Weld on hubs are suitable for use in many applications, such as welding to plate steel sprockets. Type WA weld-on hubs are made of steel, drilled, tapped and taper bored to receive tapered bushings. They are very useful for welding into fan rotors, pulleys, plate sprockets, impellers, agitators and many other devices which must be firmly fastened to the shaft. Martin Weld-On Hub, TB Bushed Type WA, 4-1/4 in Bore Dia, 5-1/2 in Outside Dia, 5-1/8 in Pilot Dia, 4 in Bolt Circle Dia, 2 Bolt Holes, 3 in Overall Length, Steel