An attempt is made to apply the method of reliable assessment of wear and reliability of drilling tools, and the results of comparative studies of wear are presented. The wear of carbide pins is compared with the wear of the body material. During the running-in period of new crowns, uneven wear of the pins was observed, which was further leveled after 30 hours of total machine operating time. The reasons for the premature destruction of crowns as a result of manufacturing and assembly errors are described. The nature of wear in various types of drilling is considered. The reliability calculation formulas and the recommendations for the design and operation of drill bits made of tool steel and equipped with carbide cutting elements are given. Within the study, the wear of seven standard sizes of pin bits with a diameter of 30–50 mm, equipped with pins made of VK-8 material for drilling eluvial and redeposited ferruginous quartzites of various types (iron mica and martite-hydrohematite) was investigated. The ore body composed of the above-listed ores, is characterized by a wide variety of physical and mechanical properties. These properties affect the wear of bit pins and the reliability of tools and machines in general. Ore and gangue can alternate randomly, therefore, in the interbeds of carbonated rocks, tools experience increased wear and high temperature at the tool–rock interface. Productivity of process well drilling depends significantly on the reliability of the drilling machine, assembly and tool. Accidental breakdowns and increased wear of tools, as well as failure of the machine and equipment assemblies as a result of high loads often take place in drilling. Breaking of pins and their falling out under the influence of high temperature is also observed, which weakens the interface between the pin and the crown body. Alongside with random and wear failures, their integrated effect on the performance of technological operations is discussed. The calculation formulas are given.