Ground Machined Worm Bore Diameter 8 mm Bore Diameter Tolerance +/- 0.2 mm Bore Type Plain Face Width 25 mm Finish Black Oxide Gear Shape W2 Material Carbon Steel Maximum Teeth Hardness 194 HB Metric Module Pitch 1.25 Number of Set Screws 1 Number of Starts 2 Outside Diameter 23.5 mm Overall Length 37 mm Pitch Diameter 21 mm