A ball mill is used to grind materials into powder. The basic idea is to have a rotating cylinder with steel ball bearings inside. As the cylinder rotates the bearings rub against each other creating friction and grinding whatever is between them. For flammable or explosive materials, ceramic non-sparking bearings are used.
- Plastic cylinder or coffee can
- Motor and gears from a broken shredder
- Ball bearings
- Mount for motor and cylinder