Climbing Monkey — Rope Pull Climbing Toy

The classic rope-climbing toy: pull the two beads one after the other — down and slightly outward, like milking a cow — and the monkey ratchets up the cords toward the banana. Let go and he stays put. Slacken both cords (or pull both beads gently outward at once) and he slides back down.

No springs, no glue, no moving parts. Each paw has a 2.4 mm channel tilted 45 degrees from vertical. At rest the cord kinks sharply at the bore's two sharp exits — capstan friction locks the monkey in place. Pulling one bead straightens that cord, the body rocks about the other (still-locked) paw, and the freed paw is hoisted a step up. Alternate pulls = he climbs.

Three printed parts:

- monkey.stl — 86 x 97 x 15 mm relief figure, prints flat on its back

- banana.stl — 96 mm spreader bar with centre hang hole, prints flat

- bead.stl — print 2, 33 mm pull handles (above the choke gauge)

Watch it climb: https://www.youtube.com/watch?v=FRPiWxPS_d4

You supply: 2 x 1.2 m of 1.25 mm linen twine (butcher's twine; any 1 to 1.5 mm string works) plus 0.3 m to hang the banana.

Assembly (5 minutes): stiffen the twine ends with tape, knot a stopper on top of each banana tip hole, run each cord down through the paw channel on its own side (in the top-inner opening, out the bottom-outer), through a bead, stopper knot hidden in the counterbore. Hang the banana by a short cord through its centre hole.

Different string? The attached .scad is parametric — set channel_d to about 1.5 x cord diameter + 0.3 and rebuild. Slipperier string (nylon mason line) makes the slide-down easier; fuzzier twine grips harder.

Print: any PLA or PETG, 0.2 mm layers, 15 percent infill, no supports, everything flat on the bed. All three parts fit one plate.

Safety: beads are 33 mm diameter (above the 31.7 mm small-parts choke gauge), no small detachable parts. Cords are long — supervise small children, as with any string toy.