This is a fully printable ball mill that does not require any supports. It was designed to use a 170 RPM motor and the mount fits this motor (https://www.amazon.com/dp/B00NQ8HXNA/).

In order to ensure a tight, dust proof seal, make sure to add an ring of silicone to the inside of the cap, to glue the hex shaft onto the drum and to glue the motor shaft to the drum.

It can be used to grind virtually any material into a fine powder.

Here is a video of it in action: https://www.youtube.com/watch?v=SLQzLVd98BQ&feature=youtu.be