Sprocket Bore Diameter 5/8 in For Chain Pitch 1/2 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 7/8 in Number of Teeth 20 Outside Diameter 3.46 in Pitch Diameter 3.196 in Bore Type Plain Chain Number 40 Finish Black Oxide For Pitch Type Single Pitch Hub Diameter 2 5/8 in Hub Projection 0.716 in Includes Set Screws Keyway Yes Keyway Depth 3/32 in Keyway Width 3/16 in Length through Bore 1 in Material Grade 1045