Tapered sockets are designed for rapid assembly and disassembly of pulleys and other transmission products without the want for special instruments other than a hex essential. Different machined holes make sure quick neighborhood, avoiding high priced manufacturing facility downtime. Bushings are keyways machined to British Standard Specs. This is in addition to the clamping screw, which is ample for the needed torque in a lot of cases. Tightening with a tapered bushing removes any hole amongst the hub and the bore, which eradicates fretting corrosion.