In this experimental work, focuses on the investigation of the effect of cutting parameters on surface Roughness and to minimize surface roughness. The experiments have been conducted by a CNC lathe machine. Dry turning tests are carried out on hardened steel with coated carbide cutting tools. This study sought to give systematic and trustworthy techniques for manufacturers and engineers to efficiently optimize machining parameters, tool selection, and process conditions by using Taguchi Design Optimization. The experiments revealed that the most favorable combination of cutting parameters, which resulted in a minimum surface roughness of 2.6 µm, corresponded to a cutting speed (V) of 120 m/min, a feed rate (F) of 0.2 mm/rev, and a depth of cut (D) of 0.08 mm, yielding an S/N ratio of -8.29947. The utilization of coated tools has been identified as beneficial for enhancing the machining of hard materials when employing higher speeds and reduced feed rates. The findings from this research reveal that the feed rate plays a paramount role in influencing both Ra and Rz. Furthermore, it is noteworthy that the interplay between two factors, namely the feed rate and cutting speed, as well as the depth of cut and cutting speed, exerts notable effects.