An attempt is made to predict the subsurface damage in the mach-ined components induced in metal cutting using a semi—analytical model based on the identation of a semi-infinite plate with a line load. A model is proposed to calculate the plastically deformed zone underneath the machined surface when cutting with sharp tools. Measured values of tool forces and the tensile yield strength of the material should be used in the analytical model. Experimental measurements were carried out to determine the depth of the plastically deformed layer using a simplified technique. The experimentally measured values agreed well with the depth predicted from the analytical model.