Shaft-type mechanical components category that transmits rotational motion. Handles a wide range from power transmission shafts such as motor shafts, main shafts, drive shafts, driven shafts, and intermediate shafts, to precision machinery shafts including ball screw shafts, spindle shafts, and linear shafts for NC machine tools. Materials range from machine structural steels like S45C and SCM440 to stainless steel and aluminum alloys, including various machined products with keyway processing, spline processing, and thread processing. Combined with bearings to form rotating mechanisms, these are critical component groups that play a central role in power transmission systems of manufacturing equipment.