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Roller Chain Sprocket Diameter Calculator

Calculate sprocket diameters according to ASME B29.1. Enter chain pitch, number of teeth, and roller diameter to get pitch diameter, bottom diameter, caliper diameter, tolerances, and approximate outside diameter.

  • Dr = roller diameter
  • N = number of teeth
  • P = chain pitch
  • PD = pitch diameter
roller-chain-sprocket-diameter-calculator

Pitch diameter of sprocket = P / sin (180° / N)

Bottom diameter of sprocket = PD − Dr

Caliper diameter (even teeth) = bottom diameter

Caliper diameter (odd teeth) = PD × cos (90° / N) − Dr

Tolerances on caliper diameter of sprockets:

  • Plus tolerance = 0.000
  • Commercial minus tolerance = 0.002 × P × √N + 0.006 in
  • Precision minus tolerance = 0.001 × P × √N + 0.003 in

Approximate outside diameter = P × (0.6 + cot (180° / N))

Maximum hub and groove diameter (MHD) = P × (cot (180° / N) − 1) − 0.030 in

Roller Chain Sprocket Diameter Calculator:

INPUT PARAMETERS
Chain Pitch [P] in
Number of Teeth [N]  
Roller Diameter [Dr] in

Note: Use dot "." as decimal separator.

 

RESULTS
Pitch diameter of sprocket in
Bottom diameter of sprocket in
Caliper diameter in
Caliper diameter plus tolerance in
Caliper diameter commercial minus tolerance in
Caliper diameter precision minus tolerance in
Approx. outside diameter of turned sprocket in
Max. hub and groove diameter (MHD) of sprockets in

Supplements:

Reference:

  • ASME B29.1-2011 - Precision Power Transmission Roller Chains, Attachments, and Sprockets

About the Roller Chain Sprocket Diameter Calculator

This calculator follows ASME B29.1 to compute sprocket pitch diameter, bottom diameter, caliper diameter and tolerances from the inputs.