Step Up Adapter Bore Diameter 1/2 in Bore Depth 1 1/4 in Adapter Outside Diameter 1 1/4 in Shaft Length 1 1/4 in Shaft Diameter 3/4 in Overall Length 2 3/4 in Adapter Type Step Up Screw Thread Size 8 In.-32 Adapter Material Steel Adapter Material Finish Black Oxide Adapter Material Grade ASTM A108 Bore Tolerance +0.003/-0.000 Screw Length 1/2 in Screw Material Steel Screw Material Grade ASTM A574 Shaft Tolerance -0.000/-0.003 in System of Measurement Inch