Free · no account · STL, STEP, OBJ

Spur gear generator

Type the tooth count, module and bore. The generator builds an involute spur gear in your browser and exports STL for printing or STEP for your CAD package.

Try one:

Builds in your browser. The CAD engine downloads once (about 60 MB), then every part is local.

What to put in the prompt

  • Give the tooth count and either the module or the outer diameter. Module 1 to 3 prints well on FDM.
  • Give the bore diameter. For a motor shaft add the flat: a 5mm D-shaft bore.
  • Give the face width (thickness). 6 to 10mm is typical for printed gears.
  • Ask for a hub if the gear is thin: a 14mm hub, 6mm tall, with an M3 set screw hole.
  • For two gears that mesh, keep the same module and generate each one as its own prompt.

More on prompts: writing effective prompts.

Made with this generator

Real builds from the gallery. Open one to see the six-view render and the exact prompt, then build it or change a size.

20-tooth spur gear: isometric view of the generated model

20-tooth spur gear

Create one solid spur gear with exactly 20 teeth, outside diameter 50 mm, thickness 10 mm, a 5 mm through bore, and a flat bottom. Use an involute profile with 20 degree pressure angle. The outside diameter is the tooth-tip diameter, not the pitch diameter. Keep it a single watertight printable solid.

Forge (B-rep)QC 10/10

Browse the full model gallery

Frequently asked questions

What gear sizes can it make?

Any tooth count from about 8 up, and any module. Printed teeth under module 1 get fragile, so for FDM printing stay at module 1 or above.

Will two generated gears mesh?

Yes, if they share the same module and pressure angle (the default is 20 degrees). Centre distance is (teeth A + teeth B) x module / 2.

Can I export the gear as STEP?

Yes. The model is built on an OpenCascade kernel, so STEP export keeps the exact involute curves. STL and OBJ are also available.

Can it do bevel, helical or worm gears?

Spur gears are the reliable case. Helical and bevel gears are built as simplified solids and should be checked before printing.

Guides for this part

CAD tolerances for printed parts

Read the guide

Writing effective prompts

Read the guide

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