4mm Shock / Bungy cord lock/Paracord lock

thingiverse

I needed a lock when I replaced plain cord with 4mm bungy cord on my waterski boot. The lock is handy when a temporary lock is needed when tightening down the bungy. It's for adjusting non essential things and probably will LET GO if a heavy load is applied. So don't go skimping on a Petzl ZigZag or whatever. Maybe handy for closing backpacks, sacks etc. If anyone wants to adjust the dimensions for different thickneses of cord I have included the Freecad files. Let me know if you get stuck. You need to print this flat to get the maximum longitudinal strength although it is a pain winkling out the support material. So I have also included a version of the casing which can be printed with no support and then the 2 parts cemented together. This is a bit beefier and if you are printing in a fragile material I'd go with this one. The 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 are fastidious - to allow for locking and unlocking. I would print with maximum infill for as much strength as possible. If you are using 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 and totally free.