The use of stereographic projection for describing the geometry of cutting tools — Part II

Abstract

Part II describes the use of the stereographic projection for displaying the angular geometry of various types of cutting tool. It is shown that the projection provides a simple method for describing the working geometry of tools; all faces can be represented on one stereogram together with the direction of cutting, the axes of the tool holder and those of the machine. Any desired angle such as normal rake angle, inclination angle etc. can be measured directly from the projection using a graphical technique. The case of a single point turning tool set into a machine at a compound angle is considered in detail; it is shown that the “working” cutting angles obtained depend on the design of the tool holder. The method is also given for obtaining the necessary tool setting angles to cut with prescribed “working” angles for a particular tool geometry. The use of the projection for describing curved faced tools is more limited but it is shown that it has application in this case also. Examples are given of the determination of the “working” cutting angles of a twist drill and a tap.