Hi Villas, the cutting speed for using High Speed steel cutters, when cutting mild steel is, as a rule of thumb, for 25mm diam cutters 300 revs per minute. The smaller you go the faster the speed. So for 12.5mm diam the speed would be 600 rpm, and if it was bigger say 50mm then it would be 150 rpm. This is based upon the rule that High Speed Steel uses a cutting speed of 100 feet per min, which is an imperial setting. So 1" diam or 25mm diam tools are 300 rpm. |