alpaco.it Gear Generator
Meshing spur, helical or herringbone gears set by module and teeth, with shaft fittings
alpaco.it Gear Generator is a free browser tool for replacement gears and simple drive pairs for robots, toys and models. Free with no account; optional Buy Me a Coffee tips, and a Google sign-in only for saving setups. Exports STL, 3MF and SVG. Last checked .
Opens alpaco.it
What is alpaco.it Gear Generator?
alpaco.it Gear Generator is a free browser tool that turns a few numbers into a printable involute gear, with an optional matching pinion. You set the module, tooth count, face width, pressure angle and backlash, then pick straight spur teeth, angled helical teeth or a herringbone. A flat top view, a meshing view and a 3D preview follow your edits, and help icons explain the trickier settings.
To fit a shaft you can add a bore, a D-flat for motors such as N20 units, a rectangular keyway or a raised hub. Tick the pinion option and a second gear is cut to mesh with the first, with the helix turned the opposite way on helical pairs. The ZIP holds an STL per part, a 3MF with the parts laid out on the build plate, SVG drawings of the profile and a text sheet with print advice and, for pairs, the axle spacing and ratio.
It is one of 36 generators on alpaco.it, a hobby site run by one maker in Poland. No account is needed and the terms allow selling your prints. The gear tool went live on 29 August 2026 and had little outside feedback as of September 2026. It suits makers who need a replacement gear or a simple drive pair for a robot, toy or model.
What you can make
- Spur gears
- Helical gears
- Herringbone gears
- Gear and pinion pairs
- Gears with keyed or D-shaped bores
How to use alpaco.it Gear Generator
- Open the Gear Generator and pick a preset or keep the defaults
- Choose spur, helical or herringbone and set module, teeth and width
- Add a bore, D-flat, keyway or hub, and tick the pinion box if you need a pair
- Click Download STL + 3MF, then save the ZIP it builds
- Print the gears flat and mount the axles at the spacing in the notes
What you'll need to print it
Filament and parts that suit what you make with alpaco.it Gear Generator.
PETG
M3 heat-set inserts
M3 screws
Also handy
Digital calipers
Filament dryers and dry boxes
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alpaco.it Gear Generator pros
- True involute teeth, and the print notes give the exact axle spacing for a matching pair
- Shaft options cover a plain bore, a D-flat for motor shafts, a keyway and a hub
- Free without an account, and the terms allow commercial use of the files
alpaco.it Gear Generator cons
- Launched in August 2026, with no user reports on how its gears hold up as of September 2026
- Only spur, helical and herringbone styles: no racks, bevel, worm or internal gears
- Models are built on the owner's own machine, with no uptime promise
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