RIkon 10-325 Bandsaw Upgrades and Mods, Pt. 2: Coplanar Wheels

Now that we have new tires on the bandsaw wheels, we can take a stab at making them coplanar.

Basically this means making sure the wheels are running in the same vertical plane. We'll use some shims to adjust the bottom wheel out if needed to get it to align with the top wheel.

This whole idea of the wheels being coplanar is a bit controversial. Some folks insist it's not critical, while others believe it's important for good blade tracking. I have a couple of books that recommend it, and it seems to me to be logical that if the wheels are in the same plane, the blade will ride in the same place on both wheels. In other words, if the wheels aren't coplanar, the blade might ride in the center of one wheel and the edge of the other.

My new tires (and I believe most tires) have a crown. It just seems to me that you'd want the blade to ride at the same place in reference to the crown on both wheels. This also follows Alex Snodgrass of Carter Products' setup suggestion on having the blade ride on the crown. If the wheels (and tires) aren't coplanar, the blade can't ride the same way on both wheels.

To check the alignment (coplanaredness?) of the wheels, you need a straightedge that is long enough to touch the rim of both wheels. I have a drywall T-square that's long enough, but because of the way the frame of the saw juts out between the wheels, I had to cook up a spacer so the square would clear the frame.

This is what I did, primitive but reasonably acccurate. See the picture on the left, just two wood blocks 1.5 inches thick held onto the straightedge with rubber bands.

Here's how I used my fancy coplanar gauge.

Put one wood block on the top wheel, touching the rim.

You have to be sure to keep the straightedge exactly vertical/plumb or it won't be accurate. My T-square is aluminum, so it wants to flex. I just let it hang and checked it with a bubble level.

Again, a bit primitive, but it worked.

And this is the bottom wheel. I may have taken this shot after I put the shims on, as it looks like the block is touching the wheel.

When I first measured, the bottom wheel was back from the block about 1/4 of an inch (about 6mm)! I was surprised it was off that much.

If you have a 1/2 inch blade tracking on the wheel, and the bottom wheel is back 1/4 of an inch, that's a lot. The blade would be riding on the outside of the bottom wheel...not a good thing.

I mentioned shims. I used some 316 stainless steel washers from McMaster-Carr. You won't find these at the Despot. I went with stainless because I figured they would be strong and wouldn't corrode over time.

On Asian-made saws such as this one, the bottom wheel is the one to adjust. On U.S.-made saws, it's the top wheel.

Here's my stack-o-shims installed on the axle of the lower wheel. I lubricated them with "Super Lube" light grease. Just a thin coat - I don't want to attract sawdust and dirt.

The axle shaft is just long enough that the wheel will still mount with no problems using the retaining c-clip.

I checked the alignment after I put the shims on, and it was good.

So I put the wheels and the blade back on to test the saw, and found the drive belt kept slipping off after a few seconds.

After pondering this problem, I realized the motor pulley was now out of alignment (duh) with the pulley on the wheel by the amount I had shimmed the wheel out by.

So I just undid the pulley retaining allen screw  and slid it out to align. You can see I had to use vise-grips to hold the pulley while I loosened the screw - it will rotate otherwise. The belt doesn't jump off now that it's aligned. Also note the tension pulley above the motor pulley. It's wide enough that the belt still rides on it with no problem.

Next time we'll get the Carter guides on and take the bandsaw for a test run.