Dry Laboratory Ball Mill

Inexpensive ball mill, about 4" / 100mm in diameter. I use a 5 volt 28BYJ-48 stepper motor and .5" glass marbles for the ball media. A PIC 12f675 / ULN2003 drives the cylinder at 45RPM. The powdered product tends to leak a bit. I place a dish under the mill to catch this.

I replaced the 5 volt stepper motor with its 12 volt counterpart. I've had less stalling issues with this setup.

Printing:
PLA
25 % infill on all parts except center.
Center setting: 0% infill. No top / no bottom.

Additional parts:
2 x 608ZZ bearings
6 x 4-40 x 2" stainless steel machine screws and nuts
1 x 28BYJ-48 stepper motor and driver
2 x #4 x .375" sheet metal screws
CA glue.