QD Bush Pulley

The main difference in the two kind of bushing (Taper & QD) is that the QD style bushing has a flange around the outside diameter, while the taper lock bushing has straight sides on the OD. Many people refer to both types as a "taper lock" because they both use the tapered wedging action to lock to the shaft, The taper lock bushing, with it's straight sides, uses an internal hex head cap screw to drive the bushing into the bore of the component being installed (sheave, sprocket, etc.). While QD bushing with flanges around the OD, uses external hex screw to drive the bushing into the bore of component being installed. This gives OD bushing larger bore capacity than Taper Lock Bushing for the same pulley drive, Also, because of external keys, pulleys with QD bushing have greater torque carrying capability.