Slim Cord Lock / Stop - Shoe Lace Tensioner

Tame slack and tighten up with this ultra-slim cord lock featuring a fully 3D printed internal spring—no hardware, no fuss, just clean, printable tension. Whether you're cinching elastic laces, drawstrings, or DIY gear loops, it delivers secure hold in a compact, low-profile form.

Do you have shoes with faux elastic laces that can't easily be tightened? This is a flat lock / stop / tensioner that was designed to solve this problem.

Although it was intended to be attached to shoes, it also works well with round elastic or paracord. Use it wherever it helps to have a lock that is flat (as opposed to a more traditional lock, like this one, that is not flat). 

This model is 100% 3D printed. No hardware is required. It prints in place without supports. 

The hole is about 6.8 mm in diameter. It should easily accommodate 2 standard round shoe laces, or two pieces of Type III paracord. 

Dimensions:

• Thickness - 5.1mm
• Width - 23.97 mm
• Length - 45.302 mm

When printing, the model includes a bridge, which your slicer may warn you about (a “floating cantilever”). The bridge should print with no problem on any well-calibrated printer. But the round hole does sometimes come out a little rough. Pinch the model closed and make a couple of turns with your deburring tool. This should clean them up easily and not impact usability.  

Instructions

• Pull the excess slack out of your elastic shoe laces, pulling it toward the front of your shoe. 
• Pinch the lace lock closed, and insert the excess slack through the hole. 
• Tuck the lace lock under the laces. Also tuck the extra slack underneath.

As noted, this model includes a 3D printed spring, which is the key to making the cord lock function. As expected with springs, it needs to compress and bounce back without permanently deforming. PETG is fairly well suited for this (along with some other materials). But PLA is not well suited for this. I strongly recommend that you avoid PLA. The model was designed with PETG in mind.