simple thread test results

[raisins]

TLDR: put Speedy Stitcher coarse thread up against same size bonded polyester and the speedy stitcher coarse won 10 times straight in a breaking strength tug of war.

In case this helps anyone:

I am about to sew 1" tubular webbing lineman's loop onto a harness. For this work, I got a speedy stitcher that comes with coarse, waxed polyester thread. The thread looked "low tech" to me and I couldn't find much info on it, and I read all about bonded polyester thread. I did find on sailrite that the coarse speed stitcher thread was roughly 346 in size (350 tex). So, I ordered the same size bonded polyester (service thread brand, which is supposed to be a good brand).

As a simple test, I tied overhand loops on a bight on the end of 8" lengths of each thread type. I then joined the tag ends of both with an overhand bend with the tag ends a square knot to stop slippage.

I then slipped one of the end loops over a peg above my head and slipped a metal rod through the hanging end. I slowly pulled until one of the threads broke, with the assumption that the breaking thread is weaker. I could have used my fishing scale to approximate break strength, but I didn't care outside of which thread was stronger (I was going to use one or the other, the winner).

I did this 10 times, alternating which thread type was on top. I expected the thread to break at one of the knots, particularly my awkward bend in the middle joining them.

This was not the case. In all 10 trials, the bonded polyester thread broke in the middle of the strand. This is supposed to be around 50 lbs break strength. I guarantee I did not pull 50 lbs (but can't prove it without a scale, might do that next, I was surprised how easily it broke and would estimate it at 30 lbs or less). I got to where I could predict the break point. I then tied two loops on a single piece of speedy stitcher thread to finally break some of it. It broke mid-strand (again surprising), but it was significantly harder to break.

So, unless you go with a very thick thread or kevlar thread, I feel it will be difficult to improve on the stuff speedy stitcher sends you in the box!

As a previous test, I took a length of 1" tubular webbing and doubled the end to make a loop. I then did one row of lock stitches with the speedy stitcher coarse thread from side to side using 6 stitches. I then did another row behind it the same, for two rows. I put this loop over this same peg and hung from the tag end with my full body weight with clothing and shoes (~190 lbs). It did not budge at all. I was extremely impressed.

Hope that helps someone else.

-R

 

[Mike Nutto]

Did you cross stitch where you connected them ?

 

[Mike Nutto]

ok never mind , this was a lot to mentally take in at first , I think as a whole the stitch pattern is what holds it together , you would have to do the same test with each one stitched and then put on a machine to see which broke first ,This is interesting as the speedy stich thread doesn't seem like it would be super strong , but I think if you go on their web site they are actually a sail company that makes that tool and they have thread I do believe. I wonder if that thread is water proof

 

[raisins]

I didn't try stitching webbing with both. That would be a better test. I just put the two threads against each other in a "tug of war" or a "turkey wishbone challenge". The speedy stitcher thread won so many times, so easily, that I firmly believe it is stronger. And it wasn't a knot thing, the thread was failing mid-strand. Makes me question the orthodoxy that knots are the weakest link, but that is in rope.

When I sewed the webbing, I just did 2 rows of 6 lock stitches and finished with a square knot keeping it from unravelling.

 

[Mike Nutto]

You should show some pictures