Energy consumption has been a significant issue. CO2 emissions have increased due to increased energy consumption. On the other hand, hard steels have been an essential subject of investigation due to their low energy consumption and good surface quality. Therefore, this experimental study investigates the effects of cutting parameters on cutting forces, power consumption (PC), energy consumption (EC), sound intensity (SI), and surface roughness (Ra) in machining AISI S1 (60 HRC) cold work tool steel. Feed rate (f) on cutting force with 53.23%, power consumption with 94.11% depth of cut (ap), energy efficiency with 74.92% feed rate, over surface roughness value with 86.66%, depth of cut with 94.42% on sound intensity are effective parameters. Mathematical equations related to the cutting parameters were obtained. In addition, mathematical equations were created between cutting force and power consumption, cutting force and sound intensity, and power consumption and sound intensity. Finally, optimum cutting conditions were determined with multiple optimisation methods, which turned out to be 210 m/min cutting speed (v), 0.08 mm cutting depth, and 0.0505 mm/rev feed rate. Accordingly, it was calculated that sound intensity would be reduced by 4.25%, surface roughness value would be decreased by 36.36%, power consumption by 21.74%, Fz by 26.77%, by Fy 52.46% and Fx by 24.44%.