Very important cutting tool property is its durability. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-vc dependence. The article describes process how to create durability dependence for cutting tools made of sintered carbide by means of T-vc dependence in machining process of steel 100CrMn6.