The document discusses cutting tool materials and Merchant's Circle Diagram (MCD) for calculating forces in machining. It provides information on 7 common cutting tool materials: high carbon steel, high speed steel, cast alloys, cemented carbides, coated carbides, ceramics, and diamonds. It also explains what MCD is and how it can be used graphically to calculate cutting, tangential, friction, normal, shear and normal shear forces from measured cutting forces. An example calculation using MCD is provided.