To make certain prongs are down tight on the crown of the stone, hold the mounting at eye level and turn so that you are looking at the prong from the side view. Then, hold your index finger about 1 inch above the stone. This will shield direct light from the stone, causing a silhouette of the stone and prong. Then, you can easily see light coming through any gaps between the stone and prong. If you cannot see any light between the crown of the stone and the prong, your prongs are down tight, and no further tightening is necessary. Taping a 3 X 5 white index card on the wall in front of your bench helps as it provides a light background to hold the stone in front of.
How to training videos for Bench Jewelers
See some of the most respected Master Jewelers explain their techniques and tips
on stonesetting, making and repairing jewelry.