Ground Helical Gear Bore Diameter 12 mm Bore Diameter Tolerance H7 Face Width 16 mm Finish Black Oxide Gear Shape S1 Gear Type Helical Hub Diameter 30 mm Hub Projection 13 mm Material Alloy Steel Maximum Teeth Hardness 60 HRC Metric Module Pitch 2 Minimum Teeth Hardness 50 HRC Number of Teeth 18 Outside Diameter 40 mm Overall Length 29 mm