I’ve done two double braid splices in separate lengths of 8mm BeeLine and tested one to 660 lbs. I did three, no-load to full-load (660 lbs) cycles and a long hold on the last full load. It didn’t budge a fraction of a millimeter.

The nice thing about the double braid splice in BeeLine is that the core is fully protected by the cover and it just looks so neat and nice. There's no 'sleeving' or dipping required and you gain strength provide by the cover as an integral part of the splice. I found in the pull tests I did on BeeLine that a simple tucked-tail splice in the cover alone, i.e. just the cover, the core had been completely removed, the tucked splice held as well or better than the locked brumel in the core.

Then I noticed something interesting in Sherrill Tree’s newest catalog – they show two pics of eye-to-eye split-tails and in one of the pics there’s an unmistakable double braid splice in 10 mm BeeLine. Also interesting, is the 8mm BeeLine eye-to-eye is Brumel lock splice instead of the double braid splice used on the 10 mm.

I made one split tail with a double braid splice on one end and a locked Brumel on the other. Just as soon as I can get a colleague at school to fire up the tensile machine, we’re gonna pull test the Brumel against the double braid. If the double braid doesn’t win, I’ll be very surprised. BTW, I have been climbing on that particular split-tail ever since I tested one to 660 lbs.

FWIW, 660 lbs is all the force I can measure with my 330 lb scale at home – I do a 2:1 using the pulley on my 4000 pound cable come-a-long.

Interesting stuff, Ron. A quick comment and a question, too.




The comment: What you're seeing in the catalog is as it should be. Yale recommends the exposed eye for the 8mm Beeline and a standard double braid splice for the 10mm stuff.

The question: When you're doing the standard double braid splice in the 8mm stuff, how long are the cover and core tails? Are you sticking with the same measurements as polyester would call for, or are you lengthening things a bit.

I can't wait to hear what the break test reveals.

love
nick

I did the polyester measurements - here's my rationale: First, for the purpose of a split tail, it is not necessary to maximize the strength of the splice. Bee Line is rated at 8000 lbs - I certainly don't need 8000 lbs for a split tail. Even if the splice provided 5000 lbs, or 63% of Bee line's strength, that's way more than most 8mm cordage. The earlier pull tests I did on 8mm locked brumel splices indicated an initial failure at about 5000 lbs. These were the 'standard' brumel splices with a 6 - 7 inch tucked tail. Plus in the common closed split tail, there are two strands and hence two splices sharing the climber's weight.

I also found that a tucked tail using the cover only, was about as strong and secure as the locked brumel in the core. Hence the cover can provide surprisingly high strength. However, as you know, in a locked brumel splice, the core carries 100% of the load and the cover contributes nothing. But, in a double braid splice, again as you well know, the cover is tucked into the core, and the core is tucked into the cover and both then tucked into the cover. This means that both the cover and core are sharing the load.

It is extremely interesting that in my pull tests, the locked brumel core held near 5000 lbs; the tucked tail cover only held right at 5000 lbs. This suggests that the cover plus the core in a balanced condition should support nearly 10,000 lbs which is 2,000 lbs more than 8mm Bee Line is rated for.

I said all that to say this: with all the tucking in a double braid splice, IF THE CORE AND COVER REMAIN ESSENTIALLY BALANCED, the double braid should be much stronger than a locked brumel, but only a pull test will reveal if this is true or not. Further, in the double braid splice the cover protects the core completely.

Since I don't have a way to attach the non-spliced end of a rope except with a knot on our tensile machine, I'll likely pull a double braid I2I and see where it fails.

Isn't this just what you would expect? Of any splice? That it should be as strong or stronger than the rope. Take a hollow-braid splice, for example. Without a locked Brummel to complicate the picture, the body of the splice has twice as many load-bearing fibers as plain rope, and even the tapered section has more fibers than the plain rope. That's why in a pull test the rope typically breaks right at the end of the bury but not in the body of the splice. Certainly the fat part of the splice, if you could test it by itself, would prove to be very much stronger than the rope.

I am very interested in your testing of the locked Brummel. Did you post that here earlier where I can read about it?