Shaft Collar System of Measurement Metric Bore Type Round Bore Diameter 55 mm Bore Thread Size Not Applicable Collar Outside Diameter 82 mm Inside Height to Flat Not Applicable Clearance Diameter 88.8 mm Collar Width 19 mm 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