Bandsaw: tracking and drift and the snodgrass method

[Thomas L. Miller]

Adrian,
I squared the table on my 14" Grizzly by pulling all the blade guides back, tensioning the blade and running the blade while tracking the gullet of the blade to the middle of the top wheel as Alex Snodgrass recommends. Then, I put a 24" steel straight edge flush up next to the blade in between teeth. The blade I was using was a 1/2" wood slicer. I then (using magnifying glasses) measured the distances at each end of the miter slot and the straight edge. I had to move the table a tiny amount to take care of a huge amount of what I thought of as drift. Once this procedure was completed and the table repositioned to be absolutely parallel to the blade path, there is NO drift. The fence is set parallel to the miter slot and things are really great. My table got out of alignment when the saw was moved by holding the table rather than grabbing something like the motor or frame of the saw. If this explanation doesn't make sense, let me know and I'll try again.
Regards,
Tom

[Adrian Mariano]

Hi Adrian, the miter gauge slot should be parallel to the blade path.

Adjust your blade so it tracks properly on the upper wheel then make sure your miter slot is parallel. The table shouldn't need or be able to be adjusted much to do this.

Normally, tracking adjustments are miniscule, and I don't normally adjust it when changing blades.

I suggest you buy a good quality non carbide blade, and set up your saw.

If you're using a very small blade then you just look at the drift of the cut, drifting into the fence, blade too far forward. Drifting away from the fence, blade too far rearward.

As I said you don't normally adjust tracking once the saw is set up............Rod.

So what do you mean when you say the blade "tracks properly on the upper wheel"? At the moment the tracking on the wheel looks great. It appears stable and centered. But apparently it's not right..... And what should the miter slot be parallel to?

Are you saying I should get a non-carbide blade and use it to set up the saw and then switch back to the carbide blade? I'm a little confused about this. I had heard that, if anything, the carbide blades should be more reliable, because they are precision machined carbide teeth the set should be very uniform, so the blade shouldn't be the source of trouble (unless it's got something to do with the weld).

[Adrian Mariano]

Adrian,
I squared the table on my 14" Grizzly by pulling all the blade guides back, tensioning the blade and running the blade while tracking the gullet of the blade to the middle of the top wheel as Alex Snodgrass recommends. Then, I put a 24" steel straight edge flush up next to the blade in between teeth. The blade I was using was a 1/2" wood slicer. I then (using magnifying glasses) measured the distances at each end of the miter slot and the straight edge. I had to move the table a tiny amount to take care of a huge amount of what I thought of as drift. Once this procedure was completed and the table repositioned to be absolutely parallel to the blade path, there is NO drift. The fence is set parallel to the miter slot and things are really great. My table got out of alignment when the saw was moved by holding the table rather than grabbing something like the motor or frame of the saw. If this explanation doesn't make sense, let me know and I'll try again.
Regards,
Tom

Well, in this case you don't know that you got your table oriented with the miter slot perpendicular to the plane of the wheels, which is presumably what you would need for there to be no drift. Turning the table is one method of correcting for drift---it doesn't mean you don't have drift.

When I tried to estimate drift using the straight edge on the blade I didn't find the method to be reliable. I think I would need a wider blade for this to work. I used the test cut method to assess drift. This process works, and with the laser line level it's definitely not so hard to do a decent job of it, because it gives a mark in space to line the table up to as you adjust. But it's not clear that aligning the table this way aligns it according to the "blade path" that Rod has been talking about. I don't know what the difference is between the "blade path" and the cut line. Presumably this process lines up with the cut line.

[John TenEyck]

You will get straight cuts when three things happen: the wheels are coplaner, you have a sharp blade with equal set on both sides, and the blade is tracking properly (whether it ends up centered or not is irrelevant). If you are sure your blade is not the problem and you have adjusted the tracking without success, then I suggest you pull off the table and wheel covers and check to see if the wheels are in plane. My saw would not cut straight until I shimmed them planer. With all due respect to Mr. Snodgrass, who says not to bother checking them, it is critical they be aligned properly.

John

[Doug Ladendorf]

Adjust the tracking of the blade on the top wheel, until you eliminate the problem.

This ^^^ I did set up my 14" saw (PM 141) using Snodgrass' method and it worked great. With wider blades it might not work well as evidenced by other threads here on the subject. I have found that tracking on the wheel should be adjusted rather than changing the fence, have a good sharp blade, and the wheels do not necessarily need to be coplanar. On most saws when you adjust the tracking it's affecting the coplanarity, and you can knock yourself out trying to achieve both coplanar wheels and a properly tracking blade. If the blade is cutting wood straight then it's irrelevant whether the wheels are coplanar.

[Rod Sheridan]

So what do you mean when you say the blade "tracks properly on the upper wheel"? At the moment the tracking on the wheel looks great. It appears stable and centered. But apparently it's not right..... And what should the miter slot be parallel to?

Are you saying I should get a non-carbide blade and use it to set up the saw and then switch back to the carbide blade? I'm a little confused about this. I had heard that, if anything, the carbide blades should be more reliable, because they are precision machined carbide teeth the set should be very uniform, so the blade shouldn't be the source of trouble (unless it's got something to do with the weld).

When you have problems with a band saw, the first thing you do is change the blade for a different one.

I would start there.

Another issue with carbide blades is tension, many saws won't be able to tension them properly.

So with your carbide blade centered on the wheel, how does the cut look using the fence, toe in, parallel or toe out?

Regards, Rod.

[Erik Loza]

There are alot more bandsaws out there that cannot tension a carbide blade properly than can. Start with a fresh, simple blade and work out from there. Good luck,

Erik

[Kent A Bathurst]

If the blade is ......... dull it will not track properly when cutting.

I vote for dull.

I would suggest you mount a new resaw blade, and rule the blade in or out as the culprit, before you get too much deeper in saw adjustments...........

[Adrian Mariano]

When you have problems with a band saw, the first thing you do is change the blade for a different one.

I would start there.

Another issue with carbide blades is tension, many saws won't be able to tension them properly.

So with your carbide blade centered on the wheel, how does the cut look using the fence, toe in, parallel or toe out?

Regards, Rod.

My blade is tensioned to 15k psi according to my blade tension gauge, which is supposed to be adequate. I could increase tension. (It's not maxed out.)

Before I rotated the table the cut was towards the fence. Note, however, that the position of the table at this point was no magical thing. We took the table off to lighten the saw when moving it into the shop, so the table was not in any calibrated "correct" position, though it was roughly centered in its rotational range, I think. I rotated the table counterclockwise to try to line up the cut line with the fence.

Regarding coplanar alignment, I know my old saw adjusted tracking by tilting the top wheel, so if you want to be coplanar it forces you to set the tracking to a fixed, specific position to line up the top wheel with the bottom wheel. I did this on my old saw and I still had drift. And the tracking was kind of tricky with it set up this way. I once pushed the blade off the wheel (because the guide post wasn't parallel to the blade so if you moved the guide post without backing off the thrust bearing it would move the blade) and it took me half an hour to get the blade back on and tracking again. This doesn't inspire me to think that coplanar tracking is the solution to every problem. (And this saw & blade had drift.)

[Adrian Mariano]

I vote for dull.

I would suggest you mount a new resaw blade, and rule the blade in or out as the culprit, before you get too much deeper in saw adjustments...........

Why would a brand new blade be dull? If I have to worry about that possibility it seems like I can't hope to get anything working.

[Kent A Bathurst]

Why would a brand new blade be dull? If I have to worry about that possibility it seems like I can't hope to get anything working.

Did not read where it is a new blade - must have missed that bit. Sorry.

Even with a Trimaster, things can sometimes go wrong - but that is one damn fine blade - had 2, now 1, myself.

Still and all - if some teeth happened to get out of alignment somehow, somewhere, you could see tracking problems.

Just saying - for $20 or $25, you could toss on a wood slicer, or an olsen, and see what's what. Your frustration is coming thru loud and clear, and I don't blame you one bit - I would be righteously annoyed also. But - the scientific approach to solving problems is to eliminate possible variables from the list............

Don't give up.....if I can get my 14" delta c-Frame to resaw 10" WO, then it clearly ain't rocket science, because I am simply not that good.

You probably don't want to hear anything like this, but I will offer it anyway: There are many sources for info out there - a few have been mentioned here. The problem is, anyone with a keyboard and a smart phone can post videos that make them look brilliant. Or just a keyboard - and you get rocket scientists like Kent and Myk weighing in .........

To my knowledge, no one is better than Mark Duginske. Book is cheap on Amazon. Walk away from it for a day or two while the book is coming, take a deep breath, and walk through Mark's instructions step-by step - go back to the beginning, and challenge your assumptions.

FWIW - When I had my Trimaster, I put it on when I needed exceptional performance for resawing serious hardwoods, stuff like that - otherwise I had one of those other two on. Did not want to use that beauty on junk that got slapped through there to make jigs, hidden structural parts, etc. But - your case may well be different.....just sayin.

Keep us up to date - we feel your pain..............

[Allan Speers]

I tried the Snodgrass method once on my 14" Delta X5. When I adjusted to the point that a 5/8" blade's gullets were at the center of the top wheel, the blade moved so far forward on the lower wheel, it was scraping against the front flange!

I shook my head, then immediately put it back to where it had been working just fine, thank you very much.

This really puzzled me at the time. Should I have shimmed my bottom wheel out almost 1/2" just to use his method? Could my USA-made Delta have been THAT off from the factory? I don't see how.

Could I have been missing something else?

[Bob Wingard]

I tried the Snodgrass method once on my 14" Delta X5. When I adjusted to the point that a 5/8" blade's gullets were at the center of the top wheel, the blade moved so far forward on the lower wheel, it was scraping against the front flange!

I shook my head, then immediately put it back to where it had been working just fine, thank you very much.

This really puzzled me at the time. Should I have shimmed my bottom wheel out almost 1/2" just to use his method? Could my USA-made Delta have been THAT off from the factory? I don't see how.





Could I have been missing something else?

Do you have any shims behind the top wheel ??? Many folks put shims & washers there in an attempt to attain the coplanar state. I tried Alex's method ... had terrible results ... THEN ... I remembered I had put a precision ground shim behind the wheel trying for that coplanar status. I took it out ... readjusted everything and it works just as he professes. COPLANARITY is a MYTH !!! It is impossible to maintain coplanarity between two wheels where one must be adjusted for the purpose of tracking ... as soon as you adjust tension or use your blade tracking feature ... it is gone.

[Phil Thien]

Do you have any shims behind the top wheel ??? Many folks put shims & washers there in an attempt to attain the coplanar state. I tried Alex's method ... had terrible results ... THEN ... I remembered I had put a precision ground shim behind the wheel trying for that coplanar status. I took it out ... readjusted everything and it works just as he professes. COPLANARITY is a MYTH !!! It is impossible to maintain coplanarity between two wheels where one must be adjusted for the purpose of tracking ... as soon as you adjust tension or use your blade tracking feature ... it is gone.

You understand the logical consequence of your statement would be either:

(1) There is some ideal other than coplanar and saw wheels must be thusly aligned.

-or-

(2) Bandsaws work great provided the wheels are NOT coplanar.


#1 is unlikely, otherwise the relationship between the two wheels would have been published by a manufacturer somewhere along the line.

#2 is unlikely, as so many people have found that their saws work better as the wheels approximate a coplanar relationship.

So based on this, it seems likely that at some point you added the shim and actually moved your wheels out of alignment. Removing the shim brought them back.

Coplanar was a poor choice of words to explain that wheels should be aligned to induce the least amount of twist to a blade revolving around them. There is, of course, a point of diminishing returns here. But twist = vibration, and the more closely aligned the wheels, the less twist.

[lowell holmes]

I've used Duginske's book as a guide on my 14" Jet bandsaw. However, I added Carter after market guides to the saw. I stuck with Duginske's set up.

After seeing the Snodgrass video, I set my saw up in accordance to his suggestions. I feel like the saw is performing better after the changes, but the improvement is not great.
The saw seems to be running more free now and the blade tracks well.

I would be happy with either set up, but will not go back to the old set-up unless something develops.