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Gear Model For 3D Printer (knowhave)

Free browser tool for spur, rack, planetary, bevel and worm gear sets, exported as STL

Gear Model For 3D Printer (knowhave) is a free browser tool for makers who know gear basics and need a planetary, bevel or worm set. Free, with no account, paid tier or ads. Exports STL. Last checked 26 September 2026.

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Opens knowhave.main.jp

About this generator

Gear Model For 3D Printer is a free browser tool that turns a handful of gear numbers into STL files for spur, rack and pinion, planetary, bevel and worm gears. A Japanese developer built it around 2014 on the OpenJsCad library, so the gear shape and the STL are computed in your own browser. Icons along the top switch between the five gear pages, a sixth page links ten ready-made sample STLs, and every page also has a Japanese version.

Each page is a short form for tooth count, module or circular pitch, thickness, bore radius, pressure angle and clearance. Pitch diameter, tooth count and module are linked, so changing one recalculates the others. The spur page can twist the teeth or stack a second gear on top for a stepped gear. The planetary page lists six drive ratios once the ring tooth count equals the sun's plus twice the planet's. On the multi-part pages each part exports as its own STL.

The site has not been updated in years: the English labels contain typos, there is no help text and there is no backlash setting. It suits people who already know what a module is and want a free planetary, bevel or worm set without an account or CAD.

What you can make

Spur gears, straight or twisted
Stepped double gears
Racks with a matching pinion
Planetary gear sets
Bevel gear pairs
Worms with a mating gear

How to use Gear Model For 3D Printer

Open the site and click the icon for the gear type you need
Enter the tooth counts, module, thickness and bore radius
Click VIEW UPDATE and check the 3D preview
Pick one part under VIEW SELECT, then click CREATE STL and STL DOWNLOAD
Repeat for each part and slice the STL files

What you'll need to print it

Filament and parts that suit what you make with Gear Model For 3D Printer.

PETG

M3 heat-set inserts

M3 screws

Bambu Lab Fastener Kit Bambu Lab
Hilitchi M3 socket head cap screw assortment kit (affiliate link) Amazon

Also handy

Digital calipers

Filament dryers and dry boxes

SUNLU FilaDryer S4 (affiliate link) Amazon
Polymaker PolyDryer (affiliate link) Amazon

Some of these are affiliate links: we may earn a small commission, at no extra cost to you. More about that

Gear Model For 3D Printer pros

Covers spur, rack and pinion, planetary, bevel and worm gears on one site
The planetary page checks the tooth counts and shows the ratio for each drive setup
Free, no sign-up, and the STL is generated in your browser

Gear Model For 3D Printer cons

Unmaintained since about 2014, with typos in the English labels and no help text
No backlash setting (clearance only deepens the tooth roots), so fit between printed gears is up to you
The worm page pairs the worm with a plain straight-cut gear rather than a curved worm wheel