Make a Ball Mill in 5 Minutes : 4 Steps - Instructables
Wiki says "A ball mill is a type of grinder used to grind materials into extremely fine powder for use in paints, pyrotechnics, and ceramics." Many instructables refer to United Nuclear Ball Mills. Their small ball mill cost between $70 and $80 dollars. For no more than $30 and in 5 minute you can build a ball mill of appreciable performance.