A New Approach to Determination of the Shear-Plane Angle in Machining

A reevaluation of the minimum-energy type of solution for shear-plane angle has been made, without reference to a coefficient of friction. It is proposed that the shear plane will be oriented at an angle such that the total work done in plastic shearing of the metal, on the shear plane and at the rake face, has an extremum value. A full solution for nonhardening material is obtained, and this is extended to provide a qualitative explanation of chip thickening and the formation of a built-up edge with strain-hardening material and high rake-face stress. The importance of the length of contact on the rake face is emphasized.