Our 0.125" (1/8”) bore, 16 teeth pinion gear attaches directly to any 1/8” diameter gear motor or stepper motor output shaft. Or attach to our 1/8” diameter precision shafting. Simply slide them on and tighten the 10-32 set screw. This gear have a 20 degree pressure angle. Manufactured from hardened brass gear stock. The set screw requires a 3/32” Hex Key (sold separately).