While the term lapidary refers to stones and gems (lapidarius is Latin for "stonecutter"), lapidary tools and equipment have found their way into many glass artist's cold-working studios.
Included among these tools are flat lapidary grinders – often referred to as lap grinders, flat laps and flat grinders.
Flat laps are typically constructed with a thick, steel plate mounted on a motor so that the plate turns like a record on a record player (remember those?). The abrasive is provided by either a slow stream of grit slurry (typically the water and the same silicon carbide used for sand blasting) or there is a diamond grit disk that attaches magnetically to the spinning steel plate.
A variation on the traditional flat grinder is the vibratory lapidary grinder. Similar in appearance to flat grinders, the plate on these machines turns slowly while vibrating. The object to be ground and polished is placed on the plate with a grit slurry. As the object vibrates over the slurry it is ground flat and polished. Vibratory lapidary grinders have the advantage of being able to run unattended and being inexpensive to operate. The disadvantage to vibratory laps is that the whole process can take several hours – to several days – to complete (compared to minutes with an expensive diamond flat lap).