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Does sewing thread into nylon webbing destroy KN rating?


Original Post
Jon Hartmann · · Ojai, CA · Joined Feb 2009 · Points: 1,320

Simple question I think. I tied a piece of webbing with a water knot for my old cam. I decided to sew the tail ends down so that they wouldn't ever creep out. Do you think that putting this much stitching in there compromised the KN strength of the original webbing? I know they bar tack sew webbing all the time but I didn't know if it was with special tensile rated thread or if the sew pattern is what doesn't destroy the webbing. Any professional opinions?

Jon Hartmann · · Ojai, CA · Joined Feb 2009 · Points: 1,320

JonasMR · · Unknown Hometown · Joined Feb 2016 · Points: 6

I don't know the answer to your question, but am curious too.  What kind of thread did you use?

Jon Hartmann · · Ojai, CA · Joined Feb 2009 · Points: 1,320

Just normal sewing thread from my wife's sewing kit. Pretty standard stuff. 

Jon Hartmann · · Ojai, CA · Joined Feb 2009 · Points: 1,320

I was going to tape the ends with climbing tape but I thought I was being smart sewing it until I was done and thought about it some more. The fibers seem like they would just move out of the way when the needle goes through instead of cutting them but the stitch is so ...full... that I wonder if I just guillotined all the fibers under the stitching. 

JonasMR · · Unknown Hometown · Joined Feb 2016 · Points: 6

My guess would be that stitch design is used because one does cut some threads, but the new threads of the stitch take up the slack.  So, still guessing, nylon thread in a nylon sling would be cool but cotton/poly thread would weaken it overall.  But basically just bumping your thread for someone actually in manufacture/design to help us out here.

Jon Hartmann · · Ojai, CA · Joined Feb 2009 · Points: 1,320

I just checked. It is indeed cotton thread. 

Greg D · · Here · Joined Apr 2006 · Points: 867

Cotton kills.  Just don’t use those cams in the back country where they could get wet and hypothermic. 

Kirtis Courkamp · · Golden · Joined Mar 2011 · Points: 378

nylon webbing  strength about 22 kn cam strength 12 kn really bad fall force about 7 kn  I think you'll be ok 

curt86iroc · · Golden, CO · Joined Dec 2014 · Points: 61
Kirtis Courkamp wrote:

nylon webbing  strength about 22 kn cam strength 12 kn really bad fall force about 7 kn  I think you'll be ok 

Just a quick FYI.  The knot in the webbing will reduce its breaking strength by about 40%...

Gunkiemike · · Unknown Hometown · Joined Jul 2009 · Points: 2,785

You're fine; don't worry about it.

eli poss · · Durango, Co · Joined May 2014 · Points: 442

If I recall correctly, there is potential to damage the webbing, depending on what type of needle was used. They use a special needle that doesn't damage the webbing.

You're probably still fine and the webbing is probably still stronger than the cam but there's only one  way to find out for sure. Get the same webbing and tie one loop without the stitching and one loop with the stitching and pull them both to failure. There's a guy on this thread that'll do it for you. 

Gunkiemike · · Unknown Hometown · Joined Jul 2009 · Points: 2,785
eli poss wrote:

If I recall correctly, there is potential to damage the webbing, depending on what type of needle was used. They use a special needle that doesn't damage the webbing.

You're probably still fine and the webbing is probably still stronger than the cam but there's only one  way to find out for sure. Get the same webbing and tie one loop without the stitching and one loop with the stitching and pull them both to failure. There's a guy on this thread that'll do it for you. 

Unless you're buying the special "leather needles", you're using a ballpoint needle in your machine. These part the fibers rather than cut them. As I said, you're fine.

Larry S · · Easton, Pennsylvania · Joined May 2010 · Points: 840

I've done this too when a sling on a cam got messed up and needed a quick replacement.  It ended up on there for a few years.  I didn't use nearly that much stitching though. The water knot is for the load, the stitches are just there so the knot can't come loose. I'd say you're fine. I'd prefer a nylon or poly thread though.

Guideline #1: Don't be a jerk.

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