Bandsaw shaking intermittently?

[Tai Fu]

My 18 inch bandsaw with woodmaster CT, at a really high tension can run so smoothly that it would pass the penny test, however sometimes while running it will suddenly become shaky and shake like crazy, and then several more minutes of runtime (which really depends) the shaking will go away. What do you think is happening? I checked everything and it seems to be in order, however I have not checked if the wheels are coplanar because I don't have a way of doing that.

[david brum]

I would check to make sure that the motor pulley set screws are tight. It sounds a bit like the pulley might be walking around on the motor spindle.

[Tai Fu]

I Suspected it might be the case, but the pulley set screw is as tight as it could be... however for some reason there was only one set screw instead of two. Had no idea that the pulley position made such a big difference because without a blade the saw runs fine no matter where the pulley is.

[Dan Hintz]

at a really high tension can run so smoothly that it would pass the penny test

Make sure you're not running your saw with an unnecessarily high tension. You'll wear out the bearings pretty quickly that way, and you receive no benefit compared to running at the proper tension.

[Myk Rian]

Harmonics.
Have you checked the balance of the wheels, without a blade on it?

[Tai Fu]

I did, it appears to check out, but honestly I don't know how it works. I tried the marking with tape method (to see if the tapes all fall into a cluster or all over) and it's not conclusive. I tried that test by placing a lead wheel weight on the bandsaw wheel (to bring it out of balance) and it does NOT affect the test at all (tape mark still all over rather than in a cluster). Besides, the wheel was computer balanced at the factory and there are holes drilled in the back for this...

[Brian Kincaid]

How old are the tires? My tires would slip in and out of the grove when they were about to give out.
-Brian

[Myk Rian]

I did, it appears to check out, but honestly I don't know how it works. I tried the marking with tape method (to see if the tapes all fall into a cluster or all over) and it's not conclusive. I tried that test by placing a lead wheel weight on the bandsaw wheel (to bring it out of balance) and it does NOT affect the test at all (tape mark still all over rather than in a cluster). Besides, the wheel was computer balanced at the factory and there are holes drilled in the back for this...
If the wheel stops at different places with a lead weight attached, then the bearings are bad.

[Tai Fu]

Tire is fine, no flat spot or slippage that I can detect, and I doubt the bearings are bad, but how do I know if they are?

The drive pulley affects things a lot though... I've experimented with moving them around and the bandsaw goes from shaking like crazy to not at all.

[Myk Rian]

I've experimented with moving them around and the bandsaw goes from shaking like crazy to not at all.
Moving what around?

[Tai Fu]

The drive pulley position

[Myk Rian]

OK. I'm missing something.
Going to bed. Maybe we can work on it tomorrow, after softball.

[Gus Dundon]

Put the drive belt back on and take the blade off. This will tell you if the problem may come from alignment of your pulley.

[Meryl Logue]

End result?

[Rod Sheridan]

Make sure both wheel shafts are secure in their mounts.....Rod