Shaft Collar System of Measurement Inch Bore Type Round Bore Diameter 4 in Bore Thread Size Not Applicable Collar Outside Diameter 5 3/4 in Inside Height to Flat Not Applicable Clearance Diameter 6.08 in Collar Width 1 3/8 in Collar Material Carbon Steel Keyway Width Not Applicable Collar Material Grade 1215 Keyway Depth Not Applicable Thread Direction Not Applicable Center to Lever Top Not Applicable Collar Construction 2-Piece Screw Material Alloy Steel