Show new idea for polishing by introducing steel balls into a rumbling rambling barrel says the engineer it to Is pos possible to polish castings and in fact actually to burnish them to a very high degree since the process ts la completely mechanical it can un bo be introduced in many brass foundries with the result ot of saving labor costs it II appears to be customary to use enough steel balls to malto make up approximately twice the volume of the pieces which are rumbled the size of the balls ran ranging gang from one quarter inch down to one sixteenth inch in diameter |