Jaw Coupling Hub Coupling Size JC21 Outside Diameter 1 5/16 in Coupling Overall Length 1 3/4 in System of Measurement Inch Hub Material Aluminum Maximum Speed 8 000 RPM Keyway Depth 3/32 in Keyway Width 3/16 in Bore Diameter 5/8 in Shaft Locking Type Clamp On Bore Type Round Bore with Keyway Jaw Profile Curved Screw Thread Size M3 Bore Tolerance +0.002/-0.000 in Fail Safe Yes Shaft Tolerance +0.0000/-0.0005 in Full Bearing Support Required Yes Hub Diameter 1 5/16 in