In this study, cutting speed V, feed rate f, depth of cut a and tool radius R of surface roughness R of hardened 42CrMo4 (52 HRC) material with ceramic insert having different Ra, Rz and Rt) and cutting forces (Radial force Fx effect) tangential force Fy and feed force Fz were investigated experimentally. For the experimental design, Taguchi's mixed-level parameter design (L18) was used (2x1.3x3). Signal-to-noise ratio S/N was used to evaluate the test results. Using the Taguchi method, cutting parameters and cutting forces giving optimum surface roughness were determined. Regression analysis is applied to predict surface roughness and cutting forces. ANOVA was used to determine the effects of machining parameters on surface roughness and cutting forces. According to ANOVA analysis, the most important cutting parameters were found to be the cutting depth between feed rate and cutting forces for surface roughness. Verification experiments were performed and it was observed that optimization was applied successfully.