True coplaner bandsaw wheel adjustment?

[Chris Parks]

I concur with the myth and raise you one. True co planer simply can't be done, it might be done at rest with no band on it but as soon as the tracking is moved all that unneeded work went out the window because the top wheel was moved. The top wheel will move as soon as tension is put on the band because it is meant to move.

[John TenEyck]

My experience with my 14" Delta is very much the same as yours, Doug. With all due respect to Mr. Snodgrass, if a saw will not cut straight, no matter how many adjustments you make or how many new blades you try, then something must be wrong. I do not accept that you should adjust the fence on your bandsaw to account for drift; that's just stupid. If that were the correct response then we should adjust the table to follow that drift, too, and I've never heard anyone say that. If you can't adjust your saw so that it cuts straight and parallel with the miter slot then something is wrong and requires a deeper dive. For me, it was the wheels. I had to shim out the upper wheel at least 3/16". I also had to pivot the upper casting several degrees in order to get the wheels in plane on both sides of the axels. I also had to slide the upper casting a little left/right in order to get the blade perpendicular with the table when viewed from the front so that the guides would stay centered over their full range of travel. I took the table off of my saw which made checking wheel alignment very simple with a straight edge. You have to let the top wheel tilt as needed in order to get the straightedge to line up on the flats of the front of both wheels, but that's a simple adjustment.

When I was done the saw behaved completely differently. It was easy to get a blade to run centered on the top wheel, and it cut like a dream; straight and parallel with the miter slot with only a little adjustment required of the tilt mechanism. Of course when you adjust the tilt of the upper wheel the wheels are no longer exactly coplaner, but that's the way bandsaws run. And aligning the wheels is the only way I can see that will get the blade to run perpendicular to the table when viewed from the side. That may not be important for resawing but it sure is if you use your saw to cut joinery.

When all else fails, check the wheel alignment.

John

[Bill Space]

Chris,

With my saw, the wheels are set coplaner and the blade tracks close to the center of the wheels top and bottom. No need to tilt the top wheel. So it seems coplaner operation really is possible.

Of course, as Van has said, perhaps there are reasons one would want to tilt the top wheel. For example, tilting the top wheel out of coplaner may increase blade stability. Something I learned in this thread.

I think it might be fairer to say “The need for bandsaw wheels to be perfectly coplaner is a myth.” But “perfectly coplaner“ is a contradiction of terms.

My revised take on the issue now is... Close to coplaner is good enough! (And might even be better)

Bill

[Chris Parks]

No, the wheel must tilt to change the tracking. If you hold the wheel with no band on it the wheel can be moved back and forth.

A mention was made of moving the table, in fact this is a good idea if you have a saw that has persistent tracking problems, lock the fence and adjust the table so the blade can be put in the centre of the wheel no matter what the blade size. Every band change can then just about be done by eye or if not it won't be a long way off.

[Rod Sheridan]

I've been out on a few service calls where the owner of a new band saw complained that the wheels weren't coplanar, to which I replied "good".

I then go through the saw setup, put a blade on it, adjust the tension, tracking and guides, make a couple test cuts, measure the results and have the customer sign the work order.

Some still complain that the wheels aren't coplanar and they need to be because they read it on the internet. I explain how to adjust the tracking, show them the section in the manual that illustrates where on the upper wheel the blade is supposed to be and ask them what is wrong with the resaw test.

Band saws are one of the most mis-understood machines I've seen.........Rod.

[Chris Parks]

Ain't that the truth. Try and explain that some BS's have flat wheels and they tell you it can't be so.

[Steve Demuth]

I think most people, when they think "bandsaw wheels .... coplanar" are really saying that the two circles defined by the center of the wheel rims need to be coplanar. As many have pointed out here, they seldom will be, and shouldn't be, for best blade tracking. If you go through the effort to so align them, as soon as you change the upper wheel tracking, you'll have removed what you just laboriously created.

That said, the bottom wheel bearings are adjustable for a reason. You do need the twist of the wheels to be essentially zero. That is, if you draw a line between the two wheel centers, and then draw perpendiculars to that line through the center of the wheel rims, those latter two lines need to be in the same plane - otherwise you're trying to force the blade to twist. Once you've got that part right, you're going to want some small angle between the plane of the lower wheel and the plane of the upper wheel for all the reasons articulated by others in their posts. You mostly get that from the tracking adjustment on the top wheel, but if things have been really boogered up along the way, you many need to adjust the lower as well to get tracking within the range of the top wheel. This does not induce blade twist but rather adjusts how the plane formed by the blade relates to the two semicircles of wheel rim that it rides - its tracking.

If you want to think in lumber terms, imagine a board whose four corners are the the four lines formed by where the blade meets the two wheel rims as it rides onto and off the wheels. You want that board to have no twist, but a slight bow (it can't have cup, since the wheels are rigid in the cup dimension).

[Bill Space]

No, the wheel must tilt to change the tracking. If you hold the wheel with no band on it the wheel can be moved back and forth .

Chris, not sure what your “No” was referring to. Granted if one wants to change the tracking, tilting the upper wheel is necessary. But if tracking is where it should be after the wheels are set coplaner, there should be no need to change anything, unless I am missing something.

In the case of my D & W 20” bandsaw, the top wheel can be twisted back and forth even with a tensioned blade on it. When released the wheel returns to its equilibrium position. I understand this design is unique.

Bill

[Bill Space]

...I then go through the saw setup, put a blade on it, adjust the tension, tracking and guides, make a couple test cuts, measure the results and have the customer sign the work order...

Rob,

I take it that the set set up you go through before putting the blade on the bandsaw has nothing to do with the position of the wheels?

[Bill Space]

Expanding on what Steve has said, when setting the wheels coplaner two things are accomplished. The first is that the wheels are in the same plane, but only until the tilt of the top wheel is changed. Then the wheels are no longer coplaner, obviously.

But all effort made to make the wheels coplaner is not totally lost when the top wheel is tilted. The relationship of the wheel axles with respect to twist does not change with top wheel tilt. So setting the wheels coplaner to begin with is not a total waste of time as some may think. It is actually a measurable way to ensure that the wheel axles are orienrated property to produce no twist between the wheels.

Does wheel twist between the wheels matter? Can’t quantify it myself. Buy intellectually it seems to me that no twist would be better than having twist.

[Bill Space]

The two non-coplanar wheels produce an opposing force which prevents the tracking adjustment
When one moves the wheels into coplanar alignment they experience an increase in control and responsiveness of the tracking adjustment BUT what they have also done is reduce the saws ability to control the blade. It is like setting a cars camber and toe-in to zero simply because it is "logical" for a cars front wheels to be coplaner, trust me you don't want to try to drive that car at highway speeds.

Van,

I am am going to prove my ability to over think things.

It looks to me that the bandsaw is more like a motorcycle than a car. No camber or toe in on a motorcycle. Just caster, which I am not sure relates to the bandsaw.

So I am not sure your analogy has the strength it first appeared to have...

Wheel tilt does come into into play when making a turn however...

Another question popped into my mind. I take it that the Taiwanese design is a “parallel planer” design, in other words, if the two planes the wheels find themselves in were moved so they became one, the top wheel tilt could be adjusted to make the wheels truly coplaner.

Or to put it another way, they start with the wheels coplaner and shift one so that it resides in its own plane that is parallel with the other wheel.

Is this his assumption Correct?

[Rod Sheridan]

Rob,

I take it that the set set up you go through before putting the blade on the bandsaw has nothing to do with the position of the wheels?

I've never seen a saw that cannot track and cut properly when properly setup. The saw comes from the factory with some offset, as the saw works 100% in that condition, I've never had to correct that "deficiency". I assume that since the saws have some factory calibrated offset, they're designed to work that way.

Now, if the blade tracking was really wonky, for example at the back of the left of the wheel and at the front on the right of the wheel, then I would certainly correct that, however I would never check for coplanar, or adjust that if the spindles were in alignment. It's only if the spindles weren't in alignment that I would do something about it.

From a field service perspective I'm certainly not going to start taking a new machine apart to correct a non existent problem. I have had customers who were worried that the wheels weren't coplanar and the blade tracked in different spots on the upper and lower wheels. My response to them is always "If the saw stops cutting properly, please call me, here's my business card".

Haven't had a call back.

Likewise I get customers complaining that our saws don't have glued on tires, when I ask them why that's a problem they state that they learned that on the internet. Once again I ask them to contact me when it becomes a problem, never heard back from anyone on that issue.

I really think that these issues are non problems, or they are problems on really low end saws, ours start at several thousand dollars and maybe once you're at a certain price point you don't have those issues?

40 years in industry and I've never seen any of the serious "band saw issues" you read about, including de-tensioning the blade after use.

This what I find are the top 3 saw complaints.

Number one saw issue..............Wrong blade for the task

Number two saw issue..............Blade tension too low

Number three saw issue............Customer has used the blade for 3 years and the saw doesn't cut straight any more

For such a simple machine it sure causes consternation unlike any other shop machine.................Regards, Rod.

[Chris Parks]

I've never seen a saw that cannot track and cut properly when properly setup. The saw comes from the factory with some offset, as the saw works 100% in that condition, I've never had to correct that "deficiency". I assume that since the saws have some factory calibrated offset, they're designed to work that way.

Now, if the blade tracking was really wonky, for example at the back of the left of the wheel and at the front on the right of the wheel, then I would certainly correct that, however I would never check for coplanar, or adjust that if the spindles were in alignment. It's only if the spindles weren't in alignment that I would do something about it.

From a field service perspective I'm certainly not going to start taking a new machine apart to correct a non existent problem. I have had customers who were worried that the wheels weren't coplanar and the blade tracked in different spots on the upper and lower wheels. My response to them is always "If the saw stops cutting properly, please call me, here's my business card".

Haven't had a call back.

Likewise I get customers complaining that our saws don't have glued on tires, when I ask them why that's a problem they state that they learned that on the internet. Once again I ask them to contact me when it becomes a problem, never heard back from anyone on that issue.

I really think that these issues are non problems, or they are problems on really low end saws, ours start at several thousand dollars and maybe once you're at a certain price point you don't have those issues?

40 years in industry and I've never seen any of the serious "band saw issues" you read about, including de-tensioning the blade after use.

This what I find are the top 3 saw complaints.

Number one saw issue..............Wrong blade for the task

Number two saw issue..............Blade tension too low

Number three saw issue............Customer has used the blade for 3 years and the saw doesn't cut straight any more

For such a simple machine it sure causes consternation unlike any other shop machine.................Regards, Rod.

That about wraps it up neatly Rod, I have owned and have at the moment expensive European saws and cheap low end Asian saws and they all do what BS's should do with no issues. Without being critical of Bill the OP I think the internet is a myth building machine of the first order when it comes to stuff like this. People looking for advice on why the BS won't do what it is supposed to hear about drift and coplaner and through no fault of their own think these issues exist and need major work to fix them like moving wheels etc.

[John TenEyck]

The arguments related to not needing to check wheel alignment may be valid for new machines. I bought a new Grizzly bandsaw a couple of years ago and didn't bother checking them, and the saw cuts beautifully. For what it's worth, the blade is dead perpendicular to the table when viewed from the side, so I don't know how the wheels could be anything other than in the same plane with the blade under tension. Anyway, many older machines have been used, abused and worn, like my 50 year old 14" Delta must have been. In those cases, when nothing else works to get the blade to cut straight and parallel with the miter slot, you have to start looking for the root of the problem. Whether or not the factory set the wheels coplaner or not is irrelevant if the saw no longer cuts straight and you've tried all the things so often cited above. And if putting them coplaner is "wrong" but the saw now cuts straight, I'm fine with that.

John

[Rod Sheridan]

You are correct John, if the saw doesn't work, then you correct it.

What I don't do is correct issues that aren't supported by performance of the saw..........Rod.