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.