Here is a different video showing the same idea:
https://m.youtube.com/#/watch?v=4skIIRlFeQw
Next I am building an annealing machine. I figured I would build 4 or 5 and put the rest up for sale on Youtube.
Btw, maybe I should start a thread on that when I get home and I take pics of the tumbler. If you are going to make one, don't bother with the power supply. Just plug the motor to any old car battery you got laying around. The motor doesn't draw all that much power from it anyways. And it will be less bulky without the power supply. Use 2 gal buckets. 5 gal is way too big unless you want to tumble brass and mix concrete for your next house all in one tool.