be true.
But, but, my wheels aren't co-planar and my band(s) ride(s)
right down true and center on the wheels. I'd be happy to
open up my shop to any wreckreite who would like to ponder
this problem (or stand in awe as they gaze upon it) with me
or who doesn't believe me or who would like to further their
studies on the subject. But in the mean time, I still say
you're all blowing smoke up a rat's rosy red (and rancid)
rectum to say it's worth any more time than to note it,
i.e., don't get your undies inna bunch over it.
After snipping lots of wind, I add:
How about angled wheels? When ya adjust so the blade will ride in the
center, you adjust the tilt of the top wheel from the vertical plane
(trying to SOUND) like an engineer here).
Wottehell, this will have some effect, too. Real effect, not
You tension the blade and the wheels tilt in. You tilt the top wheel
out to realign. This makes them parallel again at the expense of
a slight change away from coplanar. As I said in another message,
you can get away with a _slight_ misalignment.
I once tried adjusting the saw so that it's coplanar even under tension.
This is an iterative approach that means adjust, tension, check, detension,
readjust, tension, check, detension, readjust, tension, check...
until the alignment is "perfect" under tension. It didn't work
significantly better than the conventional alignment but was a _lot_ more
work and the adjustments were different for each blade. The reason is
that all that fiddling doesn't make a lot of change in the actual alignment.
Coplanar - the easy way to get good alignment. Non-coplanar - maybe it'll
work if you're lucky and/or you don't care much about the resulting cutting
In article <slQWb.36507$TPZ.12451
Believe me, you can get away with gross misalignment if you have a
forgiving blade and a good crown on the tires.
While this might help you sleep better at night, you're spending way too
much time on this. The bottom line is that if the blade tracks well
while under tension and torsional loads, you got a winner.
It's kinda like tuning up a 65 Mustang. You throw out the book and go
And while Duginske is a good read, he puts too much emphasis on coplanar
wheels. He should have spent time teaching the masses how to crown a
Pretty broad brush there Mikey. Do you have scientific evidence to
prove this? Seems to me my non coplanar saw cuts just fine, thank you.
And, I *do* care about cutting quality and blade life.
Just remember - it's wood, not platinum.
Welcome. I know what you mean about those pesky bandsaurs - even the
old arn ones. No matter how hard I try, no matter how much I spend on
blades, no matter how much time I spend with my trusty TS-Aligner Jr
(tmEB) and straightedge, I can't get those glue ready edges!
I go slow, no love. I speed up, no love. New bearings and tires, no
love. I adjust the positioning of the saur relative to true magnetic
north, still no love.
Surely, there is some book or infomercial that can save us!
I'm hoping that Mikey will be at the Mahwahkee WW show next week so he
can show me (and the boys at Laguna) how to do it the right way.
Rick, willing to make 3 easy payments of $29.95 so I can get rid of my
jointer, planer, and sandpaper...
(Remove the HIGH SPOTS for e-mail)
For blades of different size - yes. For blades of the same size
and make - negligible.
Either the alignment isn't bad (even though you haven't changed
anything since you bought it) or the amount of crown + the
tension + other stuff is forcing your blade into some stressful
I've done a bit of experimenting with the amount of alignment
(easy, since the one I have came 1/4" out of coplanar!) and
you can make it work while slightly out of alignment. But
if properly aligned, you get good tracking and less blade
Maybe you're not fussy about the quality of the cut.
The problem is the movement of the force from the flat
of the bearing area to the edges of the bearings. Auto
engineers moved to tapered roller bearing pairs to
overcome the longevity problem and angular loading.
(I read all about that in wrenchin' school 30 yarn ago.)
Co-linearity is one of those items the engineers push
for. It probably makes a difference only in long-term
use in heavy production environments. But why NOT try
to set it on your home machine? It can only make the
beastie run better. Ditto link-belts. They made a helluva
difference on my Griz. My neighbor lost a large branch
off one his madrones in the wind a couple weeks ago and
I'm going to see if I can get some lengths to resaw. I
love the look of that wood.
I don't buy the "coplanar" argument. The goal is to have the
blade track correctly. My common-as-dirt Delta 14" tracks
correctly when the wheels are not coplanar. There's even an
adjustment to change the plane of the upper wheel in order
to correct any problems with the blade not tracking right.
I was at a Scott Phillips demo a few months back. He said the same thing.
You have to get the blade tracking on the top of the wheel just right. He
is a fan of high tension for resawing in spite of what Timberwolf says.
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