Here's the body of the ball mill, an old galvanized water cooler that was no longer useable for drinking water. I used a bunch of J-B Weld and welded some pieces of angle iron to the inside for mixing paddles.
This is the cradle that the mill rests in. The wheels are from an old pair of rollerblades. As you have probably begun to suspect, I'm compelled to re-use anything I have that appears even remotely useful.
The can sitting in the cradle. The pegboard on each end is just high enough to keep the can from working its way off either end.
This is the motor for the ball mill. This is a motor and gearbox from a food processor. The motor turns at full speed, but the output gear turns slowly. Originally it was going to just be a friction drive against one of the wheels, but that wouldn;t turn the can when it had a load in it. Eventually what I ended up doing was J-B Welding some bicycle gears to the end of the can and the output of the motor.
Eventually I had to add some machine screws to keep the lid on while the can was turning.
Here is a 3.2 meg .avi file of the ball mill in action.