The oscillating roller is hanging up at one point in its travels. Fritz wrote that this is probably due to damage somewhere on the worm gear, the center shaft of the oscillating roller. He was right; one of the points on the worm gear was chipped, and that is where the crescent rider is hanging up. I was able to get back up and running temporarily by backing off on the set screw that holds the crescent in place, but yesterday, the roller refused to get around that bad spot. I was able to file the worm gear down a bit, but Fritz is right; the gear is hardened steel and does not go gently under the file. My question is: does this mean I have to get a new worm gear? Does a new one exist?? Can I try filing some more? Would a machinist be able to hone that point for me? Thanks.