Ball Mill From Mainly Recycled Parts : 11 Steps Instructables
When ball milling, always use about 2/3 balls by volume. Make sure the drum isn't going too fastsay 2 revolutions per second, max. It helps to glue a couple of wooden "paddles" inside the drum to aid mixing. If the drum goes too fast, it will no longer tumble and drop the balls, but just throw things outward due to centrifugal force.