Coating failure in cutting is due to the formation of cracks as a result of elastic and plastic deformation of the tool edge (1-3). The deformation rate, in turn, depends on the thermal and stress state of the cutting edge. Therefore, in developing new wearresistant coatings, it is important to study the thermal and stress state of the cutting edge. In the present work, we investigate the influence of the composition of threeelement nitride coatings on the thermal and stress state of the cutting edge and its wear rate. A TiMe1 Me 2 N coating, where Me 1 and Me 2 are alloying elements, is applied by condensation (from composite cathodes) in vacuum, with ionic bombardment. We use aluminum, zirconium, and sil� icon as Me1 , and aluminum, zirconium, silicon, iron, molybdenum, and chromium as Me2 . The contact temperatures are determined by the method in (4). The stress state is estimated by the method in (5). The temperature and stress distribution in the cutting blade is plotted by means of ANSYS software. The wear rate is determined from the formula Additional alloying of the coatings with a second element increases the contact length Cγ of the chip with the front surface of the tool. Compared to TiMe 1N coatings, the greatest change in Cγ is 8-15% for coatings applied to hardalloy tools and 7-16% for coatings on highspeed steel tools. The increase in C c is greatest on additional alloying with Cr, Fe, Mo, and Zr and least when Al and Si are added. In turn, the increase in Cγ increases the plastic deformation of the chip, as confirmed by the increase in KL. Thus, KL increases by 3-9% for threeelement coatings applied to hardalloy tools, and by 3-10% for coatings on highspeed steel tools. The change in K L is greatest for the addition of Zr, Al, and Si and least for the addition of Cr, Fe, and Mo. The increase in plastic deformation of the chip in alloying with a second metal Me2 increases the com� ponents P x , P y , and P z of the cutting force. The increase in Px, Py, and Pz as a function of the Me2 con� tent is the same (Only the data for Pz are presented in Table 1.) Thus, for TiAlMe2N coatings on hardalloy tools, the increase in the cuttingforce components is