Bandsaw drift and adjusting for it.

[Bill Huber]

I viewed a video from another post and did not want to hijack that one so I started this one.

I am not an export on bandsaws but I do know what works for me. People talk about setting the fence for the drift all the time but they don't talk about getting the blade to cut straight to start with. I understand on a flat wheel saw you have to set the drift to the blade but on a crowed wheel I can't see it and I think most of the small saws have crowed wheels.

I put a blade on my 14" Jet and track it to the center as close as I can, then I check the cut. If it is cutting in I adjust the blade a little back on the wheel, if it cutting out I just it more to the front. If I can not get it by doing that I must have a bad blade

I never have to change my fence and I can cut a 1/8" strip off a board with no problem.

So is my bandsaw just unique saw or what.

[Mark Ashmeade]

I used to have a 14" Ridgid, and it would drift significantly.

I found that blade tension was critical, and basically the drift angle was directly proportional to the blade tension. problem was, with a small diameter tension wheel, it was difficult to ratchet up the tension enough to reduce the drift.

I eventually upgraded to a 17" steel framed saw, and it does not have *ANY* blade drift. Set the fence, saw, done.

I was all ready to put a tension crank on the Ridgid and various other upgrades, but I had a cathartic moment, and realized I was actually pretty close to the cost of the Grizzly G0513P with the extra investment.

[Bill Huber]

I used to have a 14" Ridgid, and it would drift significantly.

I found that blade tension was critical, and basically the drift angle was directly proportional to the blade tension. problem was, with a small diameter tension wheel, it was difficult to ratchet up the tension enough to reduce the drift.

I eventually upgraded to a 17" steel framed saw, and it does not have *ANY* blade drift. Set the fence, saw, done.

I was all ready to put a tension crank on the Ridgid and various other upgrades, but I had a cathartic moment, and realized I was actually pretty close to the cost of the Grizzly G0513P with the extra investment.

When you install the blade do you track it to the center?

So what I am thinking is that all the problems with drift on a crowed wheel could be eliminated with a good saw set up.

[Mark Ashmeade]

On the Grizzly? Yes. It tracks very easily.

On the Ridgid? Yes, but its natural sweet spot was just off the crown. It would track reliably a little toward the back of the crown. All kinds of alignment, vibration and tension issues, but by the time I resolved most of them, I realized it was time to move on.

[Dan Karachio]

Bill, you are my hero. I think about this and practice it too. My saw, a Rikon 14", cuts straight as an arrow and I have never touched the fence. I do exactly what you describe and it works. I resawed a half dozen 1/4 panels the other day and ripped some rough stock. Perfecto. It's about tracking, not fences. I'm guessing that having a good set of coplanar wheels might be a requirement, but maybe not.

[Van Huskey]

So is my bandsaw just unique saw or what.

Blades drift not saws so your saw is not unique. You can adjust out drift with top wheel adjustment SOMETIMES. Depending on your fence it is sometimes easier to adjust with the wheel tracking, with something like the Driftmaster fence it is easier with the fence. Plus depending on the cuts you make you may or may not even notice subtle drift.

Narrow blades
Dull blades
Blades with damaged teeth set
poor quality blades
too low tension
to dense TPI

All of these can cause drift along with the wrong blade for the task or material.

[Bruce Wrenn]

Bill's method only works on saws with crowned tires, which includes most 14" saws. But a blade with teeth set unevenly to one side, or dulled on one side won't be corrected using the crown of the tire.

[Russell Smallwood]

I suppose changing the angle of the blade is the same thing as changing the angle of the fence :)

I used to do a lot of single-handed sailing and when I was up on deck working on the sails/mast I would lock the tiller and steer the boat by grabbing the mast, leaning over the side and changing its heel angle. Same results, same physics just a different approach.

Interesting tip Bill. I believe that Van is correct though in that the drift on a band saw is determined by imperfections in the blade teeth.

At least that's my understanding.

[Ken Fitzgerald]

Bill,

There are a multitude of things that can effect bandsaw blade drift and what to do to correct it.

I an tell you this.

I adjusted my fence for drift one times so far. I 've changed blades a couple of times and haven't had to adjust for drift but.....if I nick a nail with the blade.....don't get it tenioned properly....I might have to adjust it.

[Curt Harms]

Bill, you are my hero. I think about this and practice it too. My saw, a Rikon 14", cuts straight as an arrow and I have never touched the fence. I do exactly what you describe and it works. I resawed a half dozen 1/4 panels the other day and ripped some rough stock. Perfecto. It's about tracking, not fences. I'm guessing that having a good set of coplanar wheels might be a requirement, but maybe not.

Center the blade, adjust the guides if necessary and go. What helped me with resawing is to run a feather board against the table to keep the bottom of the stock against the fence. I had one Timberwolf blade go wacky, first it resawed fine then it didn't. Put a different blade on and life was good again.

[Bill Huber]

I know there are more then one way to do things, I work with computers all day but I guess my point is why don't people talk about it.

You can find bunches of videos on the net about how to set the drift and all but one of them that I have seen do it by setting the fence.

I think one of the other problems is that people push the wood to hard and do not give the blade time to work.

[Russell Smallwood]

I know there are more then one way to do things, I work with computers all day but I guess my point is why don't people talk about it.

You can find bunches of videos on the net about how to set the drift and all but one of them that I have seen do it by setting the fence.

I think one of the other problems is that people push the wood to hard and do not give the blade time to work.

+1 on feed rate affecting drift. I've experienced this myself. That's one of the things I love about the band saw, it can be as temperamental as a Stanley #55 one minute, then as sweet as well-tuned antique #3 the next.

[Chris Parks]

I know there are more then one way to do things, I work with computers all day but I guess my point is why don't people talk about it.

I bought a new saw some years ago and found it strange to find people talking of setting the drift angle when mine had no drift at all. I then looked at the guide system of the older and even most modern ones and they are mechanically stupid and must contribute to the drift problem. Whoever it was who thought it to be a good idea to use the back (thrust) bearing with the blade running across the face and not on the outside of the race must have been having a bad day. To compound it everyone obediently followed until recent times when Jet and a few others have turned the bearing around. Yes, I also never got the whole drift thing if the saw was set up right and a good blade was in it and having seen what is written here it is the same as I do, centre the blade as closely as possible, it just seems to be the common sense thing to do.

[John Coloccia]

My guess is it's to keep from wearing a groove from riding a blade in the same spot all the time. I don't know, though. It's just a guess.

[Van Huskey]

I think we should also consider that there are two significantly different levels of drift or lead. One is where the saw is setup incorrectly, blade is dull or teeth are damaged/malformed, low tension or the saw is being over fed. These will result in a blade that "runs wild' moving visually well off "straight". The second is drift that is measured in hundreths of an inch rarely visible making a cut but can be visualized when viewing the blade in a test cut (for setting drift) or measured when slicing thin veneer. The latter is what I an I assume most people use fence adjustments for when the quality of the desired cut warrants it, the former is what you have to fix via adjustment of the saw (or replacing the offending blade) because it will vary within the cut and not basically constant like the former type of drift. In my experience the latter is there 90+% of the time whether one notices it or not. I have seen it on all my saws and given the ones I have or had include an old PM 81, Laguna LT-18 and Minimax MM20 so not exactly bottom feeders and I was/am using correctly welded Lenox and Laguna blades.


So in response to Bill's initial question I think the discussion of setting drift usually centers around the very small drift I mentioned versus the larger drift caused by setup/blade issues, the larger drift I assume most people feel is part of setup and thus a different topic all together.

[glenn bradley]

So is my bandsaw just unique saw or what.

Nope. I'm from the "why adjust for drift when you can adjust the blade" crowd as well. I never change my fence and swap regularly from 3/4", 3/8" and 1/4" blades on my larger bandsaw.

Obviously, drift is an accepted reality; ergo the DriftMaster fence and others. I've had three bandsaws over the last 5 years and just adjusted them all to track "straight". They seem to stay that way regardless of blade changes. Either we're both doing something wrong or drift is waiting down the line somewhere to say "I told you so" :D:D:D

I all fairness, 1/16" is about as thin as I ever cut so there is probably a generous dose of what some folks consider drift present. It is just outside my tolerances due to the type of work I do and what I use a bandsaw for. Someone needing 3/64" veneer plus or minus tiny amounts may consider my saw horrible :confused:. I run 1/6" to 1/8" veneers to glue to substrates and clean up the saw marks with a scraper and am OK with it. Different needs for different projects :).

[Chris Parks]

So in response to Bill's initial question I think the discussion of setting drift usually centers around the very small drift I mentioned versus the larger drift caused by setup/blade issues, the larger drift I assume most people feel is part of setup and thus a different topic all together.

I would still back the guide/bearing design as an issue. The blade firstly contacts the top of the bearing face and tries to turn the bearing one way, it then runs past the opposite side of the same face and tries to stop it turning, or something of that nature. All this is applied to the back of the blade and there is no way that it can have zero effect on the blade, that is it must deflect the blade to some degree. By using the race outer face of the bearing in the manner the bearing was meant to be used the bearing applies no deflection at all thus can have no effect on the drift angle. I hope I have explained this adequately.

[John Coloccia]

I would still back the guide/bearing design as an issue. The blade firstly contacts the top of the bearing face and tries to turn the bearing one way, it then runs past the opposite side of the same face and tries to stop it turning, or something of that nature. All this is applied to the back of the blade and there is no way that it can have zero effect on the blade, that is it must deflect the blade to some degree. By using the race outer face of the bearing in the manner the bearing was meant to be used the bearing applies no deflection at all thus can have no effect on the drift angle. I hope I have explained this adequately.

The blade is offset. Both the top and bottom contact points are trying to push the race down, which will want to turn the bearing counterclockwise. If you draw your triangles you'll find the race is moving "down" the exact same amount at both points. There's no fighting going on at all. In fact, there's no way you could arrange it to get them to fight each other with a straight blade. Again, I suspect it's done like this to keep from wearing a grove down the bearing. You also get more contact area.

[Chris Parks]

If there is no fighting then why does the bearing not move in a continuous motion. I have never seen one move in a fluid continuous manner and to use it in this manner is not how the bearing was designed to be used.

[Bill Huber]

If there is no fighting then why does the bearing not move in a continuous motion. I have never seen one move in a fluid continuous manner and to use it in this manner is not how the bearing was designed to be used.

Wouldn't that be because the blade does not touch the bearing when you set it up and the only time is should is when you are cutting so hard that it pushes the blade back against it?

I have a gap between them and when the saw is not cutting the bearing is not even turning, when I start to cut an push the wood in it and it is having a little problem cutting then it will go back an it the bearing. If I keep the pressure on it it will turn just fine and smooth but if I slow the feed down some it will stop turning.

Don't know this for a fact but just thinking about it.

[John Coloccia]

There is a little bit of extra friction because there's a sideways component to the movement....to the left on top of the blade and to the right on the bottom for a blade mounted left of center. It's pretty insignificant, though. You can feel it just by pushing the blade into the bearing by hand and moving up and down. There's just really not much there for friction at all.

[Paul Murphy]

Bill, I have read an article in FWW by Michael Fortune (#173) where he says much the same thing.

A bunch of factors can make this approach difficult on some saws, and some of them don't have a lot to do with each other. Mark Duginske mentions that the manufacturing process gives bandsaw blades a different diameter at the front of the blade than the diameter at the back of the blade. That would likely cause drift for an otherwise perfectly centered blade.

One thing that makes zeroing drift difficult on some saws is that the guidepost/guide cannot easily be rotated. You can zero the drift without the guides, but then engaging the guides induces the drift already built into that assembly. If you have metal guides you can file them all to compensate, but filing 4 guides paralell to the table is more work than adjusting one fence. You could rotate the table, but often drilling all the holes to allow for adjustment involves a lot of work.

I agree that zeroing drift is worth trying, but in some cases it is not so easy to achieve. In the end if the saw can produce quality work then I'm happy even if it means the fence and blade are not "centered".

It is nice that you mention it, there is more to these machines than is in the manual that comes with them. :D