When testing the wear of drill bits, there is a number of wear models that are mainly used in the processing of metal materials. During operation, the drill bits are exposed to high mechanical and thermal stresses, and by coating the drill bit, the resistance to wear increases. The most common coatings used when coating drills are PACVD TiN and PVD TiN. In the theoretical part of this paper, the high-speed steel which the drills are made of, their microstructure, heat treatment and vapor phase coating procedures are described. The geometry of the spiral drill blade and the cutting force during drilling are described, as well as the wear processes of the drill bit. In the experimental part, high-speed steel drills were coated with PACVD TiN coating. The microstructure, hardness, thickness and adhesion of the coating were tested on the coated drill bits. A series of drills were performed on an aluminum disc with an uncoated drill bit, a PACVD TiN coated drill bit, and a commercially available PVD TiN coated drill bit. During drilling for a total duration of 120 s, the wear of the drill bit was documented with light microscopy every 30 s. The temperature of the drill blade and the aluminum disc was measured with a thermographic camera. Both types of coated drills showed less blade wear than uncoated drills. The drill bit with PACVD TiN coating heated up more when drilling compared to the uncoated drill bit and drill bit with PVD TiN coating.