Low-poly mountain key holder with trolley coin keyrings

A key holder for two sets of car keys, where each keyring is also a shopping trolley coin, so you always have one on you. The dock is a faceted low-poly mountain range in two pieces, one per keyring, printed in two different silk colours. Ours is screwed into the back of a deep box frame.

The parts

• Fob: a tough keyring with a C-clip head that holds the coin. Print one per set of keys. It's strong enough to live in a back jeans pocket.

• Coins: 23.5 mm across and 2.2 mm thick, trolley coin size. There's a blank one, plus the A and D coins we use with the letters engraved on both faces. Use the blank as it is, or add your own letter or initial in your slicer or CAD.

• Docks: the left and right mountain pieces. Each has a socket shaped round the fob head: lift the fob a few mm, drop it down the chute and it settles into the cradle, held out from the wall by a lip. Nothing to push or clip. Lift it out the same way.

Mounting

• One screw per piece, hidden behind it. Each piece has a J-shaped keyhole slot: drop it onto the screw head, slide it sideways into the short leg and it sits in the corner, so an upward knock won't lift it off.

• The left piece has a tongue that hooks into the right piece, so the two sit together like one part. Hang the left one first.

• Sticky tape on the back is optional if you want extra stability.

Print settings

• Printer: Elegoo Centauri Carbon 2, 0.4 mm nozzle

• Layer height: 0.2 mm

• Supports: none. Docks print back down, fobs and coins flat

• Material: I used silk PLA for the docks (green-red and yellow-purple dual colour) and translucent orange PETG for the fobs and coins. Use PETG or something similarly tough for the fobs, since they flex and get sat on.

• Filament: about 115 g for the two docks, about 10 g for two fobs and coins

• Time: about 5 hours for everything