Copper wheel engraving is a traditional technique which requires a belt-driven lathe carrying a range of inter-changeable spindles, each mounted with a wheel made from copper. Each wheel varies in width, diameter and profile so as to make different types of cut in the glass. A slurry of carborundum grit, oil and paraffin is applied to the turning copper wheel and the glass is held against the wheel to make the cut. Coarse grit is used for rapid and large scale cutting, fine grit for more polished, delicate work. Most engravers now also use stone and diamond impregnated wheels. In the past, the lathe was driven by a foot pedal, now usually by an electric motor. The copper wheel creates a very precise cut and was the tool originally used for traditional cut crystal designs.