From the Loftsmith community

5 mm shock cord jammer

Holds a 5 mm shock cord at the tension you set, so you can stop knotting and re-knotting it. Push the cord into the notched slot and the toothed edge bites down to keep it from creeping back. Change the cord size to match yours.

1 part · 8 g · 75 × 26 × 10 mm

Flat blue oval tab with a toothed slot at one end and a round recess at the other, with a cord running through
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No adjustable sizes

Ask for the sizes you want to tweak, e.g. “make the width adjustable”.

Change it in the Studio

Parts

  • jammer · PETG · Flat on its bottom face, knot pocket facing up

    No supports needed

Print settings

Layer height
0.2 mm
Walls
3
Infill
20% gyroid
Supports
None
Notes
Standard PETG profile. Use 3 walls so the slot teeth and prongs are mostly solid plastic.

Assembly

  1. Thread the end of the cord up through the round hole from underneath and tie a figure-8 or overhand knot, then pull it down into the pocket.
  2. Wrap the cord around the things you're holding, and bring it back up under the jammer at the slot end.
  3. Press the cord into the open end of the V-slot, pull the tail tight and up, and it wedges into the narrow end.
  4. To release: lift the tail and slide the cord back out of the open end.

Good to know

  • How well it grips depends on your cord. If it slips, set the 'Slot narrow end' slider lower; if it's too hard to pull in, set it higher. If your knot is bigger than 14 mm, raise the 'Knot size' slider.
  • In the Use it animation, the cord pieces touch each other and the slot teeth on purpose: the cord is one piece, and the teeth are meant to bite into it. That touching isn't a fault.
  • The strength figures are worked out, not tested. Try it at a hard pull before you trust it with anything important.
I printed this Remix

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