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Dingus McGee
Social climber
Laramie
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Topic Author's Original Post - Jul 6, 2011 - 03:19pm PT
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The Strength of ½” open cold shuts in pairs (ramhorn bend -mild steel-China made) was tested.
The ramhorn coldshuts were bolted to quartzite rock 8 inches apart and a 9.4 mm perlon rope was passed through them and attached to a load cell with a 5/8” clevis pin shackle.
Increasing incremental loading was applied with an 8000lb Smittybilt winch threaded with 11/32” dyneema synthetic cable and a snatch block was hooked to the load cell.
Results:
At approx. 3200 lbs a slight opening motion was noticed in the shuts.
At approx 3700 lbs a big opening motion of the shuts resulted the with the factory bent “L” near the pin end of the shut holding the rope.
Small taps were pressed on the control switch eventually reaching a stable loading approx 4250 lbs with the rope against the “L” shape.
The final tap of the force input pushed the load up to some 4450 lbs at which the rope sheath tore apart at the “L” of one ramhorn and the rope broke where it went around the 5/8” clevis pin shackle.
Some conclusions:
Ramhorn 1/2” open cold shuts are adequate for top roping anchors.
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Mighty Hiker
climber
Vancouver, B.C.
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Thanks, Dingus!
Ramhorn 1/2” open cold shuts are adequate for top roping anchors. At least until they're worn half through by morons lowering climbers directly through them, see-saw toprope sessions, and the like. And assuming that they're placed in sound rock, and well-spaced.
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Steve Grossman
Trad climber
Seattle, WA
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If you are out there testing it would be interesting to see how much rope wear lowers the failure point for 1/2" shuts if some body has a nice progression of worn shuts that size to donate to science.
Wear on the only point of attachment to the rock is my ongoing beef with cold shuts, welded closed or otherwise.
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froodish
Social climber
Portland, Oregon
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it would be interesting to see how much rope wear lowers the failure point for 1/2" shuts
Dunno, might actually test higher (the groove captures the rope and prevents bending.) Main danger from grooved shuts and 'biners seems to be rope damage from the sharp edges of the groove.
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Jaybro
Social climber
Wolf City, Wyoming
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The testor in the field, a few days ago,
Aren't you suppossed to be at that other place, um, by saratoga?
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 03:41pm PT
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Steve,
some people at Black Diamond tested half worn cold shuts and found them stronger than unworn shuts. Apparently the wear grove presents a much smaller radius for creating a smaller bending moment than the full round new steel offers. That is the rope becomes fixed in one place and cannot slide toward the pin end thereby creating a new and higher bending moment.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 03:43pm PT
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Jaybro,
Anne's hip was sore and so we split homeward this morning. Freddie has more photos of this test.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 03:50pm PT
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Steve,
I have applied hard surfacing rod to some cold shuts. The material I use is Rockwell C 64 or about 320,000 psi surface strength making them far more wear proof the any ss ring.
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Brian in SLC
Social climber
Salt Lake City, UT
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I have applied hard surfacing rod to some cold shuts. The material I use is Rockwell C 64 or about 320,000 psi surface strength making them far more wear proof the any ss ring.
Be curious to see your testing data on the wear of cold shuts versus ss rings.
My thought is that since a ring doesn't tend to wear in just one spot, they kinda do ok.
Have you done any strength testing on your hard surface cold shuts? Wonder if there's a strength difference. Do you apply this material with heat?
Will admit a dislike for open (or welded) cold shuts.
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 04:27pm PT
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The Chief,
bull sh#t may be your liking but Freddie knows more about the BD test than I do. I see you have made one major change in your hand breaking test. Did you pull in the same place as the rope pulls or on the end? Pulling on the end would radically increase the bending moment compared to the rope bending the shut by applying force in the grove.
Go ahead and use your massive anchors!
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 04:34pm PT
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Brian in SLC,
I have not got a chance to test these hard surfaced cold shuts in a heavy use situation. Rings are in another category of rappel anchors in that they require untying to thread. I suppose a ring could outwear a hard surface shut if it would keeping moving for successive pulls and not start to wear a grove.
I put on hard surfacing rod with an acetylene torch. The coating is a veneer and probably does not make them much stronger. You can get grade 70 cold shuts from Columbus McKinnon if you want substantially more strength, but I do not see the need in my location. Grade 70 chain corrodes less than mild steel I have heard.
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O.D.
Trad climber
LA LA Land
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Nice work, Mr. DMG. It's always good to quantify rather than speculate. Very nice test set-up, too. (I break rocks for a living so it's a treat for me to observe the behaviour of ductile materials instead of the usual brittle stuff)
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Dingus McGee
Social climber
Laramie
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Topic Author's Reply - Jul 6, 2011 - 04:59pm PT
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for The Chief and all those doing maintenance of bolting anchors.
Thanks for doing that job. I am somewhat of a minimalist but necessarily strive for adequate strenght with bolting hardware concerns as I put up a lot routes. The cost of the pieces and the weight of the items are major consideration for these adventures. I have seen a lot of anchors configurations posted here and others yet embedded in the rock and know a lot them are adequate. But I say to anyone not liking my implements that they are free to replace them with something more substantial and have fun doing it.
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Mighty Hiker
climber
Vancouver, B.C.
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My preference, at least in high use areas. Re-installed last weekend, on the upper Apron at Squamish. It's unlikely these would be used for toproping, though they'd stand up to a fair bit if they were.
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Brian in SLC
Social climber
Salt Lake City, UT
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I like that set up too, Anders, but, prefer to use the double ring anchor instead of the single. Point being that you can anchor off the top ring, and, thread the rope easier through the bottom. Bit more movement in the anchor is nice too, as, it'll tend to not cause the bolt hanger to move too, I'd think.
Rings are in another category of rappel anchors in that they require untying to thread.
That short coming is also why I think they last longer. Pretty common for groups to use these types of anchors, and, if the first person lowers off their own draws, and, the last person threads and either rappels or lower, it does save the wear and tear.
I also like that you can thread your rope, then, clip a draw to the upper chain like the one on the right above, and, TR through that if need be, then the last person (who might be a beginner and not that saavy) just takes out the draw and lowers off.
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klk
Trad climber
cali
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^^^^^ yes
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climbbjj
Social climber
Tahoe
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Ah, open shuts...
There must be some at the owens river gorge that need replacing every season. because clipping some draws in for marathon top rope sessions is too much trouble.
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Steve Grossman
Trad climber
Seattle, WA
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For high-grit places like the Owens River Gorge, somebody needs to introduce a replaceable brass pulley bushing into the coldshut setup to cut down the direct friction from the rope. People lowering repeatedly introduces an amazing amount of wear into the system and that doesn't seem to be changing any time soon. Even Musseyhooks wear out eventually!
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curt wohlgemuth
Social climber
Bay Area, California
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I'm really curious how fast the Mussy hooks wear out relative to open shuts. Do any regulars have even anecdotal knowledge of this?
I too hate the marathon TR sessions directly off shuts; I try to gently give such practioners advice about an alternative, but the general response runs the gamut from total cluenessness to outright aggression.
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