Advice before I put on riser block? (Coplanar attempt too...)

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That sounds right to me - the starting point is a coplanar bandsaw. I haven't argued for anything else. Screwing around with a wildly ooc bandsaw is a good way to waste a lot of time.

Splitting hairs isn't going to solve anyone's problems. If making it coplanar requires a gazzillion dollar widget and several days to get it perfect, there's a perfectly reasonable expectation that folks will balk. However, using a straightedge and aligning it accordingly is a reasonable attempt at making it coplanar. If you're still out by 1/8" or more, then you probably shouldn't be using a bandsaw.
Mike
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You aren't by any chance the fellow that goes by George Preddy in the digital photo NG are you? He is a Foveon fanatic who's posted OVER 3,500 posts on the merits of that sensor over Bayer sensors which are used in Canons, et al. This coplanar thing is gonna become your legacy.
Go have a beer and relax, Michael...
dave
Michael Daly wrote:

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Beats having your reputation, BAD boy.
Mike
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I'm not so sure about that. I must have SOME entertainment value; witness the undo attention I receive from the likes (or more to the point, the ilk) of TW.
dave
Michael Daly wrote:

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wrote:

cf: "whack-a-mole".
cf: "plagues of egypt".
cf: "children of israel".
cf: "kant tried to determine a rational basis for the inclusion of irrational beings into the polis - he was unsuccessful". (op cit ref JOlP, v. 4, Letter 12.3).
cf: "turds float".
Thomas J. Watson-Cabinetmaker (ret) Real Email is: tjwatson1ATcomcastDOTnet Website: http://home.comcast.net/~tjwatson1
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did you notice I said my hard drive crashed and I'm starting up the filtering again. you aren't on it yet, buddy boy.
dave
Tom Watson wrote:

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snipped-for-privacy@magma.notthis.ca says...

No doubt - I'm sure everyone would prefer to start off with a pristine bandsaw within all MFG tolerances. In reality, probably ain't gonna happen.

Mike, isn't splitting hairs what engineers do? :-) I tried to point out the contradictory choice of words. Similar *does* actually mean different, doesn't it?
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Regards,

Rick

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Um, no.
Mike, as a digital professional (I R 1), sometimes it's it easy to forget the leave the discrete world or 1's and 0's and return to the real (in the mathematical sense) world. There is no such thing in the real world as straight, flat, perpendicular, flat or coplaner. If you think it is, then you need a better measuring tool. Even light bends.
Common usage of "straight" really means "straight enough" or "relatively straight". The same thing goes for "coplanar".
I would submit that in the context of woodworking, "similar" at least as often as not *does* mean "same".
As a "software engineer", I am invoking the right bestowed upon me by my employer and the State (University) of New York, to split that baby right down to the follicle :-)
-Steve
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snipped-for-privacy@primelink1.net says...

Steve,
I think you made my point. :-)
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Rick

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Michael Daly:

Well I'll be damned. It must be true. I mean, look up, there it is.
UA100
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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
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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
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wrote:

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".

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
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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
* My BS came out of the factory with around 1/4" error and did track. Didn't cut well, but it did track. YMMV
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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.
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But... but...
What fun would *that* be?
;-)
djb
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as long as you've got a whopper of large hole in your washers.
dave
Hoyt Weathers wrote:

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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.

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wrote:

2. There should be enough extra space on a tire for the blade to shift at least 1/8". 3. draw a line tangent to the crown of the blade at a position 1/8" off center. This will "point" more than 1/4" out of the axis of the wheel. This is the "fudge factor" of non-planer acceptability
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.

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.

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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
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