I have a Chicago Electric vibratory tumbler which my wife bought me for Christmas two years ago. This tumbler has worked very well 'til now, but I'm not sure what I've done to it. I will try to describe the problem as well as can and add pictures to help: The other day I was tumbling brass when I noticed the drum on my tumbler was spinning freely and seemed to be loose. I gave this nut a quick twist to snug it up. About 45 minutes later I went to check on the brass and found the metal washer and rubber bushing had started wearing a hole in the lid. The metal rod to tighten the lid down was very hot to the touch and had also been worn. I'm guessing I screwed something up by tightening the nut down too much. Does anyone have any experience with these tumblers, or had anything like this happen to them?