Shaft Collar System of Measurement Inch Bore Type Round Bore Diameter 1/4 in Bore Thread Size Not Applicable Collar Outside Diameter 5/8 in Inside Height to Flat Not Applicable Clearance Diameter 0.77 in Collar Width 9/32 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