A ball mill is a type of grinder used to grind and blend materials for use in mineral dressing , Ball mills are also used in pyrotechnics and the manufacture of black powder, but cannot be used in the , At the same time, the grinding media particles should be substantially larger than the largest pieces of material to be ground.
Wiki says "A ball mill is a type of grinder used to grind materials into , For no more than $30 and in 5 minute you can build a ball mill of appreciable performance , shotgun balls work really good if they are of the lead variety , plus shipping or people who live outside america with no real ballmill suppliers come on man.