The shearing of the chips in a blind hole thread presents a particular problem in machining industry. The tap geometry plays an important role in the tool's durability, influencing the forces during the tapping process and also the way in which the chips are evacuated. This paper analyzes the influence of the tap geometry on the cutting of materials such as C45, 42CrMo4 and X5CrNi8. An adequate geometry will extend the tap durability by controlling the chip when the tap reverses while still engaged in the tapping process. It relates to the improvement of a spiral tap drill, which discharges chips towards the shank via a helical flute. The article contains details about the tap geometries and the results obtained in this research. Based on the results obtained in this research, the purpose of this paper was achieved. The tap durability was improved, the chip deposition on the rake surface was reduced and the torsion torque has a smaller value compared to the standard tap geometry.

The improvement of the microgeometry became a subject of a great interest in cutting tools optimization. This paper approaches the process of cutting edge preparation of solid carbide reamers. It has been analyzed the evolution of cutting edge wear resistance in the material GGG 40 using the scanning electron microscope (SEM). The work also compared the rounded cutting edge reamers realized using wet abrasive jet machining with standard unprepared cutting edge. To obtain different microgeometries were experienced a number of machining strategies, which resulted in four combinations of roundness and forms for the cutting edge. In order to validate the results, the author studied the wear resistance during the reaming tests, the influence of prepared surface of the cutting edge on metallic coating layer adhesion. The final purpose was to determinate the optimal strategy of cutting edge preparation considering the evolution of wear during the reaming process.