Creating A Decorative Feature

BENCHTIPS

- BOB RUSH

This column outlines a step-by-step project to create a decorative feature on the back of your cabochons using small burrs that mount in a flex shaft. It involves using diamond ball burrs of various grits and homemade wood burrs.

The first step is to select a translucent area on your cab or slab that shows considerable transmission of light and color in the place where you will make the decorative feature. Mark a point with a felt tip pen and start the hole with a small coarse grit 1/8-inch diamond bur. I do the carving in a shallow plastic bowl cut from the bottom of a large plastic bottle with ½-inch of water inside. Dip the piece in the water and grind with the burrs for a few seconds and dip again.

Using a ½-inch diameter coarse burr, continue the grinding by holding the side of the bit in the previously made hole. Continue dipping and grinding for a few seconds. Every few minutes, turn the burr vertically and correct the shape of the hole because when you grind with the side of the burr, it pulls slightly sideways. Ball burrs do not grind very well if you hold them vertically.

As you are grinding the hole, stop and look at the back of the piece under a strong light to see how it appears. If you like how it looks, begin the sanding steps to remove the grinding marks.