Shaft Collar System of Measurement Inch Bore Type Round Bore Diameter 1 5/16 in Bore Thread Size Not Applicable Collar Outside Diameter 2 1/8 in Inside Height to Flat Not Applicable Clearance Diameter 2.35 in Collar Width 9/16 in Collar Material Aluminum Keyway Width Not Applicable Collar Material Grade 2024 Keyway Depth Not Applicable Thread Direction Not Applicable Center to Lever Top Not Applicable Collar Construction 2-Piece Screw Material Alloy Steel