3D printed gear generator
Generate a meshing gear train (involute gears at correct centre distances)
Lay out a meshing spur-gear train by tooth count and module: centre distances and the overall ratio are derived for you, and every gear carries the printing backlash a textbook mesh leaves out. Download a print-ready STL or 3MF with each gear as its own body.
How the 3D printed gear generator works
What you can adjust
- Teeth per gear (in mesh order) — 4–200
- Module
- Pressure ∠ — 10–30
- Thickness
- Helix ∠ — 0–45
- Bore Ø
- Backlash — 0–1 mm
- Keep teeth apart for printing
Spur gear size chart
Pitch diameter / tip diameter for standard spur gears: pitch Ø = module × teeth, tip Ø = module × (teeth + 2). Two gears mesh when they share a module; their centres sit (pitch Ø₁ + pitch Ø₂) ÷ 2 apart, and the generator adds the printing backlash.
| Teeth | Module 1 | Module 1.5 | Module 2 | Module 3 |
|---|---|---|---|---|
| 10 | 10 / 12 mm | 15 / 18 mm | 20 / 24 mm | 30 / 36 mm |
| 12 | 12 / 14 mm | 18 / 21 mm | 24 / 28 mm | 36 / 42 mm |
| 15 | 15 / 17 mm | 22.5 / 25.5 mm | 30 / 34 mm | 45 / 51 mm |
| 16 | 16 / 18 mm | 24 / 27 mm | 32 / 36 mm | 48 / 54 mm |
| 20 | 20 / 22 mm | 30 / 33 mm | 40 / 44 mm | 60 / 66 mm |
| 24 | 24 / 26 mm | 36 / 39 mm | 48 / 52 mm | 72 / 78 mm |
| 30 | 30 / 32 mm | 45 / 48 mm | 60 / 64 mm | 90 / 96 mm |
| 36 | 36 / 38 mm | 54 / 57 mm | 72 / 76 mm | 108 / 114 mm |
| 40 | 40 / 42 mm | 60 / 63 mm | 80 / 84 mm | 120 / 126 mm |
| 48 | 48 / 50 mm | 72 / 75 mm | 96 / 100 mm | 144 / 150 mm |
| 60 | 60 / 62 mm | 90 / 93 mm | 120 / 124 mm | 180 / 186 mm |
Printing gears that mesh
- One module for every gear. Module is the tooth size, and every gear in the train shares it. Gears with different-sized teeth do not mesh.
- The ratio is the teeth. Ratio is the driven gear’s teeth over the driver’s; Centres gives the distance between the shafts. The generator works both out as you go.
- The backlash is already in. A textbook mesh has no play and binds as soon as it is printed. Backlash adds the play a printed train needs.
- 20° is the standard. A Pressure ∠ of 20° is the standard angle; 25° lets a small pinion avoid undercutting the root of its teeth.
Gear questions
How do you calculate a gear ratio?
The driven gear’s teeth divided by the driver’s. With 12 and 24 teeth the ratio is 2:1: the small gear turns twice for every turn of the large one.
What is a gear module?
The pitch diameter per tooth, in millimetres. A module 2 gear with 20 teeth has a 40 mm pitch diameter. Gears with the same module mesh.
How far apart do two gears go?
Half the sum of their pitch diameters. 12 and 24 teeth at module 2 sit 36 mm apart.