3D Printable Gear Generator — Spur, Helical & Herringbone STL
Generate true involute spur, helical and herringbone gears with bore, keyway, hub and a meshing partner as STL · free, no signup
See 3D Printable Gear Generator — Spur, Helical & Herringbone STL in action
Free 3D Printable Gear Generator (Spur, Helical, Herringbone)
Printing a working gear needs a real involute tooth form, not an approximation. This generator builds the standard involute profile with the 1.25 module dedendum for any module, tooth count and pressure angle, then extrudes it as a spur gear, a twisted helical gear or a herringbone double-helix gear, optionally with a bore, keyway cut to DIN 6885 and a raised hub.
Add a mating gear and the tool places it at the right centre distance with the tooth phase set so the teeth mesh, showing ratio, centre distance and contact ratio. Backlash is adjustable for FDM or resin. Download one STL with both gears or a print layout, all processed in your browser.
Key features
True involute teeth
Standard 20°, 14.5° or 25° pressure angle.
Helical & herringbone
Twist angle up to 45°, double helix without axial thrust.
Bore, keyway & hub
DIN 6885 keyway and optional hub.
Mating gear
Meshed at the right centre distance with correct phase.
How to use it
- Set module, tooth count and thickness.
- Choose spur, helical or herringbone.
- Add bore, keyway, hub and a mating gear if needed.
- Download the STL.
Worked example
Example
Module 2 with 20 teeth has a pitch diameter of 40 mm and an outside diameter of 44 mm. Meshed with a 40-tooth gear the centre distance is 60 mm and the ratio is 2:1.
Who uses this tool
Robotics hobbyists
Custom gear trains.
Mechanical students
Study gear geometry.
Repair makers
Replace broken plastic gears.
Designers
Prototype gearboxes.
Tips for the best results
- Use at least 17 teeth at 20°.
- Print gears flat with 4+ perimeters.
- Helical gears must be paired with opposite hands.
- Add 0.1–0.2 mm backlash on FDM.
Common mistakes to avoid
- Meshing gears of different modules.
- Printing too fine a module for the nozzle.
- Forgetting that a single helix creates axial thrust.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
Do the gears mesh when printed side by side?
Choose the meshed layout to see them assembled.
Which hand is the helix?
Gear one is right-handed, the mate is left-handed.
What is the maximum number of teeth?
150.
Can I use metric modules only?
Yes, module is in millimetres.