Constructing a Home Made Ball Mill
I used old wringer washer rollers because they were 5/8" diameter shafts which are a standard size for bearings.
You can see the pillow blocks at each end of the rollers. The frame is 1/8" angle iron welded together.
The big pulley is from an old Maytag washer. The belt is 3L. The motor is from the Surplus Center and is a permanent magnet DC motor. This allows me to control the speed with a router speed control from Harbor Freight. You will also need a full wave bridge rectifier from the Surplus Center to convert the AC to DC.
Notice the jar is tilted a few degrees. This prevents the jar from walking off the rollers. You can also see a small roller bearing on a shaft that stops the jar from moving too far to the right.
I also installed an on-off switch for ease of use. The legs have rubber tips to keep the mill stationary on the floor as it mills.
Here is a closeup of the pillow blocks (cheap stamped metal is good enough for this light load and low speed).
Here you see that the roller to keep the jar from walking into the pulley is nothing more than a standard sealed electric motor bearing pressed onto a piece of shafting welded to the frame.
Here is an even clearer view of the mount. Notice the pulley just uses a large grade 8 fine thread bolt to hold it to the shaft. Strong and tight!
This is a view of the permanent magnet DC motor with its tiny pulley. It has no trouble running 24 hours a day, seven days a week. The 3 gallon jar I am using can grind 22 lbs of feldspar in a 24 hour period down to sub 200 mesh.