Everyday practice of cutting process planning requires reliable cutting force estimates, which currently can be obtained only from process-dependent machinability databases. The greatest obstacle to developing a more basic, efficient approach is a lack of understanding of material behavior under unique deformation conditions of cutting. The metal cutting process has been defined by the authors earlier as the purposeful fracture of workpiece material and, therefore, a new way to minimize the energy consumption per unit volume of the layer to be removed in cutting should be revealed in order to predict metal cutting performance. Unfortunately, the traditional mechanical metallurgy has too little to be used for such a purpose. This paper deals with practical applications of the equation of state of a solid to the metal cutting process. It is shown theoretically and proven experimentally that the energy consumed in cutting can be effectively controlled by applying external force fields to the workpiece.