Does sewing thread into nylon webbing destroy KN rating?

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?

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

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

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. 

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.

I just checked. It is indeed cotton thread. 

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

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

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%...

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

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. 

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.

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.

to wake up an old thread over a year later that i just came across, for most parachute rigging and when i bartack slings, i use e thread. its pretty damn strong in itself. just do a search, you can pick it up cheaply pretty much anywhere.....

Beer knot is superior 

You can get cams reslung for $7-8 a piece. Do yourself a favor and have it done professionally.

I remember back in the 80's there was some data on sewing web.  What I remember is sewing the tails of the water know increased the strength a lot. look at old On Belay Magazine.

While I agree with Derek, if you are DIY sewing, use a round point needle. Chisel point will cut webbing fibers, round point will part-push webbing fibers aside.

I'm quite sure the knot weakens more than the stitching.

Note on this vid clip: 10mm Dynex – sewn – 60cm – rating 22kN part way down the page that the sling breaks at the pin, not the sewn part: https://www.blackdiamondequipment.com/en_US/experience-story?cid=qc-lab-ultimate-strength-gear-testing

Also this photo from the same page shows where slings broke in testing. Note the two knotted slings failed at the knot, and except perhaps for one, the sewn runners did not break where sewn.

Rick.Krause Krause wrote: I remember back in the 80's there was some data on sowing web.  What I remember is sowing the tails of the water know increased the strength a lot. look at old On Belay Magazine.

When you sow the webbing, do you need special fertilizer? What about the watering schedule? How much time is needed from germination to harvest?

Chris K wrote: Beer knot is superior 

It’s extremely hard to tie a beer knot in 5/8ths webbing, and the 5/8ths sits way cleaner in some cams, old c4 Camelot’s especially.