In this study, the performance and the useful life of a mixed ceramic tool with S-type edge microgeometry are evaluated for the case of dry turning of AISI 4140 steel hardened to 55 HRC. The influence of the cutting speed and feed rate of the cutting parameters on the tool failure was investigated. The experiments were designed and analysed using the complete factorial design technique. Our results indicate that the cutting speed and feed rate values exert significant influence on the tool lifespan. Crater and flank wear occur in all cutting conditions. The predominant tool wear mechanisms are diffusion, abrasion, and adhesion, which are also known as attrition. The tool life curve and equation were established for the machining conditions of this investigation to achieve the subsequent optimisation of this process.