STLGears
Free 3D gear generator with eight gear types and no account needed
Opens stlgears.com
About STLGears
STLGears is a free gear site run by a developer named Juan and supported by Ko-fi donations. It keeps things simple: open the 3D generator, choose a gear type, fill in the numbers and download an STL ready for your slicer, with no signup.
Eight gear types are available, ranging from plain spur gears to bevel gears, double helical gears and internal ring gears, which is enough to build a planetary gearbox. A separate 2D generator exports DXF files for laser cutting, and STEP export for CAD users is listed as coming soon. The site also has a theory section that explains how gears work, which helps if terms like module and pressure angle are new to you.
Supporter comments on the homepage come from teachers, students and hobbyists fixing toys and appliances, which sums up who it is for. It is a good first stop for anyone who needs a gear quickly.
What you can make
- Spur gears
- Bevel gears
- Double helical gears
- Internal ring gears
How to use it
- Open the 3D gear generator
- Pick a gear type
- Enter teeth, module and dimensions
- Download the STL
Good
- Free with no account
- Eight gear types including bevel and ring gears
- Built-in gear theory pages
Not so good
- STEP export not available yet
- No gear train simulation
What you'll need to print it
Materials and parts that give the best results with STLGears.
PETG for functional and outdoor prints
PETG handles heat, sunlight and repeated flexing better than PLA, so Gridfinity bins in a hot garage or signs mounted outdoors keep their shape.
- Bambu Lab PETG BasicUpgraded formula that Bambu says matches PLA Basic for strength while staying impact-tough; low price per spool in multi-roll bundles.
- Polymaker PETGHigh-flow replacement for PolyLite PETG: strong, low-odour and quick to print.
- Overture High Speed PETGGood-value PETG in a large colour range for functional parts in bulk.
M3 heat-set inserts and installation tips
Brass heat-set inserts give printed parts real metal threads that survive repeated screwing, and a dedicated insertion tip keeps each insert straight and flush.
- ruthex M3 threaded inserts RX-M3x5.7 (100 pcs)Brass inserts made for 3D-printed plastic, with matching ruthex soldering-tip sets.
- CNC Kitchen Heat Set Insert M3 x 5.7 (100 pcs)Double-knurled, lead-free brass; CNC Kitchen also sells an installation tip set for T18/900M irons.
- Bambu Lab Heat-Stake Nut Tool Tip SetInsertion tips with an optional USB-C soldering-iron bundle; pairs with Bambu's M3 brass inserts.
M3 screw assortment
M3 is the default fastener size for printed enclosures, hinges and mounts; a sorted kit of lengths saves a hardware-store trip whenever a model calls for bolts.
- Bambu Lab Fastener KitMixed self-tapping and machine screws with nuts, matched to Maker's Supply projects.
- Hilitchi M3 socket head cap screw assortment kitClassic boxed M3 assortment with nuts and washers in many lengths.
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