A clip for the 2.54 mm (0.1″) pin-header grid. Set the channel count and length, then export an STL. What is this & how do I print it? ↓
Female pin header connectors - the small black plastic housings (often called Dupont connectors, jumper wire housings, or crimp housings) that plug onto 2.54 mm (0.1″) male pin headers - are notoriously loose. There's no real latch holding them on. A light tug on the wires, vibration from a fan or motor, or just routing the cable the wrong way is enough for the connector to work partway off the pins, causing an intermittent or dead connection.
That's a common headache on 3D printers, robots, RC vehicles, drones, and any project that moves, vibrates, or gets handled. PinHeaderClip is a free, parametric, 3D-printable clip that solves it: a small bridge-shaped part with a fork-shaped foot at each end that snaps around the base of the male pin header, on either side of the female connector, pinning the whole housing down against the board so it can't lift, wiggle loose, or get pulled off by wire tension.
PETG is recommended over PLA. It's a little more flexible and layer-adhesive, which matters here - the fork tines need to flex slightly to snap over the pin header without cracking. PLA is more brittle and more likely to snap off a thin tine under that stress.
A 0.4 mm nozzle works fine for this part; a smaller 0.2-0.3 mm nozzle will give slightly crisper detail on the small fork and slot features if you have one on hand. The clip prints flat on its back with the forks facing up, so no supports are needed.
PinHeaderClip is open source. The parametric OpenSCAD model
(clipsingle.scad) and this configurator's source are on
GitHub.