bandsaw clunking noise

[Andy Bourgeois]

I recently got a used Jet 18" bandsaw and when I tried it out before buying, it sounded fine. When I got it home now thought, there is a clunking sound.
I've isolated the sound to the lower wheel -- I disconnected the drive belt and removed the blade and can recreate the sound by manually turning the lower wheel. The clunk does not occur at the same wheel position every time.

Any ideas? Could this be a bad bearing?

[brian noel]

At first I thought it might be a bearing, but I am not sure. here is a diagram http://www.ereplacementparts.com/jet-jwbs18-708750-woodworking-bandsaw-parts-c-32652_32684_282344.html
Try taking the motor belt off the lower wheel and rotate it again and see if that does anything. There could be something in the motor housing, it could be the shaft, but my best guess is its a bearing going out.? Hope that helps.

[glenn bradley]

I'd lean toward a bearing as my first check. If you grip the wheel like a steering wheel and try to wiggle it on the shaft, is there movement/clunking? the lower wheel alignment mechanism could also come into question.

[Arek Kosinski]

I had a different problem and my solution was new tires. I left 2 my band saw fully tensioned and it flattened the tire. You might have the same problem, worn or flattned tires.

[mark kosse]

Did you bend the blade bringing it home?

[Shawn Christ]

Did you bend the blade bringing it home?
That was my first thought too.

[Lee Schierer]

It sounds like a dry bearing. Sometimes the grease in bearings builds up a thickened layer on the race at the point of contact of each of the rollers or balls. Usually this layer will go away with use, but sometimes it becomes almost like varnish on the race and you get a clunking noise. Put a couple of drops of oil on the shields and let it soak in. Repeat this once or twice for a day or two and see if the noise goes away. I had a similar problem on my table saw after it wasn't used for several months. The arbor would make a clunking sound as it slowed down. That was more than 10 years ago and it is still going with no play in the arbor.

[Andy Bourgeois]

Thank you everyone for the advice!
It was the one of the four adjustment screws for lower wheel alignment. I just kept removing parts until I isolated the noise. Still clunking after the drive belt and blade were removed. I then removed the drive wheel and blade wheel... still clunking when I spun the shaft. I removed the shaft/bearing assembly and it seemed to spin freely. When I reassembled everything, I backed the adjustment bolts all the way out then re-tightened, and the noise stopped. One of them must have been slightly loose letting the assembly rock back and forth. It must have backed out during the ride home since it was pretty quiet before.