Discussion in 'Commercial Tree Care and Climbing' started by treeseer, Sep 25, 2007.
Has anyone had difficulty with these? www.rigguy.com
From what I can tell it's not been out there long enough. I think they came around 5-6 years ago. I was working at the country club at the time and they sent me 2 sample wire nuts.
There is at least one other discussion about it on the site.
I searched "wirestop" and "RIGGUY" and found nothing about it but a side comment by pancake. what thread are you referring to?
I belive these cable stops could potentially lead to greater metal fatigue failure issues, and also I suspect that the tree would have a more difficult time sealing the wound, as there would be movement and shifting of the cable within the wound as the tree shifts.
In most current cabling systems, the anchor is static, and the cable has some capability to move within the eye of the bolt or j-lag without bending the cable.
Does that make sense?
In a healthy tree the lag/throughbolt will be engulfed and the tree tissue will be on the cable anyways
I'm still partial to dynamic systems.
It seems that many companies are leary of the wirestop system, so it will take a while for failure reports to come out.
That is true, and that is also when you start to see cable failures happening, after the eye has been engulfed, the cable failures seem to usually happen at the "neck" of the dead end or wrap, if common grade cable.
This is just my observations over time, and should not be considered a substitute for a real scientific survey, of course.
Anecdotal observations have great value when there is no research done.
I've observed that "neck' failure too.
"I believe these cable stops could potentially lead to greater metal fatigue failure issues"
Here's the old thread.
I've attached a .doc file that illustrates my thinking and theories based on my observations. Diagrams are probably better than words in this case.
If it's the engulfing that increases stress on the cable (which seems obvious, but doubtful that could cause failure in a properly engineered system), that can happen with any static system, right?
Yes, It could potentially occur. Where i've seen it the most, is when the tree has grown over the eye of the hardware completely, and the eye of the cable. We're talking age as a factor as well as the repetitive flexing. My thought is that the wire stops promote the cable flexing in that fashon right from the get go, and might lead to earlier failures. Poorly designed systems would probably make that likelihood stronger.
That is why static cabling systems need to be periodically inspected and updated.
It's also reasonable to consider that a dynamic system with an invasive anchor could have similar issues, as it's hard to predict how a synthetic fiber will fare engulfed in wood.
Alanarbor- first off- AWESOME DIAGRAM! Very simple and easy to see what you're talking about.
I don't think what you are describing is what actually happens. I think that if the wire, in tension, were being pulled to the side while engulfed, it would open up the size of the hole at the end...ever so slightly- sortof like if you were to stick a stick in the sand, then shake it side to side. You'd end up with a funnel shaped hole. This shape would spread the stress over a longer portion of cable, lessening the chance of breakage.
I think we need pics and facts, because it is merely speculation on both of our parts.
You're right, Nick, It is purely educated guess work at this point. I think I see what situation you are describing, and maybe the cable failures are entirely age related, and don't have anything to do with the hardware type.
I'll make it a point when we remove a limb or tree with a cable in it, to dissect and get pictures, especially with an old cable that has been grown over. If we all contribute, we can probaly collect a lot of data, that would be fairly valuble.
You say regular cable, does that mean non-HSS?
Were the cables under rated for the load application?
Were the cables misaligned at installation, putting a "kink" in them?
IMO the moment of bend will move slowly inwards at the tree covers them up.
My understanding is that the engulfing of the cable actually makes the system stronger as the wood fibers surround it.
My concern with the wirestop is that it may move in the hole enough to confound the engulfing process.
That was one of the things that concerned me. I was concerned that the in-out in-out motion could continually break the callus growth, never allowing for the tree to grow over the cable, leaving continual access for pathogens to the center of the tree.
As far as callus overgrowth strengthening the system, I am inclined to think that would only occur to a signifigant degree when J-Lags are used.
I am really enjoying this thread, lets keep it going!
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