Seem to remember a thread...possibly, use a steel pellet tin with a good few but only one layer of lead balls, load it a simple grinding paste - with some chalk and oil, then use a top hap/ plunger type made out off a piece of circular cut ply with a hole through the middle to take a long countersunk bolt/nut...mount top hat/plunger thing in a drill and use it to press down on and spin those balls down to size in the pellet tin!...think it went something like that?