Weld-on hubs are made of low carbon steel for good welding compatibility. They are useful for welding into fan rotors, impellers, agitators, etc., which require secure mounting to the shaft. A standard type is available in addition to one that is specifically designed for use in the end disc of a conveyor pulley. Dodge Weld-On Hub, QD Type SF, 3.13 in Bore Dia, 5 in Outside Dia, 4-3/4 in Pilot Dia, 3.88 in Bolt Circle Dia, 3 Bolt Holes, 1 in Overall Length, Steel For use with type SF bushing