Saturday, February 1, 2014

A Stronger Way to Sew Webbing

Credit goes to 1950s research by the Air Force, trying to make a better parachute.

The secret is the overlap, which spreads the force.

In three trials, the webbing failed every time.

100%, 108%, 103% of manufacture breaking strength. Granted, this batch was probably above the stated minimum. Still, I consider this to be a perfectly reliable join. Another investigator (current) working with sewing machines uncovered the idea and got the same result; nearly 100% efficiency joins.

There are about 24 full stitches of doubled 40-pound test whipping twine (96 strands), giving a 62% stitching efficiency; probably more than were needed, and I would add even more to a project to insure durability. But you get the idea.

Do NOT use high strength thread (Dyneema, Spectra, Kevlar)--they will only weaken the project, lacking sufficient give.


2 comments:

  1. Thanks! Do you think that this applies to machine sewn pieces the same way?

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  2. Yes, a friend was working on that angle and go the same results. It is based on a 1956 USAF testing contract for parachute construction.

    WACD TR 56-313 PT II

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