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Setting the blade - what is acceptable difference between left and right side

Started by MobileSawMilSlo, May 14, 2019, 05:44:36 PM

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MobileSawMilSlo

Hi guys

I am a little bit confused about one topic.

When listening to Woodmizer, they say that setting tooth of the blade is extremely important and that the tooth should be set very precise.
Woodmizer even seels BMT300, which looks very good machine with even "push back" mechanism.

But on the other side ... I have listened to Cooks video when he said ... "yes, the setting is important, but not as much as people would think".

I am wondering ... what is the acceptable difference between left and right tooth?

For example, if we set to one side to 0.24 and other on 0.27 ... will blade work or would do waves? If let say 10 teeth from 179 are not exact precise ... will blade still work OK?

Because it is very hard to set all tooth to exact the same set with mechanical setter ... BMT300 is a totaly different story.

What do you think?
Woodmizer LT20 mobile and TTP-600 Premium Plus
DAJK - all sawing equipment in one place

terrifictimbersllc

You finished with a very insightful question. Responses might specify 1) what you think, or 2) what you know. 😎

By the way, where is this BMT 300 of which you speak?
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

MobileSawMilSlo

Quote from: terrifictimbersllc on May 14, 2019, 06:22:15 PM
You finished with a very insightful question. Responses might specify 1) what you think, or 2) what you know.

By the way, where is this BMT 300 of which you speak?
Ok, then what do you think :) :) :)
Here is BMT300 image:

Note from admin. Read rules on posting images. Links to offsite photos  not allowed 
Woodmizer LT20 mobile and TTP-600 Premium Plus
DAJK - all sawing equipment in one place

Chuck White

I set my blades with a Cooks single-tooth setter!

I have 2 marks on the dial indicator, 1 mark at 25 and the other at 30, and when the needle light anywhere in between the 2 marks the blade is good, invert the blade and do the other side, then sharpen.

When you think about it .005" or 5/1000" isn't very much.

With my blade set as indicated above, I usually saw between 750 and 1,000 board feet when sawing White Pine, Poplar, Hemlock and similar logs!
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

John Bartley

I have always set and sharpened my own bands.  I started learning about "set" after a difficult time at the start of my sawing when I knew nothing and had nothing but waves in my boards when sawing eastern white pine. (this was a decade ago)  I was using new blades, very sharp, but set at 0.021".   Nothing I did ... cutting speed, lube, band speed, nothing helped with the waves.   The guy I was sawing with asked about "set", so we did some reading and found that some cutters found relief from waves in knotty & pitchy wood by increasing the set.  I took mine out to 0.027" and instantly had straight boards.   In hardwoods, the 0.021" set cuts just fine.

My experience is that properly set bands will cut straight, even when dull.  Improperly set bands will wave, especially at knots, even when sharp.

So, in answer to the OP's question .... I would think that set is very important and I would also think that setting both sides equally would be necessary to get good cuts with less stress on the bands and mill.

... just my $0.05 ....
Kioti DK35HSE w/loader & forks
Champion 25hp band mill, 20' bed
Stihl MS361
Stihl 026

Bandmill Bandit

With carbides there is no setting to do but on my bimetals and double hards I set to 30 - 33 and have been for years now. Justs work better in every aspect of sawing I find.

If your set is different side to side you will get bobbing and weaving like a snake in the ocean creating  waves and swells in your lumber. 

The wider set does a few things;  
1) clears saw dust better  
2) creates enough space for more lube to stay on the blade in the cut
3) reduces blade operating temp by about 10 to 15% ( I've tested this with laser temp gun)
4) increases blade life about 20% to 25% 

Set isn't just sort of important it is critical in my less then humble opinion on this topic and the lumber I produce is the proof that NO one will ever dispute. 

EVERY band saw operator that sees my lumber asks how I can get such smooth straight cuts. 
With carbides it is the band quality itself. With all others I've used it is accuracy of AND width of set. I set mine to with in 3 thou +/- a thou and I do it on a manual setter. It is a bit slower to be that picky but it is worth it over all.

90% of ALL lumber quality issues are in the band and how you manage them.    
Skilled Master Sawyer. "Skilled labour don't come cheap. Cheap labour dont come skilled!
2018 F150 FX4, Husqvarna 340, 2 Logright 36 inch cant hooks and a bunch of stuff I built myself

dgdrls

I agree with @Bandmill Bandit
Set is critical and matching it on both sides saves you from poor cuts and frustration.

D



Pabene

I have some experiences about set. If you have all teeth set within 0.001" but one tooth has a set of 0.003" you will see scratches in the surface on about every Inch (depends on feed speed) from that tooth. If you have all teeth set within 0.003" in a random pattern you will see a more rough surface on your boards. I don't think it is so important to have the left and right side set absolutely equal. Years ago it was discussed here to roll the blades flat. If you run a blade some hours in your mill it is now longer flat. I do'nt know if there are any setter as can handle blades as are out of flat. I have a Cooks single and two better setters. I have to adjust the Zero each time I put in an other blade or flip a blade from right to left, exept if it is a new flat blade. Based on that I think most sawers are running blades with an unknown difference in set side to side. For me a difference side to side of 0.004" would'nt be a problem.

MobileSawMilSlo

I really appreciate all the answers you did.

Is set for 0.030" or even 0.033" too much for 23 HP Kubota engine?

I will check the difference between 0.0024 and 0.0033 on spruce and let you know how it will perform :)

Woodmizer LT20 mobile and TTP-600 Premium Plus
DAJK - all sawing equipment in one place

Bandmill Bandit

OK met me explain in a bit more detail;

My target set is 31° +/- 2° degree, hence the range of 29° to 33° max! NO MORE or LESS. Side to side set MUST be equal (with in the range) ! If you over set use the little tool that came with the setter to correct the over set and REDO that tooth to EXACT tolerance range.

Tolerance side to side is ZERO°! set them the same. I stay with in a +/-2° thou range!

BOTH sides MUST be within the same tolerance range. 3° thou +/- off target isnt gona show on the lumber. You have to be 5° thou or more to start showing the "tooth ridge"! I have measured bands that were doing that and 5° thou is enough to start showing them.

Mobile saw; more set equals over all less blade friction with a very minor increase in biting edge resitance of the tooth. The extra set is not an issue for you.

Any one who will tell you that blade sharpening and setting is NOT critical has NOT sawn enough timber for best quality and high productivity to know what they are talking about! With 12 years of sawing well over million board feet under my belt I think I might know a bit about doing it RIGHT and how important it really is .          
Skilled Master Sawyer. "Skilled labour don't come cheap. Cheap labour dont come skilled!
2018 F150 FX4, Husqvarna 340, 2 Logright 36 inch cant hooks and a bunch of stuff I built myself

YellowHammer

All cutting is being done by the teeth, and therefore the better the shape and sharpness of the teeth, the better the cutting.

So with that being said, when I was trying to figure out the acceptable tolerances and deviations of the various makes and styles of bands (I tried quite a few, but not all) I would simply put a few of the new ones in the setter, back the anvils off, and start measuring them.  That would tell me what the manufacturer is really doing, as opposed to advertising.  From that I would learn the basic set distances of each type, the manufacturer deviations, range, etc.  Then I would saw with them, and see how they worked out.  It was a very useful and educational experience and taught me a lot about what matters.  If nothing else, it would tell me what the manufacturer's set is, and what I should do, at a minimum.

Also, as I'm sure you've had the experience too, every once in a while I would get a "magic" band out of the box, one that just performs head and shoulders above others, even though they were all supposed to be the same.  That band would always go on the setter where I could measure exactly what made it so good.  Then I would take that knowledge and try duplicate it.    

By doing this, your bands will be at least as good as out of the box bands, and by paying attention to those details, its not hard to sharpen and set bands that cut noticeably better than new.  



YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Pabene

I am sorry my English is so bad, I just want to say what I have seen and I hope it can be to help for someone.
How do you know the real set, if the blade is concave on one side, convex on the other side and the setter does'nt has force enough in its holding yaws, to press it flat? The next question is how do you know the blades "attitude" in the mill, when it rides with the convex side against cylindric guide rollers? When it comes to read the correct or best set you have to know about this. An other thing is how the teeth are bent out in the setter. I have seen when the setter has pressed the tooth close to its back. That means you will have a negative relief angle on its side but still will read a good value on the dialindikator.

YellowHammer

I measure the set in my dual tooth setter, the same way as I measure the set when setting the teeth normally.  I simply back the anvils out a little to not contact the teeth, therefore not disturbing the set as I want to measure it, but the clamping jaws which is not affected by backing out the anvils, still clamps the band firmly and tightly and holds it flat.  So the dial indicators and the set is measure on a firmly held and flat band.

My indicators are adjusted to contact only the outside tip of the tooth, so it measure true set.

My setter has been modified so that the setting anvils press against the inside tooth tip, and the indicators measure from the outside, so even if there is any twist, curl, or anything, only the true set of the tooth tip is measured.

 
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Pabene

I agree with Yellowhammer. I don't know about his dubble setter, it is maybe better tha what I have seen. Here is a try to better explain the problem you may have if you want to measure the set better than 0.001". My scetch shows three cases of cross sections of a used blade in a single tooth setter. In the first one the blade is hold firmly and the set results depends a little of the holding force. If the holding force is equal and even from stroke to stroke it is OK. The seccond scetch shows when the blade is flipped and the convex side of the blade is pressed against the flat surface on the fixed jaw. Here it doesn't matter how hard you press the holding yaw, it still remains a play in the point you will bend the tooth. You can also see that play will give you a false reading of the set. In the scetch three I have tried to show a solution how to modify a setter to make it better. (I have not fullfilled that mod completely by my self yet).
If someone would belive the blades stays flat when it runs in your saw it is documentations about it, look for "Anticlastic curvature".
 


 

kelLOGg

Pabene,

Very interesting analysis. I have assumed that a band with curvature is temporarily flattened during the setting process because the CatClaw setter actuating handle has an adjustable throw that "snaps" when the maximum throw position is reached giving the same high pressing force every time. During sawing with a band with curvature the effective set probably changes. I think this is why Cooks swears by band rolling to make sure the band is flat. However, I don't roll mine.

An interesting test for curvature is to put the band in the setter and back off on the anvil so it doesn't contact the tooth and then actuate the handle. If the dial indicator moves there is curvature. Does anyone have a suggestion for an easy way to check for curvature for a blade mounted on a mill? I have found that looking for a crack of light between the blade and a straightedge is difficult when installed on the mill.

I'd welcome feedback because my observations may be out to lunch.
Bob
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

John Bartley

I know Pebene's theory is solid, no question.   The question I have is ... how much curvature is there in a band that is 1-1/4" from back to blade tip?   I guess what I am asking is ... is it significant enough to warrant caring about, or is it one of those things that only a truly anal sharpener would spend time trying to solve?  This is not meant to offend Pebene, as it is people like him who question the "normal" who tend to be our problem solvers.  I ask because after almost 12 years of sharpening and setting my own bands and running a mill that I bought new, I've never had a band do anything other than cut straight when properly set and cut fast when properly sharpened and although I've heard about and read about "rolling" bands to be flat, I've never done it.

?
Kioti DK35HSE w/loader & forks
Champion 25hp band mill, 20' bed
Stihl MS361
Stihl 026

barbender

I think it was @Percy that said he increases set on one side of his blades to offset any curvature, since he doesn't have a band roller.
Too many irons in the fire

John Bartley

Just for the heck of it I went out to the garage and measured ....  I have a couple of bands here that have been with me for many years (11 I think) and have probably been sharpened at least ten or fifteen times.   I never run my bands past about four to six hundred board feet before I clean, set and sharpen (in that order).  I do all my own sawing, cleaning, setting and sharpening, and being a hobby sawyer I likely only have about 5000 bd ft on each of these bands.  I put a straight edge across the bands .... can't get a feeler gauge in there ... can't even see daylight.  I would have to say that my bands have no curvature across them.  My bands run on belts.  Maybe that's why.
Kioti DK35HSE w/loader & forks
Champion 25hp band mill, 20' bed
Stihl MS361
Stihl 026

Bandmill Bandit

I just checked one of each; double hard, bimetal, carbide. 

Just like John I can't even get a glimmer light under a steal mechanics ruler. 

I'd say it is not an issue. At least not with Woodmizer bands!
 
Skilled Master Sawyer. "Skilled labour don't come cheap. Cheap labour dont come skilled!
2018 F150 FX4, Husqvarna 340, 2 Logright 36 inch cant hooks and a bunch of stuff I built myself

Woodpecker52

Woodmizer LT-15, Ross Pony #1 planner, Ford 2600 tractor, Stihl chainsaws, Kubota rtv900 Kubota L3830F tractor

Pabene

The question in the #1 post was: What is an acceptable difference in set between left and right side of the blade? For me, I stated in post #7, 0.004" would not be a problem. Then I just tried to explain why it is hard to make a correct measurment of the set on one side like the scetch #2, from May 17. For much more experianced people than me and with other equipment it maybe can be possible. I have not rolled blade my self but I am looking at the flatness so I know where I am in my procedure. About anticlastic curvature, it is a law of nature and I dont think it is possible to avoide such impact. I am satified with the results I have from my saw mill, stright cut and smoth finish.

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