Trojan Horse Box — rolling, openable treasure horse

The Wooden Horse of Troy, reimagined as a little rolling treasure box.

Pull it along on four spoked wooden wheels, then swing open the hinged door in its back to reveal a hidden compartment inside the belly. Pure Odyssey / Iliad lore: the deception IS the gift.

READ THIS FIRST — THE BOX IS VERY SMALL. The horse is 76 x 40 x 90 mm and the hidden compartment inside it is only 31 x 15 x 13 mm (about 6 cm3 — roughly two sugar cubes). That fits a ring, a folded note, a SIM or memory card, a milk tooth, a couple of dice, a few pills. It is NOT a storage box — no phone, no keys, no earbuds case. Print it because it is a charming rolling toy with a secret. Want it bigger? Scale the whole model up in your slicer: 150 % gives a 47 x 23 x 20 mm cavity.

• Rolls: 4 spoked wheels on 2 axles that actually spin.

• Opens: a long door on a snap-pin hinge — no glue, no loose pin.

• Hides: a small rectangular compartment along the belly.

Nine Pieces, No Hardware, No Glue

• body x1 — horse, cavity, plank board, hinge knuckles

• door x1 — long door, same plank pattern as the skin

• wheel x4 — grooved log-style wheel, snaps on and spins

• axle x2 — thin rod with a split-collet snap bead at each end

• pin x1 — hinge pin; crush ribs grip the horse, never the door

• pin_coupon / axle_coupon — optional 1-2 minute fit-test slugs

PRINT SETTINGS PLA or PETG, 0.2 mm layers; wood-fill PLA sells the look. Body: upright on the plank board, mane up; light support under the chin only. Door: flat inner face down. Wheels: grooved face up. Axle and pin: print LYING FLAT so the layers run along the length — upright they shear along a layer line. Drop the axle in as exported and do not roll it about its own axis: the collet slot must come out vertical, nothing bridging over air.

ASSEMBLY (the gallery pictures follow these steps)

1. Slide an axle through the small hole in the base hub so it sticks out both sides. Push a wheel onto each end with the raised hub boss facing OUTWARD, away from the horse — the snap groove is inside that boss, so a backwards wheel physically cannot seat. It slides freely, then the split tip closes over the last couple of millimetres and the bead clicks into the groove. The wheel spins freely afterwards and will not pull off. Repeat for axle 2.

2. Hold the door against the opening so its knuckles mesh between the body's.

3. Feed the hinge pin in from the RUMP end, plain end first. It slides freely for about 37 mm, then the ribbed band turns it into a firm thumb push — the four ribs crushing in. Push until the end sinks just below the surface. The ribs grip the horse, never the door, so the door hinges freely.

4. Swing the door up, hide your (small!) treasure, let it drop shut, and roll the horse up to the gates of Troy.

IF SOMETHING DOESN'T FIT Wheel won't go on: print the axle coupon (1 min) and test that first; if it jams too, drop bead_r to 0.71 in the .scad and re-export. Wheel works loose: raise bead_r to 0.76 — don't glue it, it has to spin. Pin too tight: print the pin coupon (2 min); if even that won't start, drop rib_crest_r to 0.93. Pin works loose: one dot of CA glue on a single rib locks it and the door still turns. To remove the pin, push it out with a 4 mm rod from the muzzle end.

The .scad source is included — every clearance is a named parameter at the top.