Shaft Collar System of Measurement Inch Bore Type Round Bore Diameter 1/8 in Bore Thread Size Not Applicable Collar Outside Diameter 3/8 in Inside Height to Flat Not Applicable Clearance Diameter 0.38 in Collar Width 1/4 in Collar Material Carbon Steel Keyway Width Not Applicable Collar Material Grade 1211 Keyway Depth Not Applicable Thread Direction Not Applicable Center to Lever Top Not Applicable Collar Construction 1-Piece Screw Material Carbon Steel