A concern about the Arborist Splice

[RonReese]

Iím new to braided rope splicing, but I have done 6 eye splices in Velocity rope following Samson Ropeís instructions. They work and look good. After watching Brionís splicing video, I now know how to make them better ñ a special thanks to Brion for taking time to make a video on splicing.

Getting to my concern, I made my first eye splice in ArborMaster 1/2î rope. ArborMaster is a braided cover with a core of twisted strands. I watched Brion Tossís video where he spliced an eye in New Englandís Safety Blue rope. Safety Blue looks like it has the same or at least similar construction as ArborMaster.

To make a long story a little shorter, by the nature of the arborist splice, the core and the cover overlap inside the cover well down the rope away from the eye. Thatís what concerns me - the overlap. The overlap of the cover and core, inside the cover, seems to me, produces a weak spot in the rope. At the overlap, I presume part of the strength at the overlap is supposed to come from the overlapping core and cover strands and hence, presumably the overlapped strands have nearly the same strength as the non-spliced rope. At least thatís what weíve been told ñ a splice approaches the full strength of the rope.

But if the overlapped strands can slip at all, load is transferred to the cover. I suppose there is the Chinese finger trap action of the core at the overlap, but even with that if there is ìthinningî of the core due to a slightly insufficient overlap there will be a reduced cross sectional area and it seems like that would produce a significant reduction in strength.

Thoughts?????

Thanks,
Ron

[Brion Toss]

Hello,
Excellent question. On some ropes, like Sta-Set-X, all of the strength is in the core. An overlap splice in that rope would have some strength, but not enough; that's why the X splice is the way it is. But in arborist and similar ropes, most or all of the strength is in the cover, and the core is there to keep the rope round. The overlap is meant to maintain constant diameter, not to contribute to strength.
Note that some arborist rope, like Fly, has all the strength in the core, even though the construction looks the same as cover-strength ropes. So as with any splice, make absolutely sure you are doing the right splice, before you pick up your tools.
Fair leads,
Brion Toss

[RonReese]

Thanks, Brion. That's a relief. If the cover is the strength then my concern goes away.

Here's a link to three pics of the splice; you can't really tell much, except that its a splice.

Since I made the pics, I have stitched the base of the splice. I'm considering whipping it as well. I noticed your DVDs don't show a whipped or stitched splice, so I'm a litte foggy on what constitutes a good whip on this splice. Suggestions?

P.S.
How important and what is the purpose of stitching and whipping eye splices? Also, which is better, stitching or whipping?

Thanks,
Ron

Splice pics (three) - Some pics of Velocity splices as well (among other things):
http://www.combatcarry.com/vbulletin...ad.php?t=16495

[Brion Toss]

Hi again,
I mention elsewhere in the video that I much prefer stitching ó and invisibly stitching, at that ó to whipping. The purppose of both is to hold the splice together at low loads, when the "Chinese handcuff" effect is weakest. Whippings look emphatic, but they typically engage the interior of the rope minimally. This leaves the support largely to compression from the round turns. This seems less effective, as well as being vulnerable to chafe.
Because the cover is braided, stitching between surface yarns will always engage the layer underneath. So you can stitch invisibly, but still tie the core to the cover, with no chafe vulnerability. Plus I think it's more elegant.
Fair leads,
Brion Toss

[RonReese]

Thanks again, Brion. That's the way I see it as well.

I don't see any way to do a PM (private message), but I want to say this, so I'll take a bit of liberty to say it here:

I've been teaching at a community college for almost 20 years. I know good and bad "teachers" almost as soon as I see them in action. One of the things that good teachers do is break down complex problems to a logical sequence of less complicated steps. Another thing is they have insight to the "student's" perspective and knowledge base and work from that level. Good teachers have a way of gaining students' confidence and projecting the idea that "they" can do what their being taught. Probably most important of all is the hard-to-define talent of transferring knowledge. I believe this is one of the main things that separates excellent teachers from good teachers.

You exhibit all these things, and more. You clearly are a gifted instructor. I also enjoy those subtle humorous comments you make during the presentations, one for example, describing the enlarging of the core diameter from burying the cover/core inside the cover - "...it gets shorter and fatter, like we all do....". I could go on but, suffice it to say, WELL DONE!

[NickfromWI]

Originally Posted by Brion Toss

Hi again,
I mention elsewhere in the video that I much prefer stitching ó and invisibly stitching, at that ó to whipping. The purppose of both is to hold the splice together at low loads, when the "Chinese handcuff" effect is weakest. ...

What should we consider "low loads?" I like to pull on the eye of a non stitched single braid rope at various angles to see how quickly the handcuff action starts. What we do know is that the grabbing on doesn't happen immediately, and an arborist splice on the end of a climbing line is constantly being loaded and unloaded. Many times a day it sees those "low loads." Stitching or whipping is ESSENTIAL here.

We need to come up with a term for that "chinese handcuff" effect.

love
nick

[RonReese]

Nick,

Just so there's no misunderstanding, I'm not implying that stitching or whipping are not essential. I just want to be sure that the strength of the splice (not the security of the splice) does not depend on stitching.

I would be horrified to think that the support of my weight ( or more) would be dependent on how well and with what material an eye splice was stitched.

I have tested an unstitched, unwhipped eye splice in Velocity rope at 600# and it didn't budge even a fraction of an inch under repeated loading and release.

What I hope is true is that the strength of a splice is in the splice per se, not the splice plus stitching. I'm hoping that the stitching is there just to keep the splice from being inadvertantly pulled or worked loose at no or low loads.

Ron

[Dan Lehman]

Originally Posted by RonReese

What I hope is true is that the strength of a splice is in the splice per se, not the splice plus stitching. I'm hoping that the stitching is there just to keep the splice from being inadvertantly pulled or worked loose at no or low loads.

If you're concern about the splice strength is for the end of a climbing line,
then I'd think you need little concern (for maximum strength), as that needs only
so much strength (how strong is your body, e.g.?!). What's important is the eye
staying an eye (and not, er, winking or something); and doing so always.

I much prefer stitching ó and invisibly stitching, at that ó to whipping. The purppose of both is to hold the splice together at low loads, when the "Chinese handcuff" effect is weakest. Whippings look emphatic, but they typically engage the interior of the rope minimally. This leaves the support largely to compression from the round turns. This seems less effective, as well as being vulnerable to chafe.

!? I don't see how a few bits of cross-woven (stitched) thread/yarn so much holds
together collections of fibres: afterall, it's not as though one is impaling some solid
object--rather, the stitched lines run through (very small) space, strictly! And being
few and with minimal surface (sheath) contact, they can only generate so much
compression. How (much) does the Chinese finger-trap squeeze effect engage the
interior of the rope?!
Whereas with whipping, considerable compression can be generated (which, remember,
is supposedly only needed at "low" loads--not when considerable tension might so
elongate the material as to effectively reduce compression by reducing the bound
diameter). As for chafe, that depends upon material & usage; in the case of the eye
of a (tree) climbing line, it's readily visible/inspectable (unlike some other applications).
(Some 60-100# monofilament fishline & extended Strangle knots can make for a tough
binding.) How really safe from chafing can stitching be--as it too comes to the rope
surface (in small quantities)? If it's so "invisible", how will you know if it's intact?

--dl*
====

[RonReese]

Originally Posted by Dan Lehman

If you're concern about the splice strength is for the end of a climbing line, then I'd think you need little concern (for maximum strength), as that needs only so much strength (how strong is your body, e.g.?!). What's important is the eye
staying an eye (and not, er, winking or something); and doing so always.

I'm concerned about how to properly perform and terminate an eye splice in a rope. A properly done splice purportedly retains 90% or better of the rope's strength and I want to get every bit of the strength out of my splices I possibly can. We could ask why ANSI sets a minimum strength of 5400 pounds for an arborist rope, when all it's likely going to support is 200 pounds or so, AND that 200 pounds is often supported by two ropes giving a minimum strength of 10,800 pounds of rope strength.

A splice is a lot of trouble to put in a rope, so I might as well maximize the splice if I can. Samson Rope recommends stitching to terminate a splice in double braid and whipping for 16 strand such as the arborist splice. They actually test splices on their tensile machines so I presume they've tested all this. Maybe it doesn't matter a whole lot either way because it's only to hold the splice together rather than to enhance strength. Or maybe stitching is better in double braid and whipping in 16 strand.

From the Samson Rope website (double braid):
Procedure for Lock-Stitching Eye Splices
Stitch locking is advantageous to prevent no-load opening due to mishandling.
Material Required: About one (1) fid length of nylon or polyester whipping twine
approximately the same size as the strands in the rope your are stitch locking.
The same strands cut from the rope you are stitch locking may also be used.

16 strand:
Step 8b - Apply whipping to base of eye for a distance of about 1-inch
or 2 rope diameters.

I just spoke to Sherrilltree. They whip all their splices. They unhesitatingly said that the whipping only adds protection against the splice being inadvertantly pulled apart under no load. They also said that whipping or stitching adds no significant increase in strength to the splice.

11:00am EST - I just spoke to a splicer at Samson Rope. They really prefer stitching. He said that if you whip the splice, be sure it's the whipping method that passes through the rope as well as around it. Also he said, without any reservation that the stitching/whipping is only to keep the splice from coming apart under no load.

I looked at Yale Cordage's splicing instructions. They recommend whipping finished with what looks like two stitches over the whipping.

New England seems to think both is best.

Originally Posted by Dan Lehman

!? I don't see how a few bits of cross-woven (stitched) thread/yarn so much holds together collections of fibres: afterall, it's not as though one is impaling some solid object--rather, the stitched lines run through (very small) space, strictly! And being few and with minimal surface (sheath) contact, they can only generate so much compression. How (much) does the Chinese finger-trap squeeze effect engage the interior of the rope?! Whereas with whipping, considerable compression can be generated (which, remember, is supposedly only needed at "low" loads--not when considerable tension might so elongate the material as to effectively reduce compression by reducing the bound diameter).

Harnesses and webbing loops both rely solely on stitching and the stitching approaches the strength of the webbing.

Just to be clear, I'm not asking should a splice be stitched or whipped or nothing at all. I consider it a given that the splice will be secured with either stitching or whipping. What I was asking orginally was the purpose of the whipping and stitching. It seems that the stitching is to prevent the splice from being pulled apart under no load/light load conditions due to miss handling, etc. They actually don't say that whipping 16 strand serves the same purpose as stitching in double braid, but clearly a method of securing the splice is certainly called for. I now wonder if stitching is better for double braid and whipping is better for a 16 strand braid, or if maybe Samson has gone to stitching and just haven't updated their instructions.

[Brion Toss]

Hi again,
Dan, neither stitching nor whipping will add significant compression to add to the handcuff effect. Whipping might apply more, but even if so, whipping can be chafed away. In any event, both methods provide security through shear strength, not compression.
As for how we know if invisible stitching is intact, you may as well ask how we know if the buried tail of the splice is intact; of course they almost certainly are okay, as they can't be chafed externally, or degraded by UV. That leaves chemical corrosion or grit causing internal chafe, and those can be prevented/watched out for.
Whipping 16-strand might seem more attractive than stitching, as the looseness of the weave gives less "bite" to the stitches. Even so, I find that stitching is neater, chafe-proof, and easier done. You just have to be a bit more careful about it.
The strength of arborist rope might seem needlessly high, but there are a couple of compelling reasons for it: shock loads can easily multiply a person's weight (which could easily approach more like 300lbs at times, what with all the gear that arborists take aloft); and the factor of safety had better be at least 10:1, as arborists typically do not use secondary support lines, so must get their redundancy by other means.
Finally, I think Ron is exactly on in saying that it is a given that the splice will be either stitched or whipped. Or both. And by the way, the stitching will also keep your splices from floating apart in a washing machine...
Fair leads,
Brion Toss