cabling 2 stems less than 3 ft apart

Kathy_Holzer

Kathy_Holzer

Location
Seattle WA
hey guys,
i have a job that's puzzling me. i've been doing (i know, old school) steel cable systems for 10 yrs and i've finally encountered a situation where the hardware i am used to is completely useless. i typically use cable grip ends, ammon eyes, 7 strand high strength steel cable, etc. in this particular cypress tree, the two stems that make me nervous are (at 2/3 above lame crotch) less than 3 ft apart, and my good old steel system has a minimum spread apparently of 3 1/2 feet or something. pigtails (cable grip ends) would have to be cut to fit into this tight spot, and who knows what that would do to their strength rating.

so. i just ordered the trial kit of standard cobra cable, thinking this might be my best solution. the tree is not hazardous (yet) but i can't in good conscience prune it and walk away w/o installing a cable system of some kind. my only other idea is to splice some technora in a sheath of some kind (light blocking) to j-lags with locking brummels and hope for the best. unknown strength rating to that system though, of course.

anyone encountered a similar situation and come up with different solutions than the ones i'm mulling over?

i'd love to get some feedback on this one, as it's sort of a first for me. the tree doesn't get too much wind but i've seen too many of this type of cypress have whole stem failures from included bark/narrow attachment points.

thanks in advance.
k.
 
Kathy,

I recently got my first Cobra kit. There is an illustration in the instructions that shows how to use the Cobra in real short spans like that. Looks like it would work well.
 
I think that any of the non-invasive systems is a good choice. You can do an end to end splice so you'll have a large loop. I've done several like that.

If you choose to stay with steel cable you could go to a larger size mild cable and do seven strand wraps like the old days. I've done that where space was a premium like you've encountered here.

Have you considered either of the cable end grabs? The ones with the two-piece tapered fittings? I think they have some merit with only a small possible drawback.

Can you take pictures of the installation and share them?

Will you be in Nashville?
 
1.Cut the cable dead ends (grips) 4 inches each which gives you 8 inches, 2 more than you need.

2. Use crosby clamps. (never saddle a dead horse)
 
hey tom,
yeah, i'll try to remember to bring the camera that day. endless loop is a great idea, i hadn't thought of that. i've been using the cable grip ends for years (we call them pigtails for some reason..). i did do one cable in a short span where i actually shortened the pigtail by a few inches but it doesn't sit well with me and i worry about that tree - big old cryptomaria that probably should have been a removal but i couldn't talk them into it.

i'll be in nashville but am not competing this year, due to another event i need to train for in october. i may be judging the women's masters though- quite an honor for me.

see you there, i assume ?
k.
 
[ QUOTE ]
2. Use crosby clamps. (never saddle a dead horse)

[/ QUOTE ]

what's that? is it the little clamp with 2 nuts and one u-shaped bolt threaded at both ends? if so i can't bring myself to trust those things with much weight. never seen ratings on them.

and eric - oh yeah, i've seen those. but what happens if the span you need to cable is between two of the sizes - say between the 30 and 36" ? i guess if it was super slack it would still be so me insurance against stem failure but not a very elegant solution to the problem of keeping the tree from splitting out. rot is not the issue here, not yet anyway - it's a fairly young tree with about 2 ft of included bark/compression at about 4 ft where the two stems originate. really heavy foliage, one sided growth, not a rosy future for this guy w/no cable methinks.

thanks for the ideas gentlemen. anyone else?
k.
 
Kathy,

"what happens if the span you need to cable is between two of the sizes - say between the 30 and 36" ?"

Just install it a little higher or lower.
 
Can you use a threaded rod cut to length at the union?
What distance do you mean by 2/3 above the lame crotch?
[ QUOTE ]
two stems that make me nervous are (at 2/3 above lame crotch)

[/ QUOTE ]
 
How about good old common grade cable with a hand made splice? I think that the closeness of the stems could interfere with tightening using a come along so you could install withh extra thread sticking out towards the other stem and tighten by screwing down the nut.
 
Hi there,
Completely agree with you, Cobra, or any other dynamic system will be fine for that job. With Cobra you´ll get a minum of 20 cm stretch on account of the rubber dildo alone, so the two stems will be able to move nicely up to a certain point before being gently eased to a halt, allowing the tree to carry on growing but being safe while it does it.
if you´ve any queries there´ll be loads of guys who´ll give you tips on fitting your Cobra (which is easy anyway).
All the best,
Adrian, Berlin, Germany
 
It's NEVER a good idea to cut down the lengths of the pigtails/treegrips. They work at the rated strength because of the internal friction that's designed into them.

There are right and left hand lag eyes available. They allow the cable to be spliced and then tightened by counter rotating. Through bolts are easier though.

See you in N'ville.
 
"Can you use a threaded rod cut to length at the union?
What distance do you mean by 2/3 above the lame crotch?"

thanks kevin, i hadn't thought of installing a rod w/o a cable above. never done that before, though in this instance it might be sufficient. 2/3 above the weak attachment point is (or at least i understood it to be) the correct height when installing a cable system - is that no longer true with new research or something? (if you're asking about the actual height, i'd say the tree is maybe 40 ft tall.) my main complaint w/cobra is that it has to be installed at a branch or the cable can slip down, and in many trees (around here anyway) that wouldn't give me much control/choice about that ratio.

ok cobra lovers, tell me about the height-above-weak-crotch ratio. i'd be happy to switch over to dynamic cable systems if it weren't for this issue, and also i guess the issue of 10 yrs down the road what has the sun done to the strength of the plastic.

thanks for the thoughts!
k.
 
[ QUOTE ]
How about good old common grade cable with a hand made splice? I think that the closeness of the stems could interfere with tightening using a come along so you could install withh extra thread sticking out towards the other stem and tighten by screwing down the nut.

[/ QUOTE ]

this would be the perfect solution if i knew how to splice cable. now i'm not old-school enough ! /forum/images/graemlins/grin.gif

k.
 
We use rust resistant chain in situations like that. Just make sure the J lag fits through the chain eye.
Tom is right, quick ends are NOT supposed to be cut. They are designed to use the full length of the grip to make the strength standard.
 
I've found that very short spans of steel (common grade) have a very high tendancy to break. In fact, every cable that has failed from among all those I've installed has been in very short spans. Something with the constant flexing over a short distance (thus stiffer response to compression) causing greater metal fatigue than over a long distance, I think.

Definitely dynamic is called for, and I agree with Tom about the end to end splice on a loop.
 
yeah go with the hand slpice. it is not hard to do..if this helps...
runs cable thru thible and bend into greek omega symbol
fold short end to long end. slowly unwrap short end and begin wrapping individual lines around both side of cable.
probly not the best description. too bad i cant just show you. its real easy
 
Fred and Kathy...
I would do it as Chad suggests. We have not had failures of short spans any more than longer spans.
Would a second cable above the first mitigate failures, Fred, ya think?
 
well, i cabled the tree today using the medium size cobra. hopefully the shortness of the bury won't cause the splice to pull out. here are some pics if anyone's interested.
 
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