Spiral Miter Gear Bore Diameter 6 mm Bore Diameter Tolerance +/- 0.1 mm Bore Type Plain Face Width 6 mm Finish Black Oxide For Shaft Angle 90 Degrees Gear Shape B3 Hub Diameter 20 mm Hub Projection 8 mm Material Carbon Steel Material Grade S45C Maximum Teeth Hardness 60 HRC Metric Module Pitch 1 Minimum Teeth Hardness 50 HRC