Power transmission calculator

Chain Sprocket Generator

Create a laser-cuttable plate sprocket STEP for common ANSI roller chains, calculate its dimensions and chain speed, then order it from Fabworks.

Build a laser-cut plate sprocket

Select a roller chain, then set its tooth fit, bore, and plate thickness.

Set all
rpm

Generated dimensions

Pitch diameter
2.8794 in
Outside diameter
3.1356 in
Generated root diameter
2.5628 in
Roller seat radius
0.1583 in
Chain speed
225 ft/min
Plate material
Steel 1008
Plate thickness
0.187 inRecommended fit
Chain side clearance
0.0628 in per side

ANSI roller chain dimensions

Recommended plate thickness leaves side clearance inside the chain.

ANSI #40 selected
ChainPitchRoller diameterInside widthIdeal plate
ANSI #250.250 in · 6.35 mm 0.130 in · 3.302 mm 0.125 in · 3.175 mm 0.098 in · 2.5 mm
ANSI #350.375 in · 9.525 mm 0.200 in · 5.08 mm 0.188 in · 4.763 mm 0.118 in · 3 mm
ANSI #400.500 in · 12.7 mm 0.312 in · 7.925 mm 0.313 in · 7.938 mm 0.250 in · 6.35 mm
ANSI #410.500 in · 12.7 mm 0.306 in · 7.772 mm 0.250 in · 6.35 mm 0.188 in · 4.763 mm
ANSI #500.625 in · 15.875 mm 0.400 in · 10.16 mm 0.375 in · 9.525 mm 0.313 in · 7.938 mm
ANSI #600.750 in · 19.05 mm 0.469 in · 11.913 mm 0.500 in · 12.7 mm 0.375 in · 9.525 mm

Laser-cut profile preview

The B29.1 profile uses a roller seating curve, working curve, tangent flat, and topping curve. The dashed roller shows engagement at the pitch circle.

ASME B29.1 profile

Generate the manufacturing file

100% in-browser

OpenCascade builds and reopens the STEP entirely in your browser. No dimensions, settings, or geometry are uploaded.

Laser cut it at Fabworks

We will generate the STEP if needed, add it to a new quote, and open that quote in a new tab for material, finish, and quantity.

The STEP uses the ASME B29.1 theoretical tooth form and catalog outside-diameter truncation. Manufacturing tolerances, material, heat treatment, alignment, lubrication, and application loads still require engineering review.

Quick answer

How this sprocket calculator calculator works

A roller-chain sprocket pitch diameter is set by chain pitch and tooth count. Choose an ANSI chain size, tooth count, bore, and Fabworks plate thickness to preview a true chain-sprocket profile and generate a laser-cuttable STEP solid in the browser.

How to use the calculator

  1. 1Choose the ANSI roller-chain size so pitch and roller diameter match the chain.
  2. 2Enter tooth count, shaft speed, bore, material, and an available Fabworks plate thickness using the unit selector on each dimensional input.
  3. 3Use profile tuning only when you understand the clearance or tip-relief change being made.
  4. 4Generate the STEP file, inspect the preview and dimensions, then send the part into a Fabworks quote for manufacturing review.

Worked example

#40 chain, 18-tooth sprocket

Inputs
ANSI #40 chain with 0.500 in pitch, 0.312 in roller diameter, and 18 teeth.
Result
Pitch diameter ≈ 2.879 in; planning outside diameter ≈ 3.136 in; planning root diameter ≈ 2.567 in.

The generated tooth profile uses the selected chain geometry; bore, plate thickness, clearance, and tip relief remain editable manufacturing choices.

Common questions

What to know before using the result

Is this a timing-belt pulley profile?
No. It is a roller-chain sprocket profile with roller seats and working flanks. HTD and other synchronous-belt pulleys use different tooth geometry.
Is the STEP file generated in the browser?
Yes. The profile and uniform-thickness solid are generated locally in the page, so no CAD software or separate download tool is required.
Can a laser-cut plate sprocket be used at any load and speed?
No. Material, thickness, hub and keyway design, alignment, lubrication, wear, heat treatment, speed, and shock loading all affect suitability.

Formula

Dₚ = p ÷ sin(180° ÷ N)

Pitch diameter Dₚ is set by chain pitch p and tooth count N. The generated profile follows the ASME B29.1-2011 (R2022) theoretical tooth construction: roller seating curve, working curve, tangent flat, topping curve, and catalog outside-diameter truncation.

Engineering references

Assumptions and limits

  • Presets use nominal ANSI roller-chain pitch and roller diameter values covered by ASME B29.1.
  • The browser-generated STEP is a closed, uniform-thickness plate sprocket with a round bore.
  • Nominal fit uses the standard theoretical minimum seating curve; optional clearance and tip relief are deliberate deviations for prototype tuning.
  • Hubs, keyways, bore tolerances, material, heat treatment, and high-speed applications require an engineering review.
  • Chain speed assumes the sprocket rotates at the entered shaft speed without slip.
Educational estimate
Use this result for learning and early design exploration. Verify safety-critical or production decisions with the governing standard, material data, real tooling, and a qualified engineer.

Keep designing

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