July 15, 2026
Description
An extending Nuremberg-scissor (lazy-tongs) grabber-reacher themed as a
snapping dragon. It has ONE moving mechanism and a single degree of freedom:
squeeze the tail handle and the shared scissor angle shrinks, so the **neck
telescopes forward** (~135 mm collapsed → ~213 mm extended) and the **head
snaps shut** at the same time. Reach and bite are the same motion — spread the
tails to collapse and re-open the mouth.
Snap-pin assembled build (no glue, no supports): two rails of scissor links
offset by one layer, pinned at every crossing with printed snap-rivets. Fully
parametric in OpenSCAD (reach, jaw close angle, bar/pin sizes).
23 printed parts — 10 links + 13 snap-pins, across 7 STLs.
Print: everything flat, no supports. Pins print standing (flange down, barb
up); PETG recommended for the pins, PLA fine for the rest. Print one
pin + one link as a fit coupon first.
Assembly
Step 1 — belly rail. Lay handle → 3 links → upper jaw in scissor order.
Step 2 — spine rail. Lay the spiked spine rail over it, offset one layer.
Step 3 — crossing pins (x5). Pin each scissor "X" through the centre holes.
Step 4 — side-joint pins (x8). Pin the cell boundaries at the end holes.
Squeeze to reach + bite; spread to collapse + gape.
License:
Creative Commons — Attribution — Noncommercial
Miloslav Brožek
