Type J flanges sizes 3, 4 and 5 are manufactured of sintered carbon steel. The powdered metal manufacturing process provides high dimensional accuracy and uniform material properties for high strength. Size 6 is made of high strength cast iron. Flanges are bored-to-size for a slip fit on standard shafts. The outside face of the flange is precision machined, allowing the surface to be used to align the coupling without special tools.