How to stitch dyneema

thinwater

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Remember, the stitching does not have to hold much; the contraction does that. Second, once the load comes on the fibers tighten up around the thread and it won't slip.

I just put a big knot on the tail of the thread and insert it into the hollow space in the throat of the splice; this hides the start. The finish can be clipped off flush and does not need to be secured.

You can hide the stiching completely by using matching thread and placing it alongside the braid. Invisible. But if you decide to pick out the splice to adjust length, you will wish you had used contrasting thread and made the stitches visible by placing them across the braid, on the surface. For this reason, I no longer worry about hiding the stitching and usually use black thread. Cosmetics matter less to me than function.
 

zoidberg

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I think it important to emphasize - just so everyone knows - that the purpose of the stitching is to hold the 'bury' in place when the eye-splice ( and its rope ) is unloaded and flogging/flexing loosely about.

Some will use a simple single set of 'square' stitches in a line; others will follow that up by rotating the rope/splice through 90 degrees and running a second line of 'square' stitches back to the origin. That could be thought 'belt and braces'.....

Thinwater and most others will know that, but it needs restating for some.
 

GHA

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why not do a brummel lock splice? Don't think many use stitching. Though from experience with dyneema in industry a normal bury splice is pretty much impossible to shake out......... but it might ...
Tapering the tail *is* important. Destruction testing dyneema is nowhere near as exciting as destruction testing steel wire rope ?

Some load testing data from an old site >
https://web.archive.org/web/20160715154948/http://www.bethandevans.com/load.htm
 

Neeves

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I am stitching 12 stand with a double bury, eyes at each end. The stitching is in the middle of the splice. I always have an overlap of the 2 buries, so cover and the 2 x 12 strand inside. The buries tend to feel flat - where the two buries lie, side by side and I simply stitch through the cover, randomly, and through both buries. I have about 50mm length of stitching and then reverse and stitch at 90 degrees through each bury, so a reverse of the first row for one side and then back again for the other side. I simply stitch tightly and close together. By the time I finish the stitching is tight and actually difficult to insert the needle. I use 2m of thread for each splice. I then cover the stitching with heat shrink, for rope (not electrical heat shrink - different animal). The thread is braided dyneema fishing line. When you stitch you could plan to stitch at a specific part of the 12 strand - but it is almost impossible to define where the stitch exits on the other side - so my stitching is random.

I developed our snubbers using retired climbing rope but when I felt I had what I wanted I bought new climbing rope. I knew it came with sewn eyes and specified slight longer sewing. When it arrived it had heat shrink covers - which gave me the idea to use the same practice for my own sewing. This is professional sewing.


IMG_9983.jpeg

IMG_9984.jpeg

I did get it wrong - this is 12mm rope and we found that it was not quite as 'elastic' as we wanted - we replaced it with 10mm rope, same sewn eyes, which has been fine. I noted that the sewing was through the diameter and have done the same with my buried splices.

There is no doubt professional sewing with a machine looks ..... better (than my amateur efforts).
Remember, the stitching does not have to hold much; the contraction does that. Second, once the load comes on the fibers tighten up around the thread and it won't slip.

I just put a big knot on the tail of the thread and insert it into the hollow space in the throat of the splice; this hides the start. The finish can be clipped off flush and does not need to be secured.

You can hide the stiching completely by using matching thread and placing it alongside the braid. Invisible. But if you decide to pick out the splice to adjust length, you will wish you had used contrasting thread and made the stitches visible by placing them across the braid, on the surface. For this reason, I no longer worry about hiding the stitching and usually use black thread. Cosmetics matter less to me than function.

But with black dyneema, which is very difficult to mark with a felt pen, use white thread :)

And on quality.

Needed to make two identical (that's the ambition) splices with eyes at both ends.

I measured my dyneema, all the same diameter from the same rope. I had enough for 3 x X70 overlap all of the same size. I made 3 splices the same way (well - obviously not :( ) and they resulted in 3 different lengths. The length of the eventual buries varied + or - 2cm for a 60cm bury. For my application it does not matter, the tensions are not high - but I don't consider it 'good enough'.

So why did I make 3, when I only needed 2. I thought I'd test one. They are all buries from both ends, no sewing

Jonathan.
 

lustyd

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why not do a brummel lock splice?
It's ultimately a bit less strong when compared to a bury. While the lock ensures no slippage it does put more pressure on a couple of small bits of the rope rather than spreading the load. It's also a bit less easy to do/remember.
 

thinwater

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why not do a brummel lock splice? ...

A Brummel is good, and I use them, but there are several reasons you might not.
  • Harder to adjust the total length just right.
  • More difficult when the second end is not accessible.
  • Pretty much impossible in loop and end-to-end splices.
  • Often you have the needle out because of coverings or seizings.
  • Aesthetics. Some people prefer one look over the other. Some enjoy the process of making a Brummel. A briefs vs. boxers kind of thing.
I'd say learn both methods.
 

thinwater

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I would also offer that double braid splices benifit from either siezing, or better, lock stitching. I've seen a lot of cover buries work loose. If you remove core lock stiching prevents slippage (although you need to milk the core into possition first).
 

GHA

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A Brummel is good, and I use them, but there are several reasons you might not.
  • Harder to adjust the total length just right.
  • More difficult when the second end is not accessible.
  • Pretty much impossible in loop and end-to-end splices.
  • Often you have the needle out because of coverings or seizings.
  • Aesthetics. Some people prefer one look over the other. Some enjoy the process of making a Brummel. A briefs vs. boxers kind of thing.
I'd say learn both methods.
Completely agree, learn anything & everything! ?
Though imho the above points aren't really a big deal, bit of practice you can get very close to a designed length when making eye/eye strops after loading. about 10% shrinking in the splice from memory.
Same for brummel when just one end of the rope is exposed, practice a few times & easy enough. IMHO brummel sits nicer after loading with no locking stitches to catch on anything.

Each to their own. ?
 

Neeves

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With a double bury, 100% through the outer sheath, tails just protruding both ends and an eye at each end I am 'losing' 25% of the length as a result of the sheath being bigger. This is after hand manipulation, kneading and tensioning by hand.

Jonathan
 
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