Quote:
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.
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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.
Quote:
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).
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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.