Shaft Collar System of Measurement Metric Bore Type Round Bore Diameter 23 mm Bore Thread Size Not Applicable Collar Outside Diameter 45 mm Inside Height to Flat Not Applicable Clearance Diameter 52.1 mm Collar Width 15 mm Collar Material Stainless Steel Keyway Width Not Applicable Collar Material Grade 303 Keyway Depth Not Applicable Thread Direction Not Applicable Center to Lever Top Not Applicable Collar Construction 1-Piece Screw Material Stainless Steel