Carborundum
A substitute for diamond powder, used in polishing. It is made in two grades. No. 1, which is an olive tinted powder, is used by lapidaries for polishing the facets of gems, as it is so much finer than diamond powder that a superior finish can be secured on the gem by its use. It is also much cheaper than diamond powder. No. 2 is a black powder, which resembles the other in hardness, but is impure and still cheaper. It has extensive use among metal workers as an abrasive. Both varieties are used by watchmakers in the various polishing operations, as substitutes for diamond powder, bort, diamantine, etc.
CAM. A moveable piece of irregular contour, so shaped as to give a variable motion to another piece pressing against it by sliding or rolling contact.