Diamond Pacific Heavy Duty Rotary Tumbler Jewelry Box plus three rubber inserts for SE MC118 180 plus three rubber inserts for the guide wheels and over 5 Diamond Pacific large rock tumblers are designed for hard use efficiency and long life These commercial rotary tumblers are ideal for tumble polishing large loads of stone light deburring burnishing peening cleaning and finishing metal parts For optimum action the barrel should be used approximately two thirds full of combined media and stones or parts If it is overfilled there will be very little tumbling action and if underfilled there will be slippage of material without any abrasive action Your stones or parts should be sorted for compatible size shape and hardness to ensure uniform sanding and polishing Tumbling is an art and a science and will require experimentation and practice to perfect your recipes for various materials There are many different tumbling machines and supplies available to adjust your techniques and equipment to the stones at hand