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JLP
Social climber
The internet
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Chiloe,
4mm vs 5mm radius x-section: over 2x the stress, therefore half the strength. That's for a straight bar. Tortuga has a stress riser with the ring that the other bolts out there don't. Corrosion of Ti is great, but that ring obviously needs to change. Strong design is not the same as strong material.
I am not a metalurgist, I am a development engineer. I make things work and I've been doing it for a long time.
How often have I seen this - 1 million reasons why the design can't fail - yet there is a failure. It's the stupidest mindset you can possibly have as an engineer. Remember all the BS about how styrofoam could never puncture the space shuttle wing? Look at CCH - that guy will be a pole dancer for the cowboys in Laramie in 2 years. Tons of data on his website about how great Aliens are and how they will never fail, but not one of them addressing why so many are failing.
BSLC - specs? You are picking through sand on the beach wondering why the hurricane hit. All alloys are in the same relative spectrum - and who even cares unless you have the exact load that broke it? There are several pictures of the broken item posted above with a pretty clear indication of why and how it broke - bending, torsion and tensile loading all at once - do you know Mohr's Circle?
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stevep
Boulder climber
Salt Lake, UT
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It broke further down the shaft because of a bad placement. Maybe a stainless gluein survives there, but maybe not. A bad placement is a bad placement. At least some of the stainless glueins I've seen have similar rings (which probably aren't machined in those either). Absent direct evidence that a stainless bolt in similar circumstances survives longer, I don't know that I'd call the manufacture faulty.
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tradmanclimbs
Ice climber
Pomfert VT
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From a photographers point of view the shiny spot may be a reflection/hot spot in the exposuer of the photograph and not an accurate depiction of the actual physical object.
From an old farts point of view who has broken lots of metal things, the shiny part is allmost allways the last bit to break.
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stevep
Boulder climber
Salt Lake, UT
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And here's the technical spec for the Petzl Collinox, one of the standard stainless glueins. Note the diagram showing that you should not install these with the shaft exposed. Note also the statement under Strength:
"The anchor breaking strength values indicated in the table depend
upon the quality of the supporting medium and the quality of the
placement.
PETZL cannot be held responsible for poor anchor placements."
I'd say the same goes for Ushba, or any other type of bolt.
http://en.petzl.com/ProduitsServices/P55%20COLLINOX%20P55500-E.pdf
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Evan Jackson
climber
Austin, texas
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Wowser, there's a whole lot of speculation without a whole lot of knowledge.
Please, if you are not familiar with the route keep quiet. Nothing compares to having firsthand experience with the route and the way the bolt was placed. Speculation about the environment/conditions only leads to more nonsense.
To clear a few things up, the hole was drilled perpendicular to the ceiling not at a 45. The bolt was fully seated with the eye pressed firmly against the rock the same way it’s displayed in the manufacturers instructions. Despite a clean shaft on the broken bolt glue oozed out of the hole during placement. Thus, the bolt was properly seated. Glue is still visible in the hole were the bolt used to be; it extends all the way to the exposed rock surface. Please, take a look at the lefthand side of the eye and you will see that the straight part of the eye does extend into the rock at a true vertical orientation. The dark shadow that people mistakenly believe is the shaft extending at a 45 is actually extra glue that oozed out during installation.
I will be there this weekend and gladly take pictures. I’ll try sticking a pencil in the hole so all can see its access runs normal to the roof plane.
The bolt was placed by individuals with years of experience and literally hundreds of bolts to their name. It was placed correctly according to the manufacture’s instructions and common sense.
Please, if you are not an engineer be quiet, layman speculation is what leads to rumors and false climbing myths.
The bolt broke at the “threads” this could have easily acted as a stress concentrator.
The fracture surface does exhibit signs of fatigue (a common failure mode in both steel and titanium). The small shiny area could be an area of slow crack formation. The uniformly tiny dimpled area is characteristic of fast fracture. Which occurs only after slow growth has reached a critical point.
The bolt was placed in such a manner that falls were small and never came close to a class two. It was mostly loaded with body weight only. Another crack is also present near the weld. Something else is going on here. Two cracks in one bolt that only handles low force is peculiar. Even the weld quality differs between this bolt and the picture that Chiloe posted.
Corrosion is not an issue; the bolt was placed in a limestone roof. It was never exposed to chemicals and barely even saw moisture.
As SteveP stated even 6sigma standards can yield a product that fails. Perhaps this truly was the lottery winner.
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Dr. Rock
Ice climber
Castle Rock
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Thank you for that.
I will try and not speculate, but I do have a little more background info.
Yes, I kind of went of half cocked there, hell, I don't even have the parts.
I better go yank the Pirate pic.
Sorry Lord Slime!
This hanging load can be classified as a Satic or "Dead" Load.
There are two types of Static loads.
Compression and Tension.
So this would be classified as a Dead Tension Load.
The load that the part will handle is determined by it's Tensile Strength.
You can easily look up the Tensile Strength of various metals on the web.
Lets use a worst case scenario, Al alloy.
Tensile Strength of about 40,000 lbs per sq inch.
(Love those English Units, no jokes please)
OK,lets really jack up the odds and say the Net Bolt Diameter, as opposed to the Total Diameter (the scoring reduces the Net Diameter)is a 1/4 inch.
OK, Pie R Squared is the area of a circle.
So, a 1/4 inch bolt has a 1/8 inch radius.
Area is therefore 0.05 Sq. Inches.
Heck, lets drop the Tensile Strength down to Shear Strength, which is about 30,000 lbs per sq inch.
So 30,000 Times 0.05 = 1500 Lbs.
That is for a 1/4 inch Al bolt, using Shear, not Tensile.
Since the equation for the Area of a Circle is Quadratic in r, the Tensile Strength rises rapidly as the diameter is increased.
Other things to consider:
Glue expansion rate vs Ti alloy expansion rate.
If the bolt could turn, then it could be bent back and forth.
In order to deform a steel rod, you have to apply a force greater than it's rating.
When this happens, the metal stretches as the force is increased, until a point is reached where it will not bend anymore, the force goes down a tad, then Snappy Gator.
So we do not know if the bolt was deformed before or after the fall.
One thing, welding a complete 360 weld on a part that small will really heat it up.
If it were held in a metal jig, there could be a heat soak right at that point, causing a differential in metalic properties.
Also, if you use this as a ceiling hanger, the eye should be oriented so that a load will be placed in line with the vertical axis.
If you look at the Petzl link, full props stevep, you will see this is what they have done.
We could look at the Modulus of Elasticity for Ti alloy, that might be cool.
The reason they do not make Ti Biners is because the alloy does not like to be bent that much.
I think the only way to build this Ti bolt would be to increase the Net Dia., add bumps instead of grooves to hold the glue, put the eye on the C/L, machine the part or find a welder from the Nasa program.
One last thing, when you weld a closed loop like that, there is no expansion joint.
I went through this back in 84 when they had a recall on Ritchey Bull Moose Alloy handlebars.
They were way cool, I wish I could find a set.
The stem, and bar were one, complete with brake hanger.
But there was an equi lateral triangle of welded, heat treated alloy.
And they cracked like a Mo.
OK, I'm Out.
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Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
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Dr. Schlock - please give it a rest already...
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Russ Walling
Social climber
Out on the sand.... man.....
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zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
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Dr. Rock
Ice climber
Castle Rock
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Eureka!
When ceiling installed, the eye orientation will produce shaft deformation, due to a misalignment of forces, eventually leading to catastrophic failure over time due to cyclic static loading.
So although these bolts may be perfectly fine for vertical wall placement, witnessed by the many already in place, I would think twice about hanging of a Ti ceiling bolt.
The good news is that there are probably relatively few ceiling bolts of Ti compared to wall bolts?
That, I do not know.
And how do you tel steel from Ti?
Carry a magnet?
That is my final answer.
Next thread?
Next victim?
Judd, For The Defense.
Hah! Remember that one!
Then you might remember O.K. Crackaby?
And man, did Burl Ives have a crack!
But I don't think he ever smoked crack.
Charlie Daniels, maybe.
Hoyt Axton, definately, but not Burl.
Man, how would you like to be on the crux at Washington Column, and you look down and see Burl Ives on Crack, crawing up your rope with a dagger in his mouth and a gitar on his back, Ho Man!
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Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
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Dr. Rock = Drkodos.
Dirtineye nailed it.
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Dr. Rock
Ice climber
Castle Rock
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Who is the Dr Kudos, and what did I do to his wife?
You realize each time ya tool me, that it's another bump?
Ha!
Bump on, my friend, bump on...
Hey, what about a Platinum ceiling bolt?
Any ex microwave engineers around here with exit property?
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dirtineye
Trad climber
the south
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I have informed Liberty Mountain, who handle all Ushba stuff now, about this problem, and given them a link to this thread.
We will see what they have to say, if they show up.
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HMS
Trad climber
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Found the following on http://www.bolt-products.com/Glue-inBoltDesign.htm:
"There have been a number of welded eye bolts on the market but weld failures have always been seen as a problem. One on the market (not in Europe) that I know of is the USHBA bolt made from titanium, in tests by the German Alpine Association (D.A.V.) three out of five broke at the weld at under 10kN."
So, its not that strange seeing a Ushba bolt break. But this bolt broke not at the weld but at a different place/stress-zone).
I would (and do so) use only forged bolts with the shaft comming from the middle of the eye (of the bolt), which are placed with the eye countersunk. Looks like the best solution to me - least stress while in use. Do have a look at the www.bolt-products.com website - its informative and the guy(s) know what there talking about.
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stevep
Boulder climber
Salt Lake, UT
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First, Dr. Rock, Pie are not square, they are round :-).
Thanks for the input Evan. I didn't mean to take shots at the bolter, but certainly the picture does make it look like the shaft is exposed. I'm not sure I quite understand how the bolt would bend unless it either was installed with some shaft exposed, or rock/glue later crumbled/spalled away from the shaft, thus exposing it and allowing it to become a lever while people were swinging around dogging on it.
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Evan Jackson
climber
Austin, texas
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Steve, I don't know how the shaft bent either, but believe you me, the hole is still in good condition.
HMS, there is a crack located at the weld.
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dirtineye
Trad climber
the south
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HK, can you prove that he is indeed Kodos, cause although I'm fairly certain, absolute proof would be good.
Since he's more of an a$$hole than Crowley or anyone else for that matter ever was...
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HMS
Trad climber
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To Evan: Yep, its a design fault.
Designing and placing a good bolt is tougher then it seems. No bolt/system is foolproof, unfortunately. But we should try and understand the loads in real-life situations before designing bolts. Only the best is good enough - make the bolt tougher and longer than you think it has to be.
I want the bolts I place to last at least 50 years and find it really difficult to decide what to use (and yes, budget plays a role). There is not a single bolt that works in every situation. I would like to find a cheap, forged, non-flexing, visually low-profile, HCR glue-in bolt with the shaft centered to the eye(placed countersunk and 4 to 5 inch deep) and a slightly more viscose glue than the stuff I use. The Petzl Collinox/Batinox come close, apart from the cost aspect.
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JLP
Social climber
The internet
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"Steve, I don't know how the shaft bent either, but believe you me, the hole is still in good condition. "
It's a 10mm bolt in an 11mm hole. The 11mm hole will actually be larger because that's how drilling works. The wrong bit could also have been used - 1/2" is ~12.5-13mm for example. That leaves at least 1-2mm for the bolt to bend (plenty, given the photos). You'd just have to measure it. It also brings one to question what kind glue was used and how much of it. It would appear that insufficient glue is the same as not drilling deep enough. If a 1/2" bit was used, that would also allow a lot more bending because of the increased thickness of the softer glue layer.
But who cares - the ring feature is still the most interesting thing to me. It is obviously a huge weakness. If there is a cracked weld, that's more a process control issue.
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graniteclimber
Trad climber
Nowhere
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There have been a number of welded eye bolts on the market but weld failures have always been seen as a problem. One on the market (not in Europe) that I know of is the USHBA bolt made from titanium, in tests by the German Alpine Association (D.A.V.) three out of five broke at the weld at under 10kN."
Any Taco resident have any friends in the German Alpine Association? who can get a copy of the test results?
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Dr. Rock
Ice climber
Castle Rock
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Here is a more detailed explanation of the bent shaft and the failure process:
John B Breneman,CE
Prof. of Engineering,Mechanics
Penn State Univ.
So what happens here is they take a perfectly good piece of space program Titanium, then score it, then bend the hell out of it, which it does not like, then they weld the hell out of it.
How many of the original properties do you think the round stock has retained after all that drama?
Just for gits and shiggles, a hardwood bolt was sketched, Brazilian Rosewood from Souther Lumber backed up by some Napalese Ironwood, which is then epoxied to a strip of Georgia Yellow Pine for good acoustics, turns out a half inch hardwood bolt will take 25 Kn, go figure.
Here is a link to a Nasa Database.
You can spend days just on Titanium:
http://ntrs.nasa.gov/search.jsp
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