The thesis consists of two parts; theoretical and experimental. The first (theoretical) part describes tool steels, their division, main properties, and differences between alloying and non-alloying steels. Following that, tool steels for cold work and their main division are described in detail, as well as the associated heat treatments used in this work. Also, machines and their working principles on which samples for heat treatment were prepared are described. The vacuum furnace in which the hardening process was performed and the eccentric of the bar on which the tool from this work is used is described in detail. The experimental part consists of testing various heat treatment procedures to determine the optimal properties for high-alloy ledeburite Cr-V tool steel with molybdenum addition. First of all, it was necessary to prepare samples from the raw material by particle separation processing (milling, cutting, grinding) in order to obtain 8 identical samples for testing. After that, heat treatment was performed on them numerically marked from 0 to 7. Sample "0" indicates the basic state of tool steel (X155CrVMo12-1), while other samples were subjected to the hardening process. After hardening, each sample was heat-treated in a different way to show the differences between different heat treatment processes. At the end of the experimental part, the hardnesses of all samples on the hardness tester according to Rockwell were tested and the manufactured tool was tested in operating conditions in production in the company Auspuh Lastovčić d.o.o.