The conventional model of orthogonal cutting with type 2 chip is modified to include the effect of deformation of the work-piece at the immediate vicinity of the tool-tip. The cutting velocity condition for optimal force of deformation is examined in the light of two alternate criteria: recrystallization temperature and melting temperature. It is shown that a critical cutting velocity exists. Furthermore, it is concluded, in part, that proper metallurgical treatment and/or preheating the work-piece (hot machining) will improve cutting.Contributed by the ASLE Technical Committee on Lubrication Fundamentals and presented at the Annual Meeting of the American Society of Lubrication Engineers held in Pittsburgh, Pa. April 1956.