I have heard and read in multiple sources that the top and bottom wheel on a band saw need to be aligned and in the same plane.
I had a discussion with my father who is not a wood worker, but a mechanical engineer, and his thought was that it really doesn't matter because the top and bottom wheels have an angle up to the center of the wheel. This forces the blade to move it's tracking location on the wheel from the lower edge up to wards the middle. And any difference between the two wheels is corrected in this angle shape on the wheel.
Can someone tell me why having the wheels in line with each other is important. Or direct me two a book that might explain it?
I have recently picked up a Jet Band saw, and the wheels are not in alignment by any means. I read in FWW#193 a review of the Jet and there complaint was that getting the wheels into alignment was not possible as the bearing shaft is just too short.
I'd like to understand what the reason behind bringing the two wheels into alignment is required for, before disassembling the whole unit to fix it.
Matt, I cut and pasted this artical. It is from free info.
It really makes a big difference making the wheels coplaner as the machine does not fight and use the guides to compansate and work extra hard from poor alienment. But you may want to get the machine running, order some spacers and work on it a little later. You may want to upgrade some of the other parts on the machine. I am sure R&D Bandsaw can supply the parts.
Good Luck, Mark
In your catalog you've said more than once that "making the wheels coplanar" on a bandsaw is an important part of tune-up, but as far as I know you haven't described how to do it. I have just a few questions: what is it, how do I know if I need it, and if so how do I do it?
Hmm. Seems we've left a few details yet to cover, eh? The object of the exercise is to make your two bandsaw wheels lie in the same plane while you're cutting wood. When your wheels are coplanar, blades tend to track stably, and perhaps best of all there's little or no adjustment required when you change blades. It's much more likely that your blade will be perpendicular to the saw table, and your upper guides are less likely to require adjustment when you change depth of cut significantly.
Are your saw's wheels out of plane? A snap diagnosis might be easy: if you have to fiddle with the saw's tracking knob every time you change blades, you are going to benefit distinctly from making the wheels coplanar.If you're not sure, here's another quick check: if there's a blade on your saw now, go look at it. Is it in the same position on the upper wheel as on the lower? If you can see a difference without measuring, then your wheels are almost certainly running in different planes.
Put a 1/2" blade on your saw and tension it as if for work. Don't bother tracking it; you're just going to take it off again in a minute. Lay a 4 ft. straightedge against the lower wheel, as close to the center as possible. With the straightedge touching the wheel's rim at both top and bottom, check the upper wheel. Use the tracking knob as needed to make the rim parallel to the straightedge. If the upper wheel doesn't touch the straightedge, or if it pushes the straightedge out of contact with the lower wheel, then adjustment is called for.
On Delta and Jet bandsaws, the upper wheel can be moved outward by dismounting it and installing a 5/8" i.d. spacer on the shaft. A hardware store 5/8" washer will work if you need to move the wheel at least 1/16". Some hardware stores stock machine bushings, narrow-rim washers available in a variety of useful thicknesses. Be sure the bushing already on the shaft is reinstalled last, just before the wheel. On Sears 12" and Inca 10" saws, the lower wheel can be moved by unlocking a set screw and shifting the wheel on its shaft. For other saws, have a good squint and figure out which wheel is adjustable.
It's easy to set the wheels coplanar, and the payback is mighty convincing. When you can put any blade on your saw, tension it and turn on the saw without worrying about tracking, you'll be a believer, too.
Last edited by Mark in Burlington; 12-27-2007 at 11:52 PM.
The "Band Saw Handbook" by Mark Duginske is a very good
reference book. If you are talking about the wheels being coplaner when you mention alignment then the way to do this is to lay a straight edge across the wheels as close to the hubs as possible. To be in coplaner the top & bottom rims of both wheels must touch the staight edge. Do this with proper tension on the blade with the wheels parallel to each other.To get them parallel you may have to adjust the top wheel tilt mechanism. In my case when setting up my new Delta 14" BS, the top wheel did not touch the straight edge when same was placed across the bottom wheel. My wife held the straight edge in place while I measured the space between the wheel rims & the straight edge. This measurement was the thickness of the washer I needed to bring the wheels to coplaner. When the wheels became coplaner, the blade tracked a little closer to the front edge of the wheel. I also found that in my case, the saw no longer had a tendency to drift from the cut line when sawing. I believe the saw runs better since setting the wheels coplaner.
I have heard the theoretical argument that having to co-plane the flywheels is not necessary because of the adjustments available to compensate.
Conventional wisdom from most band saw gurus says that you will benefit from the exercise. One has to be cautious of either accepting conventional wisdom blindly or of summarily dismissing it.
My personal experience. With a Delta 14" saw, it cut wood just about as well before and after the adjustment. However; getting the blade to track and stay in alignment was a much easier task after the coplanar adjustment. The adjustment didn't make the saw work better, just less work to use.
FWIW. Try it. You have little to lose but an evening and then you will know.
Last edited by John In Waterdown; 12-28-2007 at 12:20 AM.
Something that is hardly ever mentioned is co-planar means the wheels are on the same plane vertically and horizontally. If the wheels are out horizontally then a simple shim will not fix the problem. So when checking with a straightedge do it near the centre of the wheels and also out on the front and back rims. If there is any difference out on the rims it means there is a twist either in the frame or caused by bad machining. Either will not be solved by inserting shims or moving a wheel on it's axle.
My big ol' General has adjustments built in to the top wheel carrier which allows correction. Maybe something worth looking for when selecting a bandsaw.
I found that both of my saws, the Rockwell 14" and the General 20" will now resaw without setting the fence at an angle to compensate for left or right drift. Something that was impossible before making the adjustment. Plus every blade tracks dead centre on the wheels without having to adjust the tracking after a blade change.
I think it's all in understanding---coplanar--straight--true--in line--etc etc etc. If as on a table saw--the wheels (which hold the blade) and the (arbor which hold the blade) are not set true-- straight coplana--in line--etc etc how are you ever going to cut in a straight line. The faised centre of the bandsaw wheels are only there so that the blade can be adjusted to run true to the wheels and to compensate for drift caused by the user applying force against the blade. As one poster put it---if everything is set coplanar and true and straight to a common point----then there is no drift when cutting.
So the common point would be --------the fence---and the mitre gauge can be set off the fence. I use the fence on the bandsaw because its easier than trying to measure square on the blade. On the table saw the blade should be parrallel to the mitre gauge slot and the fence.
Some people say there should be some runout on the table saw but I disagree---with todays top of the line blades I think its unnecessary.
In any case the cutting edge has to run true to some common point on the tool in order to use the mitre gauge and the fence. If everthing is set properly then staight rips and square cuts are the result. It takes time to set properly but it's worth it.
I have a line "you can't borrow my tools, it took to long to set them up but my ex-wife lives across the street!"