SSN type gears come with M4 grub screws fitted. SSN10/10B and SSN10/12B are hobbed type pinions with cutter runout after the 5 mm gear face width. Steel Metric Spur Gears - Narrow Face. Steel EN8 (080M40/080M46) or equivalent 20° pressure angle DIN Standard - DIN 867, DIN 3962, DIN 3963, Grade / Quality 9 or equivalent Standard tolerance, unless otherwise stated ±0.25mm