New Arborist Cabling Alignment Tubes

jomoco

I've been cabling trees here in San Diego for a long time now, and have managed to achieve a modest reputation as a cabling expert over that time having installed hundreds of cables successfully.

In my opinion, the most difficult aspect of installing any cable correctly is getting the cable aligned with the branch attachment hardware throughbolts to form a perfectly straight line, which is critical not only to the strength of the system, but also to avoiding rotational torque being applied to the cabled leaders when the wind blows and tensions the cable and hardware.

It is almost impossible to achieve a perfectly aligned cable by eye when drilling the hardware throughbolt holes in each leader to be cabled, and if the holes drilled are out of alignment to any degree, that is the exact degree of rotational torque that will be applied to the cabled leaders each time the wind blows with sufficient force to straighten the cable and throughbolts into alignment. If you are only a few degrees out of true alignment, the torquing applied to the leaders in the wind is minimal enough not to cause a serious problem. However, being out of alignment by more than 3 degrees can over time cause the cabled leader to lose it's structural integrity and fail, with possibly disasterous consequences.

One of the recent cabling jobs I was contacted to evaluate and correct involved large Torrey pines that had been cabled by an amateur that installed his cables way out of alignment. This resulted in the structural failure of a huge 26 inch leader right over the boardwalk on the beach here on San Diego bay. Almost every cable this guy had installed in these two magnificent mature Torrey pines was far enough out of alignment to cause serious problems as a result of the daily onshore prevailing winds.

My bid to replace all of the cables in both these beautiful Torrey pines actually exceeded the cost of removing them, but the board of directors that managed the luxury highrise condominium towers on the bay gave the go ahead anyway because the trees were so highly prized by the hundreds of residents living there.

The go ahead from the board was given in the early summer of 08, which caused me to insist on delaying the job until January of 09 to avoid stressing the trees during the hot summer months by drilling new holes in them for the new replacement cables.

It was during these intervening months that I contemplated how to achieve a better means of drilling perfectly aligned holes through each leader I intended to cable on these trees.

This is what I came up with, I call them cabling alignment tubes.


I would like to discuss ways of improving these tubes in this thread in an effort to advance quality cabling practices in an overall sense in the tree industry.

Best regards guys,

jomoco

jim1nz

Hey mate can i ask what kind of hardware you use exactly? Where are you generally installing the cable in relation to the split union and the top of the tree? Are the cables tight or loose? How are you working out the breaking strength of cable required?

We are using rated slings, shackles, and wire cable with ubolt clamps. I can get photos if you want, its interesting to compare systems. Our static systems are always always used in conjunction with dynamic cobra systems.

Where have you done research on bracing? How did you come up with this 'rotational torque' theory?

May be after a bit more info i can provide some constructive critisism on the drilling system you have made up there. Cheers

jomoco

Hi Jim,

I'm kinda old school about my cabling hardware, Chicago galvinized drop forged throughbolts, EHS 7 strand galvinized cable, galvinized dead end grips.

I stay away from the Cobra system, don't trust it, don't like the girdling aspect of it, but appreciate the logic behind the dynamic give of the system when applied to a non-fault added support scenario.

And with all due respect, rotational torque being applied to the leaders of a mis-aligned cable is not a theory, but an engineering fact.

This is just one of the mis-aligned cables I had to replace in one of the Torrey pines I spoke of.



This is a vid of my cabling tubes in action.



Best regards Jim,

jomoco

Eric Frei

I'm surprised that rod didn't bend to get straight in alignment with the cable.

I'd like to see how you tension these cables too. Or do you like use a rope system higher up to pull the stems together, install the cable then release the rope system? What about the termination ends, spliced, how you go about that would be good.

Cabling here in Australia is simply not done a lot, any input from cabling veterans would be benficial. You could also drill right through and terminate with the Rigguy system.

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jomoco

Hi Ekka,

I tension my cables with the throughbolts by simply tightening the nuts on them until the cable is taut.


I'm particularly distrustful of the Rigguy system because of the way it separates the cable into single strands, then squishes each strand in the wedge and ferrule compromising the galvinized coating on each strand in a hidden from view area that can't be inspected.

I have spoken with Rigguy on the phone to determine if any 7 strand cable manufacturer has ever endorsed his system for use with their cables? The answer as I suspected of course was no. Another aspect of his system that is very questionable in my opinion is the cable entering the drilled hole being subject to side loading and bending the cable in the same spot repeatedly over time, not only does this have the potential to weaken or break the cable eventually, it can also flare out the entrance hole due to abrasion causing unnecessary further damage to the tree over time.

None of these detrimental factors apply to the old school traditional cable to thimble to eyebolt method because any side loading is isolated at the thimble eyebolt ring junction, steel on steel rather than steel cable on wood with the Rigguy system.

These two major drawbacks inherent to the Rigguy system along with the fact that his system has only been in use for 4-5 years were huge red flags for me as a cabler with installed old school traditional cables well over 20 years old and still holding up very well.

Best regards Ekka,

jomoco

southsoundtree

Jomoco,

you seems to spend time thinking outside the box. Interesting set-up for the cabling. When do you see this coming on the market?

The tree slave is interesting, too. It was a related video Is it such that it winds up by the tree/ ratcheting mechanism on the drum, then released when all that potential energy becomes kinetic attached to a generator? How much do you think that can generate in an average day or year? Seems like it will have to be attached to the top of the tree at a low angle to the ground to maximize. Perhaps a large gear attached to the lever and a small gear attached to the drum would increase your movement.

treerep

Jomoco, That is possibly the worst cable system I have ever seen installed. The engineering FACT you speak of is exacerbated by your complete lack of understanding in how to install a cable. I only pray I am wrong and you are only 2 parts through the process in that picture but it seems unlikely as I see no Bark tracing.... The eye (along with a washer) should be firm against the trunk and the remaining bolt should be cut and peined for future growth and possible nut release. The engineering of the torque after the union of bolt and trunk can be discussed at length but it seems as though you have missed the boat mate.

treerep

Ecka, The best termination is done in a hard system through a speed wrap which is simply a Chinese finger trap for Wire. Hard to find In australia but the done thing in the US. Currently working with a Melbourne company for Mass shipment will keep posted.

jomoco

Well fortunately for me you are wrong Treerep, the picture I posted was of just one of the mis-aligned cables I was hired to replace.

Lack of understanding eh?

Too rich mate!

jomoco

jomoco

The cabling alignment tubes will not be on the market for some time Southsound, probably six months to a year.

The tree slave's output is entirely dependent on wind conditions in the area.
It works much like a childrens wind up jack in the box toy. It was at the point I figured out how to slave six binding drums to one large ratcheting arm much like a six cylinder engine to provide a constant power output in a 10 mph wind, that I invented the windrocker. It's essentially a pair of manmade artificial trees working together in sequence to provide a constant power output of 5.5 Kw in a 9.5 mph wind.

Here's a computer animation of an early wind rocker design in action.


jomoco

treerep

apologies jomoco I misread your post a little though this is still the worst cabling job I have ever seen. The pic got me a bit riled.

jomoco

No worries mate, we all get riled and make hasty judgements at times.

Work safe!

jomoco

Eric Frei

I'm eagerly awaiting information on tensioning and terminating of steel cables, good details, pictures and video.

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treerep

Ecka, the tensioning is almost negligible and in fact on a deciduous tree it is best to cable slightly loose in the winter season so leaf weight will actually take the tension. Speed wraps can be found in every Sherril catalogue and it is simply a case of cutting wire to length and using a few centimetres of thread to make the cable taught. I can probably scrounge a few pics but I am sure the guys in The US will have a lot more. In the situation of the picture above from Jomoco whoever installed the cable used an eye boly far too long but if you can imagine a similar scenario with maybe only 25 - 30 mills of rod exposed before the eye and then the nut was tightened then tension would be sufficient. If that makes any sense.

Samdavi

Is there anyone in El Paso, Texas that can cable a large old mulberry tree?