Shaft Collar System of Measurement Inch Bore Type Round Bore Diameter 1/8 in Bore Thread Size Not Applicable Collar Outside Diameter 1/2 in Inside Height to Flat Not Applicable Clearance Diameter 0.62 in Collar Width 1/4 in Collar Material Carbon Steel Keyway Width Not Applicable Collar Material Grade 1045 Keyway Depth Not Applicable Thread Direction Not Applicable Center to Lever Top Not Applicable Collar Construction 2-Piece Collar Material Finish Black Oxide