Ground Machined Worm Bore Diameter 6 mm Bore Diameter Tolerance +/- 0.1 mm Bore Type Plain Face Width 18 mm Finish Black Oxide Gear Shape W2 Material Carbon Steel Maximum Teeth Hardness 194 HB Metric Module Pitch 0.8 Number of Set Screws 1 Number of Starts 1 Outside Diameter 15.6 mm Overall Length 30 mm Pitch Diameter 14 mm