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Source: https://outdoors.stackexchange.com/q/10927
License name: CC BY-SA 3.0
License URL: https://creativecommons.org/licenses/by-sa/3.0/

<p>I have recently come into possession of many thousands of feet of paracord, more than any practical use would dictate. So this started me down the addictive path that is weaving and forming it into various more practical or at least decorative uses. One of the extremely easy knitting styles using a spool loom allows for some pretty elaborate rope design, and also allows for compact bundling of cordage into ropes that unspool into much longer cord lengths. Since this is ultimately still one strand just doubled back x times per pin in the loom, I would assume it gains no strength in this process, and by nature of all the additional bend radii I would further assume that it actually looses some strength in this process...</p>

<p>So what I would like to know is there any definable equation / references by which one can calculate the relative strength of a rope constructed of single cords in relation to the knit?</p>

<p>I am not looking to make climbing rope or push its limits, I never really see this being used as anything more than novelty items like leashes, gear holding, bracelets, and gun slings. I am just curious what the deduction is from the 550# relative strength of the cord to start with and how much it decreases with a 2 pin knit vs a 3 pin, 5, etc... Just so I would have some frame of reference if any of it ever had to be load bearing.</p>

<p><strong>Errata:</strong>
An example of the rope in question, this is a three plat knit using single cord over three pins in a spool loom. It produces a rope diameter of about 1" and compacts the cord about 4.5"(ish) per link, so 50' of <em>rope</em> is actually a manageable 200+ length of cord. <a href="https://i.stack.imgur.com/20Qst.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/20Qst.jpg" alt="enter image description here"></a><a href="https://i.stack.imgur.com/xRr4i.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/xRr4i.jpg" alt="enter image description here"></a></p>

<p>Original milspec 550 cord, I looped some over a limb, supported my body weight (190#) and only a few inches off the ground, bounced as hard as I could in effort to test its breaking strength, it held with no obvious signs of damage.</p>

<p>So though I would never climb on a homemade rope as a first choice, it seems it would not be an issue if I <em>did</em> need to, it is somewhat stretchy, I got about a 2' stretch out of about 20 feet of rope before it seemed to hold me in a solid position.</p>

<p>Using that homemade loom and a Philips head screwdriver as a tool, I made about 25' in an evening, so practical way to store a decent length of cord...</p>