You guys are probably right. What I'll do is put the riser block on without messing with a re-placement, shim for coplanar if it's only
1/8", put on a decent new blade, then see how she runs. Go from there.Good advice, both of you.
Thanks, H
I didn't say they don't deflect, I said that I can barely see any deflection. Big difference. These are hard tires. If there is little deflection, there is less ability to adjust to misalignment than with a soft tire.
You're avoiding the statement I'm making - the guys that are claiming that coplanar is not important don't have coplanar problems to begin with. BAD has a fancy BS that's only 1/16 out - the OP has one that's 3/8 out. I hope the lurkers are catching on to what's going on here - it's like a guy with a $300 LN or LV plane telling the guy with the $20 Footprint plane that sole flatness isn't an issue. Duh!
Ok then - what's level of adjustment is too anal? 0.001"? 1/16"? 1/3"? 3"?
I see the hand waving and lip flapping, but I'm asking for a real answer. If you or anyone else thinks that coplanar isn't an issue - then give us the real answer on what level of misalignment _is_ an issue so folks can judge how they're doing.
If you can't, then my answer is that you should do the best job you can at making it coplanar and don't ignore it - even if you think it's tracking reasonably. Why? For the same reason I spent a lot of time flattening the sole of an old Millers Falls plane I bought at a garage sale for $4
- because it's better that way!
Mike
Any amount that still allows the blade to track properly is acceptable. If my blade is cutting straight, making curves with east, re=sawing accurately, then it is close enough. I've not done any research nor have I owned many brands of saw to give you hard data. It either works, or it doesn't. Ed
Mike,
Here's why I think the coplaner thing doesn't matter if the misallignment is not too large:
Your ascii art suggests that the wheel (tire more specifically) is a cylinder. It's not. Properly formed tires have a crown. If the wheels are parallel but in different planes, the blade will ride in on one tire and out on the other (slightly). The inner surface of the band will still be tangent to the curve of the crown. Therefore there is no "twisting" of the blade. It is, however, running at a *very* slight angle to the table.
The crown of the tire not only allows tracking but mitigates any modest coplaner issues.
-Steve
I know that and addressed it in another post. However, I keep asking - What is "modest"? It's one thing to keep saying x amount of misalignment is ok, but no one wants to make a statement on what x is! If you phrase it like some do - "coplanar is nonsense" that's clearly wrong! However, making it perfect is not possible.
Edwin suggests that if it tracks, then the misalignment is not significant. On one level, I can accept that, but it still doesn't address whether you can make it track but still be stressing the blade more than necessary. Personally, I think you should make it as coplanar as possible - as I said, that's not hard to do.
Mike
I'm busted. I did not read the entire thread.
I'll go out on a limb and say 1/4". I think it is reasonable to assume that any new saw ought to be manufactured to within that tolerance... even "chiawanise junk". On older saws, I would suspect abuse.
No. i would not go quite that far. I would say that it's worth checking. If it's so far out that seriously effects tracking on new tires with a proper crown, I would call it a "defect" not and "adjustment".
significant.
Let me say this alittle differently: The blade is not twisting, It is riding normally, but in a *slightly* different axis. No twist = no additional stress.
I agree, It certainley can't hurt. I have a new bandsaw. I forgot to check it while the table was off, and chose not to bother once I found that everything tracked well. Maybe I'm just lucky. BTW it was ade in Taiwan.
Cheers
-steve
Why? Based on what?*
I don't see why they can't make a bandsaw that's better than that even if assembled by demented monkeys. Even in the days before assembly lines and standardized parts they could make things better than that!
Unisaw claims his is out of alignment and _doesn't_ run on a different axis. Two different stories. Which one is correct?
Put two wheels out of alignment by 5 inches and try to get them to run a blade without twisting. Now tell me how you know that, oh... 2" will ride flat without twisting. How about 0.5"? You're making an assumption based on thinking that the tires will magically account for any out-of-plane error. I agree that they _can_ correct for some degree of misalignment, but I don't know how much and I'm not going to guess. I do know that the crown on the tires on my BS are large radius and I doubt it can handle a big misalignment without twisting.
I'm still waiting for the "myth of the coplanar" crowd to come up with some facts instead of opinions. We already know they're misquoting and misinterpreting Duginske. They still can't come up with anything to quantify their claims.
Mike
Hey Michael,
How come all your posts are hidden on the web google NG? All I see is what Edwin includes in his posts.
Curious, H
No idea - but I noticed that my posts contain: X-No-Archive: Yes. I don't know if google uses that to decide whether to include or not. I changed it to No and see if that fixes it.
Mike
That is indeed the case. Google honors the X-No-Archive header.
scott
But... but...
What fun would *that* be?
;-)
djb
For starters, I do not own a band saw and I do not recall ever using one. There have been times when I wished I had one, but got along somehow without buying one.
In reading this thread from the beginning, It has occurred to me that it might be possible to put one or more washers on one side or the other of one of the wheels - say the top wheel if it is not driven. Could the remedy of the out of coplanar situation be as simple as that?
Hoyt W.
as long as you've got a whopper of large hole in your washers.
dave
Hoyt Weathers wrote:
Yep, that was it. Now we both know.
H.
Geometry.
You are reinforcing my point that out of coplaner by more than the "fudge factor" is a major DEFECT, not a setup issue withing the normal parameters of adjustment.
I will not speak for unisaw.
That is what any reasonable person would call a defect. My assertion was that a perperly manufactured saw could handle a "modest" (which I have defined) non-coplaner situation
No magic. The geometry of crowned tires as explained above.
It is a function of the radius of the crown. Granted, tough to compute accurately, because it should be done as a function of the crown under tension (rubber sightly compressed), but I think eye-balling it is good enough to show that it works.
With axels 48" apart, 1 degree equals just inder an inch of fudge factor.
e.g. tan(a)= fudge/angle
Later I will take some accurate measurements of the crown and comute the actual angular change associated with the proposed 1/8th inch shift.
Hi Hoyt,
Yes, shimming with washers is the common way to go. [Dave: your average 5/8" hardware store variety work fine on Deltas and clones.]
My first measurement, which was a 3/8" out-of-alignment wheel (and which measurement turned out to be wrong), made it impractical to fix with shims since the bearing shaft on the upper wheel has only so much room before you run out of thread for the nut.
In addition, I didn't like the idea of a half-ass workaround to fix alignment that was that far off; if I could get the thing aligned at the frame level that would be better, and since I was putting on a riser block anyway why not try to fix it then.
I have, owing mostly to this thread, realized that may be more difficult than I had imagined, but I had the good fortune of realizing that my alignment was not out 3/8", but only 1/8", so shimming is not so onerous, if necessary at all.
H.
Why? I can't help but think you're making this up as you go along.
Defect or not, it still comes into play. If someone has a defective BS, the advice they get on the wreck is not "get the manufacturer to replace your BS", it's "Don't worry, coplanar isn't an issue."
You're not following. At what point does the crown cease to correct the blade effectively?...
Ahh, you do know conceptually.
By eye, I can barely detect any compression on my tires. The radius seems large and even a small error in assumptions will have a large effect on the result. We're not talking about large angles here - eyeballing it won't help...
Can anyone realistically eyeball less than one degree? I know that most folks can't judge angles worth a damn.
But it still relies on your 1/8 assumption. A good start if you can justify that. Better than anyone else has done so far.
Mike
Because that's what tracking adjustment *IS*. Adjusting where the blade runs on the tire. Tires are generally a little bigger than the largest recommended blade size.
Yes, if it's new and it it grossly non-coplaner replace is the most appropriate advise. If it's modestly non-coplaner it probably does not effect the ctting ability of the saw. If it's used and grossly out if whack.... shim where you can to get it close.... then it's no linger an issue.
Huh?
No, but the width an height of the crown can be measured. The radius of the crown can be calculated from that measurement, and what I call the fudge factor can calculated from radius and blade shift. My point was that a very subtle angular change caused by a blade shift results in a comparatively large distance in "fudge factor" because that small angular change is measured over the distance between the axels (3 or 4 feet)
I can. For my saw. The tires are 1-3/8", max blade 1"... that's 3/16ths either way. YMMV
Ok, that's acceptable. Not for my BS, though. It's a chiwanese quasijunk model and the tires are narrow, almost flat and yet they say I can use a
1" blade. The tire is barely 1" wide. It will likely still allow for tracking adjustment, but with little or no rubber outside of the blade.I agree - can we nail this advice into the foreheads of unisaw, BAD and the other "coplanar is a myth" crowd?
Much wider than mine - hence a difference in view between me and you. The replacement tires I've seen have all been narrow too. What BS is yours?
Mike
It's so nice watching the kids play.
UA100
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