Universal Tumbler Machine

thingiverse

You can use any drum size, as the weight is entirely dependent on the ball bearing. Eighteen twenty-ball bearings and eight-millimeter rods are required, along with a gear motor. Any uncentered shaft gear motor will do; just add an adaptor, and adjust the motor shaft by moving the bracket. The design minimizes parts to print and time, making it simple to assemble and requiring less maintenance. Inside the drum, you'll find a vin stl file; print it and glue it in place.