BOSTON GEAR ND20B Gear, Spur, 12 Pitch. More details: Spur Gear, 12 Pitch, Pitch Dia 1.667 In, Face Width 0.750 In, Number of Teeth 20, Bore Dia 0.625 In, Outside Dia 1.834 In, Overall Length 1.250 In, Hub Dia 1.31 In, Hub Projection 0.50 In, Pressure Angle 14 1/2 Deg, Keyway None, Setscrew Not Included, Steel Material