The analysis of the cutting area circuit diagram has shown that coatings on the edges of the hole and on the flank surface of the tool change the thermoelectric power measured by the dynamic thermocouple to the value of not more than 0.3-0.7%. So, only the composition and properties of the coatings will have an effect on the cutting temperature. Model theoretical temperature calculations according to the dependence proposed by the authors have shown that the temperatures are minimal when using single coatings ZrO2, TiN, AlN (for couples Т15К6 — St45), and ZrN, AlN, ZrO2, Al2O3 (for couples Т15К6 – 12H18N10Т). Experiments on turning St45 by carbide plates made of T15K6 have proved the efficiency of TiN+AlN coatings when the cutting temperature, chip shrinkage, and contact length on the front face (lc) are less than for the base alloy T15K6.