A cabbing machine, also known as a cabochon machine or cabbing unit, is a specialized tool used in lapidary work to shape and polish gemstones into cabochons. Cabochons are gems that have a smooth, rounded convex top surface and a flat or slightly domed bottom surface.
The cabbing machine typically consists of a horizontally rotating lap or wheel that is coated with abrasive material. It may have multiple wheels of different grits to facilitate the shaping and polishing process. The machine is equipped with adjustable features such as speed control and water supply to enhance efficiency and precision.
Cabbing machines allow lapidary enthusiasts to perform a range of operations on gemstones, including shaping, grinding, smoothing, and polishing. Here are the primary steps involved in cabbing:
Shaping: The rough gemstone is initially shaped into a preform, which is a general outline of the desired cabochon shape. This is done by holding the gemstone against the rotating lap while applying pressure to remove excess material.
Grinding and Smoothing: Once the preform is established, the gemstone is further refined using progressively finer grits. This step involves grinding the stone against the lap to achieve a smooth and uniform shape.
Polishing: After the desired shape is achieved, the gemstone is ready for polishing. A polishing lap or wheel with a fine abrasive compound is used to create a high-gloss finish on the cabochon's surface.