Nomenclature of the Cutting Edge

This brief paper is put forward in an attempt to encourage a discussion on the nomenclature of cutting tools. Attention is drawn to various terms used to describe the angles of cutting tools, and a number of illustrations is given to show the nomenclature adopted in published work and by makers. It is suggested that for lathe tools, drills, milling cutters, etc., the most important cutting angle should be the same when the same material is being cut.The illustrations show that rake is used in a number of ways, but always has reference to the face of the tool over which the chip moves; in very few cases, however, has it clearly defined reference to the all-important angle measured on a plane at right-angles to the cutting edge. This is the angle that very largely determines the cutting effects of the tool and the authors suggest that it should be called the breast angle. Front rake, side rake, etc., may then reasonably be used, as at present, to define setting angles for grinding. The breast angle for any ...