Lapidary Fundamentals: Gemstone Faceting .
Now, turn on the water and machine again. Gently introduce the stone to the lap and sweep it back and forth across the surface. Don''t use much force. Apply just enough pressure to keep the stone in contact with the cutting surface. When you''ve cut all the way to your depth setting, the sound will change. It will go from a grinding noise to a "shhh" sound. If the pressure you''re using ...