J Series 3 7/16" Finished Bore QD Bushing for QD J Series Sprockets, Pulleys. and Sheaves. QD Bushing, Black Oxide over C45 Steel Finish Standard Keyway 3 - (5/8-11 x 4 1/2) Screws Torque Capacity (lb/in) 45000. J QD (Quick Detachable) bushings are precision-engineered components used for mounting pulleys, sprockets, and sheaves onto shafts in power transmission applications. They feature a split, tapered design that provides a secure, concentric grip while allowing for easy installation and removal. The J size is one of the larger options, typically fitting shafts of around 1 1/4 - 4 1/2” in diameter. Made from durable materials like cast iron or steel, J QD bushings ensure reliable torque transmission and minimal shaft wear, making them ideal for industrial machinery, conveyor systems, and agricultural equipment.