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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Original Post - Oct 12, 2010 - 08:12pm PT
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Tested some old hangers today. The 1/4" were tested in several 1/4" holes drilled into a 1/2" steel plate (the holes got mangled up and not all could be reused). The 3/8" hangers were tested in a 3/8" hole drilled in a 3/8" inch steel plate.
1) Pagan Gear SS (t = 0.134") 3/8" removed from service 6560 lbs (29.1 kN)
2) Mild, hot rolled steel (t = 0.116") marked MS (Mark Spencer?) removed from service at Balls 4240 lbs (18.9 kN). I didn't break the hanger but it kept shearing and prying (tension) bolts
3) SMC SS (t = 0.116") 1/4" removed from service 4310 lbs (19.2 kN). Again, I didn't have a bolt strong enough to break the hanger.
4) Similar to Leeper steel 1/4" (t = 0.087") removed from service 4050 lbs (18.0 kN)
5) Appears to be Leeper steel 1/4" (t = 0.083") removed from service 4240 lbs (18.9 kN). I tested this one with the 1/4" split shank button head it came with which I pounded into a hole drilled in steel. I had to cut the button head to length with a hack saw and found the steel very hard. I like the long spine on this one because it seems to reduce prying.
6) Aluminum (t = 0.186") 1/4" removed from service 3405 lbs (15.1 kN)
7) Kong galv steel marked "KG 2500" which I suppose means something like 24 kN, removed from service(t = 0.140") new 4900 lbs (21.8 kN)
Excluding corrosion and cracks, pretty much all the hangers are probably stronger than than any bolts of that size in rock.
Bolts are the unknown. Too many variables, quality of rock, quality of hole, etc.
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Steve Grossman
Trad climber
Seattle, WA
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Oct 12, 2010 - 08:35pm PT
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Nice work!
I especially like the SMC result as I favor those puppies and have backed up the manufacturer's claim that their stainless hangers have never failed in service. The plated chromoly ones are another matter. LOL
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rick d
climber
ol pueblo, az
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Oct 12, 2010 - 09:33pm PT
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as an aside, Geir Hundal et al recently tested two 1" star dryvin's in 2000psi concrete and found even with imperfect placement and pull via a #3 rivet hanger they failed at 940# and 810#. 1" max imbedded in the concrete.
A 1" rawl (marked R) split shaft was also placed about 2-3mm too shallow and pulled at 1050#'s.
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Juan Maderita
Trad climber
San Diego, CA
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Oct 12, 2010 - 10:57pm PT
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Hanger #4, described as "mild steel 1/4" and "Similar to Leeper steel 1/4" (t = 0.087")" was made by MHE (Marc Hughston Enterprises), in the mid 1980s.
It was stamped from chromoly steel and then heat treated. The hole should be somewhat larger than 5/16", as it accomodated a 5/16" Rawl Drive (buttonhead compression bolt).
Banquo, I'm curious to know if your sample really has a 1/4" hole. ??
Perhaps there was a previous generation of that hanger which I've never seen.
Marc gave me the dies 20 years ago to make a production run in thicker, stainless steel, for routes in Baja.
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Spider Savage
Mountain climber
SoCal
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Oct 12, 2010 - 11:33pm PT
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Good to know. Maybe I should feel okay to put up these old Leepers I have?
Naugh! Too nice in my collection.
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donini
Trad climber
Ouray, Colorado
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Oct 12, 2010 - 11:36pm PT
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Can't say I've ever seen or heard of a hanger failing.
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Clint Cummins
Trad climber
SF Bay area, CA
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Oct 12, 2010 - 11:45pm PT
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I've seen hangers broken off due to rockfall (different than breaking due to climbing use).
There were some problems with an old batch of Leeper hangers some years ago which led him to recall them. They developed cracks too easily.
Also the problem with the old Dolt hanger on the Nose rappel route which broke due to a hidden crack and resulted in the triple fatality.
There was also the recent incident at Index where 2 hangers failed in a fall, due to corrosion. (Brian just linked it above).
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HighTraverse
Social climber
Bay Area
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Oct 12, 2010 - 11:55pm PT
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donini
the combination of steel (of any type), aluminum and salt air will quickly destroy the aluminum. Often from the inside with little indication from the outside except perhaps a tiny bubbling in high stress regions like a bend.
So a stainless steel or steel bolt with an aluminum hanger should ALWAYS be suspect, except perhaps in the desert.
By the way, it doesn't just have to be salt air, acid rain (from dirty hydrocarbon combustion) will also do the trick, just more slowly than the salt air of the seacliffs of Maine or Corfu.
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Banquo
Trad climber
Morgan Hill, CA (Mo' Hill)
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Topic Author's Reply - Oct 13, 2010 - 12:23am PT
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Hanger #4, described as "mild steel 1/4" and "Similar to Leeper steel 1/4" (t = 0.087")" was made by MHE (Marc Hughston Enterprises), in the mid 1980s.
It was stamped from chromoly steel and then heat treated. The hole should be somewhat larger than 5/16", as it accomodated a 5/16" Rawl Drive (buttonhead compression bolt).
Banquo, I'm curious to know if your sample really has a 1/4" hole. ??
I guess I just assumed it was 1/4". I don't like 1/4" bolts but I do think there is a place for 5/16" bolts.
Can't say I've ever seen or heard of a hanger failing.
Donini - I agree, hanger failures are hen's teeth. But I did say "Excluding corrosion and cracks, pretty much all the hangers are probably stronger than than any bolts of that size in rock." When climbing, the bolt is probably more of a concern than the hanger but the bad part is that you can't see much of the bolt. Fixed pins are much the same. I want to do some testing of bolts but the task is daunting, too many variables. I think the results I got do show that many old carbon steel hangers are probably much better than the crappy bolts they hang on.
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Greg Barnes
climber
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Oct 13, 2010 - 02:54am PT
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Leeper hangers do break in climbing falls, it's a crap shoot. Not including ones that just rust and break (common in wet environments, not so common in Western US climbing), of the 3 generations of Leeper hangers (all look about the same), the oldest break around 1 in 50, the middle generation around 1 in 100, and the newest generation not known to break. But that was Leeper's results around 10+ years ago now.
Possible mechanism for the breaking was stress corrosion cracking, but not known. Leeper said that hangers which were visibly dented at the bolt (i.e. during installation the bolt was smashed in hard enough to bend the hanger) were more likely to fail.
Old thin SMCs break at least as often as Leepers - and you see those cracked more often as well.
[note - the 3 generations of Leeper hangers can be told apart with a caliper - the metal thickness in inches was 0.062, 0.080, and 0.090 if I remember correctly]
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Marc Hughston
Trad climber
Dana Point
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Jan 19, 2014 - 11:37pm PT
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I spoke to Ed Leeper many times circa 1986, and he gave me his recipe for the chromoly steel material thickness and Rockwell hardness number to shoot for. The Yates brothers encouraged me to make a hanger that two biners could fit into side by side, and that's why I made the hanger in that shape. I've thought for a long time that it was the bolt itself, the shape of the hole that received it given the pounding with a Rawl Drive, and the surrounding rock that really made up the potential failure point. This is interesting stuff.
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bhilden
Trad climber
Mountain View, CA/Boulder, CO
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Aug 31, 2014 - 10:48pm PT
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Bump for some Banquo love!
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Roger Brown
climber
Oceano, California
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Banquo's threads are always worth re-reading. I agree with his statement above that a broken hanger is a rare thing. I found a couple badly cracked thin SMC hangers this season but no broken ones. Also, that old hanger can often be checked out before clipping, but the bolt is another story. This season, while seeking out those remaining 1/4" bolts in "The Valley" I have been swinging around to nearby routes with those fatty buttonheads to test the spinners. I am finding that the spinners pull a bit easier than the non-spinners. Maybe it just seems easier because it is easier to get the puller under the hangers. One thing for sure, all buttonheads are suspect. Spinners just a little more so. Whether 1/4" or 3/8" most buttonbeads are pretty solid and yes the fatter the better. But with that said, I was supprised at how easy a few of those fatties pulled. Lately, I have been suspious of everything. I know those 5-piece supplied to me by the ASCA tighten up in less than 4 turns, so I question anything with a bunch of threads showing and no markings on the threaded end to indicate length. Well, I'm getting on a roll now and all this belongs in another thread, so.... Thanks Bruce for bumping this thread.
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Jaybro
Social climber
Wolf City, Wyoming
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I've never seen a hanger break in front of my eyes, but I've certainly come upon several broken hangars on routes on bolts. Generally some every season. There's no shortage.
Dingus McGee has done Extensive testing of this sort, even posted videos of it here. Maybe he'll chime in on this!
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