Number of Teeth (Chordal Action)Nom. Pitch DiameterNom. Outer DiameterNom. Hub WidthAvailable Bore Sizes
inmminmminmmRound in1Square in Round mm2Square mm
16 (1.92%)5.11305.21322.0511 to 231.525 to 50440
18 (1.52%)5.71455.81482.0511 to 231.5, 2.525 to 50440, 60
21 (1.12%)6.71706.81722.0511 to 22, 31.5, 2.525 to 50440, 60
  1. Imperial key sizes on round bore sprockets are based on ANSI standard B17.1-1967 (R1989) and metric key sizes are based on DIN standard 6885.

  2. Tight fit round bores are available in 1-1/4, 1-3/16, 1-1/2, and 1-7/16 in.

  3. Available in 1/16 in increments

  4. Available in 5 mm increments