The builder ran a machine shop and has retired. It was a tumbler used to clean rusty parts or sand blast parts without actually spending the time manually sand blasting. It's a home built job made with a propane tank, motor, chain. Runs nice and slow, maybe 15rpm to 20rpm. Quieter than I had expected...at least until I fill it with brass. If anyone likes it, I can post up closer pics/specs/parts list and a video of it running. Most of it would be easy for the novice builder, but I think the door might be tricky to build. I suppose its not an ideal set-up. Has its drawbacks. But for the money I think its awesome.