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

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read every word. let's just agree to disagree.
dave
Michael Daly wrote:

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Disagree on what? Your comments had absolutely nothing to do with what I wrote!
Mike
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that's why I continue to disagree with your assessment of a "problem". NOW do you get it, Michael?? ") Nice try though and as someone more profound that myself has said many times, "thanks for playing". NOW can we drop this non-argument? 'Cause if YOU don't drop it, you'll be arguing with yourself next.
dave
Michael Daly wrote:

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Would it? You are assuming the blade is going to track on center of the bottom wheel, but what if it does not?
I was at a Scott Phillips demo about bandsaw setup and he dismissed the co-planer thing also. To him, tracking the top wheel and proper tension is needed for true running. Ed
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I make no such assumption. The blade will ride on the part of the tire that allows it to come into equilibrium with the forces on it. But unless the curvature of the tire match _exactly_ to the degree of out-of-plane, the blade will be twisted.

I'm talking about stress on the blade.
Imaging someone telling you that a frame in a car doesn't have to be straight. They drive around with a bent frame and think everything is fine. They say the auto engineers don't know anything about cars and body shops that straighten frames are ripping people off. Does that make it ok to have a bent car frame? Is that in turn the same as saying that no one should have a straight frame?
Just because you can make it work, doesn't mean that it's all right. I like to see things running square and true. You can true your equipment with a sledge hammer for all I care, but don't tell me it's right. It's not like aligning the bandsaw wheels is a big deal - it takes a few minutes. If you have that much trouble with it, are you sure this is the hobby for you?
If out of plane is ok, how much is ok? 1/4"? 1/2"? 2"? 10"? Let's hear some facts about this out-of-plane acceptability.
Mike
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I can tell you aren't into empirical testing, are you Michael? Instead of using JUST logic, you should do some TESTING of your hypothesis. Then you would undoubtedly change your tune.
dave
Michael Daly wrote:

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DAGS on this ng and you'll likely find a coupla posts where I explained my tests.
Change my tune? To what? Any old bandsaw adjustment is ok and who cares?
Mike
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I'm not saying that one should not carefully adjust the guides and set the blade to track near the center of the top wheel, but the coplanar "thing" is really much ado about nothing. The wheels of my Powermatic are about 1/16" out of being perfectly aligned, when under tension for a 5/8" blade. The blade runs true, quietly, and cuts fine. When I shim the upper wheel so that it is truly coplanar while under tension, then the blade doesn't track nearly as well due to the slight tilt of the upper wheel. I see no gain in messing with the factory set-up of the BS. I DO pay VERY particular attention to setting the Carter guides "by the book", so to speak. And all is well with my bandsawing operations... To suggest that I am not picky about setting up my equipment is a laugher.
dave
Michael Daly wrote:

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Or the tire will flex to match the blade.

I'm not saying no one SHOULD have coplaner, but you don't necessarily HAVE to have it to be operating properly. Plenty of cars on the road do have frames not aligned.

I don't know as I've not done any testing. My saw seems to be very close and hte blade tracks just fine so I'm not going to change anything, nor will I do any more checks of it unless a problem occurs. What I am interested in is a perfect cut. As long as I get that, the rest is just a bother. Ed
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You must have awfully mushy tires. I can barely see any deflection in the surface of mine. They're crowned, but kinda flat (i.e. long-radius curvature) too. Behavior with a 1/4" blade will be very different than that of a 3/4". I put more faith in coplanar than in some undefined capacity of the tires to fix any potential stress problems in a blade that's running at over 10,000psi and a couple of thousand feet per minute!

I read somewhere that engineers keep their cars in better condition than the average driver. I wonder why? I'm an engineer and I tend to prefer to keep things set up well and running well. But then I don't have unlimited faith in the materials we use in our world.

Every time this comes up, the guys that say it's unimportant eventually admit that they have a BS that's fairly true or is a high-end model that's quite true out of the factory. But the guys asking the questions about coplanar have the chiwanese quasijunk that is way out of adjustment and performs accordingly.
Open question remains - if out of plane is acceptable, what are its limits? If no one can answer that with a realistic answer, then I'll stick with the folks like Duginske who actually know what they're talking about.
Mike
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Most tires are a rubber compound. Rubber compounds are usually designed to deflect or move in some manner or they would just use steel or aluminum. Must be a reason. As an engineer, you know that.

Junk is junk no matter how it is adjusted. Thee is more at work there than just co-planer.

Nothing wrong wit co-planer or any adjustments being as good as possible. There is a point where it just becomes too anal. I'm not knocking Duginske (I have his book) but I've also seen the work Phillips has done. Ed snipped-for-privacy@snet.net http://pages.cthome.net/edhome
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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
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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
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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
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On 5-Apr-2004, snipped-for-privacy@sewanee.edu (Hylourgos) wrote:

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
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That is indeed the case. Google honors the X-No-Archive header.
scott
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Yep, that was it. Now we both know.
H.
(Hylourgos) wrote:

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

We're not talking about a precision cutting machine here Mike. But, in any event, I'll try to sum it up with an analogy.
Being an engineer, I'm sure you know that older cars had points that required adjustment in order for the engines to run properly. I remember an old Mustang I worked on in high school - I could never get that thing running quite right. Did everything by the book - points were perfect, timing was perfect, vacuum advance was perfect, all according to the book.
When I asked the instructor what could be wrong, he said that sometimes you start with the factory settings and tune according to feel. Once I figured out what he meant, I adjusted the points and timing a bit and that Mustang purred.
Same thing for a bandsaw. The problem with most bandsaws is that you can't state a blanket "no more than 1/8" out of coplanar", because of manufacturing issues - cast or sheet metal frame, single or double wall construction, aluminum or cast wheels, rubber or urethane tires, size of crown, type of bearing, etc.
Most hobbyists don't really care about the fatigue on a band, as we don't use our tools in a production environment, and if they read all the books by Duginske, they already know to detension the band after use. I would say that most hobbyists are more concerned about performance, and in my case that is all I care about. My bandsaw is close to 50 years old - a sheet metal framed Delta 20" with new bearings, tires, even paint. No matter what band I use on her, she's a bit outta whack. I could shim and check, shim and check, shim and check. Or, I can leave well enough alone and cut wood.
I don't have a newer bandsaw to compare to, so I have no idea how much out of factory spec the new Deltas, Jets, or Lagunas might be.
Is Duginske wrong? Not necessarily. But is perfectly coplanar necessary for a well tuned 67 Mustang? I'll leave it to you to decide.
--
Regards,

Rick

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I think that unless the bandsaw is a real loser, the only significant issue is tire type and geometry.

That's entirely possible. However, I keep it in the realm of the possible that for some situations, fatigue _might_ reduce the life of the blade. Without doing some calcs, I don't know. However, the conservative engineer part of me says "do it right and don't even consider the possibility." Setting up a bandsaw is not hard, so don't make an issue of _not_ setting it up right.

I've already said that perfect is not possible, but "good enough" is. "Coplanar is a myth" doesn't even address good enough. Since making the bandsaw reasonably coplanar is straightforward, do it and if you're still having problems, you know to look elsewhere for a solution.
Mike
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snipped-for-privacy@magma.notthis.ca says...

If you mean geometry of the crown, I'd agree. The problem with geometry is dealing with a particular band or tensioning device/spring. A 1/8" band on my 20" Delta may require the upper wheel to be at a severe angle, thus negating or accentuating the OOC (out of coplanar) condition. OTOH, a 1" resaw blade requires so much tension that the wheel could be forced true.
In these cases, geometry is directly affected by the size, type, and material construction of the band - not to mention the weld/solder joint, which could open up another can of worms...

Agreed. But just what is *right*? There is clinical right, which is probably close to what you espouse. There is functional right, which is more of a gray area and works on the premise of feel instead of original spec. In reality, no one is wrong. I use the book as a starting point. If it works, I leave it. If it doesn't, I tune it according to common sense and feel. Am I "more right" than you? I don't really care, but my way works for me.

Agreed, but aren't you contradicting yourself a bit here? First thing I learned as a network engineer is that similar is spelled "different". Reasonably coplanar is not coplanar, therefore "coplanar is a myth" is technically correct. :-)
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Regards,

Rick

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