How to build the gear kit
- Type the name, pick the kit and the board size that fits your printer.
- Download the kit: one file per part, already with the right number of copies.
- Print flat, no supports. Gears look great in different colours.
- Snap pins into the board, push gears on, clip the crank into a gear's small hole – and turn!
- Print the activity sheets: predict, count the turns, find the rule.
Recommended print settings
| Setting | Value |
|---|---|
| Material | PLA or PETG |
| Layer height | 0.2 mm |
| Infill | 20% |
| Supports | None |
| Pins | Print as they come (lying down) – stronger springs |
| Name in two colours | Filament change at 4.0 mm (board) |
Frequently asked questions
Why do the gears always fit together?
All gears share the same tooth size (module 2) and come in 12, 24 and 36 teeth. The distance between any two of them is 24, 36, 48, 60 or 72 mm – all multiples of the 12 mm hole grid. So any two gears on neighbouring holes in a row (or on a 3-4-5 diagonal) mesh. Kids just snap and turn.
How do the pins work?
Push a pin down through a hole in the board until the bottom snaps under it, put a gear on, and push the gear over the top barb. The gear turns freely and cannot fall off. Pins print lying down so their springy halves last.
What are the double gear, tall pins and spacers for?
The double gear (36 with a 12 on top) lets kids build two-stage trains with a big speed-up (1 : 9). Its small gear sits one level higher, so the gear it drives goes on a tall pin with a spacer under it.
What is the difference between the kits?
Starter: board, two 12-tooth, two 24-tooth and one 36-tooth gear, five pins, a crank and two flags. Explorer adds double gears, more gears, tall pins and spacers for two-stage machines.
What age is it for?
About 7 to 14 with an adult for the first build. Not for children under 3 – the pins are small parts.
How should I print it?
PLA or PETG, 0.2 mm layers, 20% infill, no supports. Print gears in bright colours (one colour per size helps kids talk about them). For the name on the board in a second colour, change filament at 4.0 mm.
Ages 7+ with an adult. Not suitable for children under 3 (small parts).