Rigging ring as primary rigging point for negative rigging.

Alright, so I'll be specific. I have seen 35 year old aluminum carabiners used for speedlining on old ultra dirty/gritty ropes, and when 300#-400# pieces came down the 120' run, they would show visible wear. One of those biners wasn't used for big pieces anymore because it was 45% cut through after so much use. I have seen some horrible shit, and this was achieved only by ignorance, willful or otherwise.
 
This configuration works good for me
Prussic small loop on large deadeye for adjustable girth
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Steve Connally said:
David has a ton of data on this. Unfortunately I doubt he'd want to revisit the conversations.
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Back when David was introducing his ”x” rigging rings to the industry, I had a training in Virginia somewhere. I contacted David and asked if I could strop by his place and check out the rings and ask some questions. He generously agreed. I stopped in on my way south.

I remember him describing to me how he was using his crane to break test ring set ups. For those of you who know David, you can imagine the massive drops he used with the intention of failure!

To surmise our discussion he said anything less than three rings would break the rope at the rigging point (rings). When he used three rings the rope broke at the load.

I always figured it had morre to do with the third ring changing the angle of enter/exit as opposed to bend radius.

I don’t rings in top down rigging as it annoys me they are not mid line detachable.
David also generously gave me a set of rings which are still in use to this day.

my .02

Tony
 
I was doing some rigging for an art installation, using 1/8 wire rope. Pulled a bight off the spool and it was destroying my hands so I snapped an aluminum locking carabiner to it. Under no load other than pulling it off the spool it cut it half way through.
Dirty sandy rigging lines are abrasive as hell. We work on glacial till bluffs and I’ve been alarmed at the wear on a alum ring to ring, with taking effort to keep things cleanish.
 
Tony said:
Back when David was introducing his ”x” rigging rings to the industry, I had a training in Virginia somewhere. I contacted David and asked if I could strop by his place and check out the rings and ask some questions. He generously agreed. I stopped in on my way south.

I remember him describing to me how he was using his crane to break test ring set ups. For those of you who know David, you can imagine the massive drops he used with the intention of failure!

To surmise our discussion he said anything less than three rings would break the rope at the rigging point (rings). When he used three rings the rope broke at the load.

I always figured it had morre to do with the third ring changing the angle of enter/exit as opposed to bend radius.

I don’t rings in top down rigging as it annoys me they are not mid line detachable.
David also generously gave me a set of rings which are still in use to this day.

my .02

Tony
Click to expand...
Thats a cool story. I talk to David at the least daily. I'll try to remember to mention this. I still have the rings he gave me as well. I tend to use 3 most of the time but luckily I haven't had to rig anything massive in years and years and years.
 
I'm still a sucker for the dmm rigging blocks for anything on the bigger side.... Have to be doing something really questionable to get into trouble with one of those!
 
Here's a physical (physics) observation about double rings. They don't accomplish what they are advertised to do.
I understand the reason for using double rings is to increase the bend radius so there's less internal stress in the rope.
As I look at the double rings, I don't think they actually increase the bend radius at all.
Instead of having a "half-wrap" on a small radius (single) ring the double ring setup has a "quarter-wrap" on a small radius ring separated a couple inches from another "quarter-wrap" on another small radius (single) ring.
The rope still needs to bend at that small radius size, putting extra tension on the rope fibers away from the ring and extra compression on the rope fibers closer to the ring.
To exaggerate the point, imagine 20 rings connected somehow in a straight line - the rope would still be taking a relatively sharp bend on both ends of the 20 rings and only going straight between the two ends.
If a larger bend radius is desired, then a larger ring is needed, not just putting two small rings side-by-side.
I may be wrong, but that's how it looks to me.
 
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Best theory I could figure was the horizontal span across the two ring centers gave space for the internal shear(?) rope stress (inner/contact fibers getting side-and-axial compression whilst outer fibers mostly tension, with side compression/without the axial compression) to bleed out from the exact length of the 1/4 wrap location. Bleed out thus reducing stress.

Pure hypothesis on my part.

Agree actual bend radius same on 1, 2 or 20 rings.
 
The way I think of it without any clear conclusion is yes the bend radi is the same but spread out. Accounting for the rope construction and diameter this can load different strands as they complete their full turn around the braid. So perhaps spreading out 1/4 bends is better?
also less rope in being compressed with 1/4 bend vs a complete U shape.
there is certainly more going on than meets the eye. It would be interesting to see actual break testing on one ring vs two or three.
 
evo said:
It would be interesting to see actual break testing on one ring vs two or three.
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I've often thought about break testing - in the case of the rings, I wonder if some engineering department somewhere would be able to measure how much heat is generated in the ropes in different bend/ ring cases - maybe IR readings. Internal friction would probably be dissipated as heat as the fibers do their thing. Just a thought. Or is it the single malt again?
 
ghostice said:
I've often thought about break testing - in the case of the rings, I wonder if some engineering department somewhere would be able to measure how much heat is generated in the ropes in different bend/ ring cases - maybe IR readings. Internal friction would probably be dissipated as heat as the fibers do their thing. Just a thought. Or is it the single malt again?
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Certainly a single malt pondering
 
Serf Life said:
Too bad he can be a dick online.
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He can act like one in person too... he's a bit of a micro manager, though I can't really fault him as that's a character flaw of mine as well.

I had a near miss with a freak accident when he mixro managed my position before he madeva cut...

I was down doing some video taping at x week. David, Lawrence Shultz, and August Hunicke were in the tree. I had filmed a lot of the action from the ground, but had put the camera down for this cut. It was a big dead oak limb that was going to swing a good ways into the rigging. I saw the set up and stood well away from the action on grass in the middle of a huge lawn... There was absolutely no chance I was in danger, nor was the possibility that the climber would even have to consider that possibility. I eas good. But David insisted that I move because I was potentially standing on common ground owned by the neighboring condominium association. There was absolutely zero chance that was going to be a problem. But, OK... it's your job and your show. I was your guest. You're in the tree. I don't want to make adeal over basically nothing... so where do you want me to stand?

He says "stand there"... I go to exactly where he tells me to stand, which is a good 50 feet away from the drop zone. Any reasonable person would have thought there was 0% chance of me being in danger there...


But it turns out that it wasn't quite zero. It was more like 0.01% chance... that's one in a thousand... it was probably even less than that.

So this monster oak limb makes a big swing into the rigging. The tips came very close to the ground. And just as it started swinging up past the low point on the pendulum, a big dead side limb let go and came flying right at me. Even though I was a good distance away, it was moving so fast, there was no chance of running. It was coming at me horizontal, as in parallel to the ground.

There was only one thing to do... Duck... I bent over and ducked as low as I could just as it sailed right over my head, with only inches to spare. If it hadn't I was going to the hospital, maybe by ambulance.

In 40 years of tree work I've seen a lot of freaky things... This was in the top 2 or 3 of all time. The odds of that limb letting go at that exact moment were miniscule. Anyone that saw that happen would never forget it. I certainly won't.
 
Ghostice, there's merit in your point. Like a cutting tool, a percentage of the heat goes into the tool and a percentage goes into the workpiece and another into the chip. In our case it splits between the rope and the ring. Ring is pretty straight forward you can see very near the rub surface with an IR cam and the heat spreads from the contact area to the rest of the ring. Rope has surface rub and internal flexural losses - two sources of heat. I believe nylon and polyester cordage have relatively crappy heat transfer compared to aluminum, so by the time the rope passed by the ring who knows what the heat distribution in it is and how "settled"/spread out it is, Thus an IR cam might not be able to pick up what's going on in the rope, except perhaps surface glazing. Maybe if a short pull was done so all the affected rope stayed in frame the "settled" rope heat distribution could be used as a metric, waiting however many seconds it takes the heat to settle/distribute in the rope.
 
I've made the comment before, but I wish we had a Ryan/HowNot2 in the tree industry to test these things. The stresses that come from arborist work are so different than rock climbing, rope access, etc, especially concerning dynamic loading that no one outside the industry could accurately measure and test for it. And sorry, it won't be me, I'm too anti-social :p
 
I have wondered if he would want to do tree stuff. He's 1.5 hours drive time from me.


15 years ago, I figured out how to Never risk a factor 2 leader fall... thought of reaching out to him, but I am so busy with tree work.
 
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