4mm Shock / Bungy cord lock/Paracord lock

thingiverse

I required a lock when I replaced plain cord with 4mm bungy cord on my waterski boot. The lock proved handy when a temporary lock was needed while tightening down the bungy. It's designed for adjusting non-essential things, but it may LET GO if a heavy load is applied. So don't skimp on a Petzl ZigZag or similar product. Maybe handy for closing backpacks, sacks, etc. If anyone wants to adjust the dimensions for different thicknesses of cord, I've included the Freecad files. Just let me know if you get stuck. To maximize longitudinal strength, print this flat. It's a bit of a pain wiggling out support material, so I've also included a version of the casing that can be printed without support and then cemented together in two parts. This design is three-part and assembly is really obvious. The cog wheel sits inside the casing, and the thumb button gets inserted into the cog wheel - with a drop of glue if you're fastidious - to allow for locking and unlocking. I recommend printing with maximum infill for as much strength as possible. If you're using it for paracord, print the 9.5mm cogwheel, as parachute cord is not as thick as the 4mm bungy. Thanks to Freecad - it's incredible software that's totally free.