Abstract Presented in this paper is a model which enables the prediction of the specific cutting force and the cutting force ratio in metal cutting, based on a predictive machining theory using a shear-zone model of chip formation. An important feature of this model is that the variations of the flow-stress properties of the work material with strain, strain-rate, and temperature and of the thermal properties of the work material with temperature and chemical composition are taken into consideration. Good correlation between the predicted and measured specific cutting forces and cutting force ratios in the turning operation is demonstrated.