US Hawks Hang Gliding Association

Hey guys I'm old school and I'm use to two sleeves per terminal. So looking at modern single sleeve method and I am assuming that extra cable on the bitter end,,,,swage,,, trim bitter end,,,dress with shrink tubing. I think that is the way to do it. Any pointers? How do I get really tight on that bitter end cut? Any tips on what shrink tubing to buy? Thanks.

I don't have any experience (other than watching someone else do it), but I did find an article on Wikipedia:



So be careful to get good advice!!

Been doing this since I was a kid. We used two sleeves back then and the second sleeve would be pulled up to the very bitter end This first allowed the end to be like a grab point to pull the cable until the first crimp, then the second sleeve crimped so that the bitter end was dead on even with the end of the second sleeve,,, then start the crimp on the near end of the second sleeve. This would cause the copper in the sleeve to extruded toward the bitter end , and if pulled off good the bitter end would be just inside the end of the sleeve but not so deep that it was not under the crimped part of the sleeve. That would be a dead on good crimp,, but quite achievable by a kid with just a couple of high school shop classes behind him. It's got to be done right so if you don't know how get some help and test your swage by pull testing,,,, the cable must break not the sleeve letting go!

Folks we have a answer to this question. I just reviewed two Wills Wing gliders of recent and new manufacturing. Wills Wing has been compelled to return to the original accepted method of two sleeves per terminal. I did get to see e method they used just before the return to accepted method.
So use two sleeves the same old way. I don't know who we have to thank for the motivation to get Wills Wing to return to the accepted method. I would not be surprised if it was the Mexican Government that said the alternative method was substandard. I did hear one person say what the word was about the change from Wills Wing,,,,, talk about a load of crap!

Offer for study:
https://chatgpt.com/share/6961dd97-b45c-8002-bc54-67ae74d74da1

JoeF wrote:Offer for study:
https://chatgpt.com/share/6961dd97-b45c-8002-bc54-67ae74d74da1

Thanks Joe! I've copied the text here in case the link's content disappears.

Hang glider steel cable Nicopress sleeving:
controversy over one sleeve or two after thimble?

There is a bit of a debate in the hang-glider/aircraft-cable community about whether to use one Nicopress sleeve or two after a thimble in a cable loop — and the nuance comes down to purpose, strength, redundancy, and fatigue:

== What the manufacturer (Nicopress) says ==

For a standard eye splice (cable loop around a thimble), *one properly-sized and properly crimped oval sleeve is all that’s required to reach rated cable strength. Eye splices normally use just one compression sleeve.

Two sleeves are typically used only when doing a lap splice (joining two lengths of wire) to equal the strength of a single eye splice.

This is the baseline standard used by cable manufacturers and aerospace riggers.

== Why some builders use two sleeves after the thimble ==

Practitioners in hang gliding and amateur aircraft fields sometimes double up sleeves for added perceived safety. The reasoning includes:

✔ Redundancy:

If one sleeve slips or is improperly swaged, the second is there as a back-up. Some builders like this for peace of mind.

✔ Perceived strength margin:

In rough use or uncertain tooling conditions, having two sleeves spaced a short distance apart is thought by some to distribute gripping forces better.

== ⚠ What critics say about two sleeves ==

There’s pushback against simply doubling sleeves out of an abundance of caution:

❌ No real strength gain in properly done eye splice

Tests done by hobbyists and vintage aircraft builders show that when one sleeve is correctly installed, the cable will almost always fail in the cable itself, not at the sleeve. Extra sleeves don’t raise that failure point.

❌ Potential fatigue issue

Two sleeves close together create a short, rigid section with no flex. Cables ideally flex between terminations; rigidity over a short span may increase fatigue stresses under repeated loading. Some experienced riggers argue this can be a detriment rather than a benefit.

❌ Installation challenges

If sleeves are too close or improperly spaced, the swaging process itself can become unpredictable. The manufacturer notes that when using multiple sleeves in a special termination, spacing and press sequence are critical to avoid unequal load sharing.

== Best Practices (Synthesis) ==

If you choose only one sleeve (standard practice):

Use a properly sized Nicopress sleeve for the cable diameter.

Ensure correct press sequence and number of crimps per manufacturer instructions.

Leave a small gap between the sleeve and the thimble so the sleeve has space to expand during crimping and doesn’t press against the thimble.

Verify with a go/no-go gauge after swaging.

If you choose two sleeves (builder preference):

Keep them spaced a bit apart (a few rope diameters) — not jammed up against each other.

Follow a proper sequencing pattern to avoid metal flow problems.

Treat this as a redundancy, not an official increase in rated cable strength.

== Summary ==

Manufacturer standard: One Nicopress sleeve on a loop termination is sufficient if installed correctly.

Some hang-glider builders: Use two sleeves for redundancy, though this doesn’t officially increase strength and can introduce its own issues with stiffness and fatigue.

The critical factors are correct tooling, swage quality, spacing, and inspection, not simply the count of sleeves.

Thanks guys, there are a few extra reasons that the two sleeve method is useful that are not structural integrity in purpose. I make use of a tag end of cable, pulling and putting a Bull Dog clip on to secure the sleeve, cable and thimble before compression. Then I trim the tag end, but I don't have to struggle to get the cut close or also deal with the bitter end. The second sleeve is crimped so that the bitter end is flush with the end of the sleeve before starting the compression, after compressing the extruded and flared sleeve end covers the bitter end. So to use one sleeve I have to relearn how to work with the rigging and as I take a critical look at how it is done,,,,,, they go back to the two sleeve method! And as I looked at the last wing built with the one sleeve method the long sharp angular cut cable bitter ends were encapsulated in an exotic and quiet durable shrink tubing. I don't know were to get such tubing. But for 6 bucks for the entire glider I can just use the two sleeve method . I wonder how much you have to pay for the special shrink tubing? So if I do a perfect job with one sleeve I am okay,,,, and I am not perfect,,,, and if I'm not that perfect that second sleeve may save the day. There have been cases of one sleeve slipping and one holding and yes the crimping job was substandard.

Thanks for the detailed explanation — that helps clarify where you’re coming from.

I think we’re actually talking about two different things: ease of handling during setup versus how Nicopress rates and inspects a finished termination.

• On the two-sleeve method:
  I agree it can make setup easier — having a tag end to pull on, clamp, or stabilize the thimble before pressing is practical. Using a temporary aid (clip, clamp, tape) during setup makes sense. Where I get cautious is when that second sleeve becomes part of the finished structure, since Nicopress strength ratings and inspection criteria are based on a single, properly made sleeve using the specified tool and press sequence.
  
• On “saving the day” with a second sleeve:
  This is where I think standards diverge from shop practice. Nicopress doesn’t treat stacked sleeves as redundancy — a substandard crimp is still substandard, and the system assumes defects are caught by gauge check or pull test before flight. If one sleeve slips in service, even if another holds, that’s really a near-miss rather than a design feature.
  
• On bitter ends and shrink tubing:
  Shrink tubing is fine for abrasion, snag prevention, and finger safety, but it isn’t structural and shouldn’t be relied on to manage geometry or workmanship. A clean cut and correct insertion depth are still the load-path solution. Plain 3:1 polyolefin heat-shrink is inexpensive and commonly used for this purpose.
  
• On Nicopress guidance:
  Nicopress’s own papers explain allowing extra tail so sleeve elongation during pressing doesn’t pull the wire back inside and reduce grip length. That’s an insertion-control issue, not a workaround for imperfect swaging. Their acceptance logic still rests on correct tooling, correct press sequence, and inspection.

Bottom line:
I completely understand why the two-sleeve workflow feels more forgiving. My concern is just keeping the finished assembly aligned with how Nicopress defines a predictable, inspectable termination — especially for flight-critical rigging. Convenience in setup is valuable, but it’s not the same thing as engineered redundancy.

Appreciate the discussion — this is exactly the kind of detail worth airing out.

Alright I am starting to get a picture of where we are going. First one sleeve is the standard of the industry. However, the one sleeve has to be done right. So let's review that and if I am off or short of some important detail someone please chime in.
The correct tool, The National Phone Company of Cleveland Ohio is ground zero for nicopress don't be fooled by expensive imitations others are good but why pay more for a knock off? Some nicopress tools have adjustable jaws but the QC should be done on every sleeve and each of the compression strokes. One should do a preliminary check at the time of each sleeve if the tool is adjustable so if it gets out of speck one catches it right away. This is not the QC inspection!!!
After checking how many strokes of the particular tool and sleeve are called for one begins. First the jaws of the tool should not compress the end of the sleeve, a small amount of sleeve must extend beyond the edge of the sleeve. It should be done so after compression the end of the sleeve has a small flair to it, a trumpet horn. The end of the sleeve should not be a round cylinder with a wire coming out of it. The wire will fray from this mistake, and if two wires come out of a sleeve that has this mistake degradation with be rapid.
Next because we are using the one sleeve method the tag end will pass 100 percent of the sleeve. However just for the information if one were to put a sleeve on a cable end then ALL of the strands of the cable need to extend out of the sleeve's compression zone. Ideally the strands stick out beyond the compression but end before sticking out past the end of the flair that trumpet horn. It is critical that all the strands pass out of the compression zone but if they don't end before the end of the sleeve the sleeve end should be covered anyway so don't stress.
The sleeve should be compressed a certain number of times. If the instructions are for two then three IS NOT BETTER THAN TWO. Also it is important that each compression has a tiny amount of sleeve between compression, the compressions should not overlap or compress the end of the sleeve so one needs to be careful about placing and planning so one doesn't run out of space along the length of the sleeve.

So the next controversy I have is the thimble. Back in the 70s they had us clip the tines off the thimble with a diagonal cutting pliers. This was supposed to help us get in tight with the sleeve. I never noticed any improvement by this trick and was wondering if anyone had any feedback on this one?

NOW IT'S TIME FOR SOME FUN[b][/b]Wills Wing always tries to cut cost in production.
Wills Wing was first that I know of to go from two sleeves to one.
Joe says that the shrink tubing is cheap.
Nico sleeves are 50 cents each and requires installation and QCing, labor intensive.
Two sleeves may result in inducing errors.
One sleeve properly installed is all you need a second sleeve helps not whatever.
Wills Wing has gone back to two sleeves
Cost more,may induce errors, doesn't help at all if things are done right.
THEREFORE [b] Ergo we cannot trust science OR we cannot trust Wills Wing
[/b]I trust science! Who can YOU [b]trust?[/b]