Discussion Topic |
|
This thread has been locked |
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
Dirt - That's correct. These adhesives are mainly used to secure rebar, threaded rod, ect
into concrete. It's the threads on the rebar or rod that keeps it secure. It does knott
stick well to metal (if at all). Later versions of the Tortuga (and most likely the bolt in
question if it was purchased in 2004) have notches in them to resist lateral movement.
FWIW, a couple of the Fixe stainless steel bolts that were installed at Mickey's Beach
also rotate a slight bit; those bolts have dimples in them to resist lateral movement.
More info (my post from 2005) here:
http://www.supertopo.com/climbing/thread.html?topic_id=117902&msg=118438#msg118438
|
|
jfs
Trad climber
|
|
OK, I never post here but something's bugging me about that picture of the bolt in situ on the roof.
In the original pic of the broken bolt, the bend is AWAY from the eye. But, if I am seeing the second (roof) pic correctly(and I may not be)...it looks like the eye is hanging "below" the shaft of the bolt. I can definitely see that the shaft is sticking out from the rock too far...but shouldn't the shaft be bent in the opposite direction based on how it appears to be installed?
To put it another way, the broken bolt is shaped like a lower case letter "q" but it seems like it should have bent into a lower case "g" based on the in situ picture.
Am I missing something?
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
I've been thinking exactly the same thing. Let me repeat what I wrote in the 2nd post of this thread:
WTF?
|
|
jfs
Trad climber
|
|
That is unless...just to throw this out there and complicate things further...we are all seeing it wrong and it IS installed vertically (with the eye hanging on the right) and there's just some weird shading that makes it look like it's in at an angle. If you look closely it seems like this could be possible...???
Even if this is the case, the shaft is still exposed too much.
Potentially...years of rope dogging and lobbing off the hold outside the roof and swinging back and forth below...could have caused the stress needed? Especially if the choss broke off ONE side of the bolt only...exposing it to stress/bending in one direction only??? Or even if it was just 5 degrees off vertical???
Like HK said - a photo of the rock...
don't mind me...just trying to complicate things more. =)
|
|
Chiloe
Trad climber
Lee, NH
|
|
Here's a different photo posted on RC.com shortly after the bolt was first placed.
The way I read both this and the earlier photo, the eye is to the R, and the bolt itself
angled slightly up L (which would be consistent with the bend noted earlier).
Also, it sure looks like the shaft was already exposed.
Full context:
http://www.rockclimbing.com/photos/Sport/Hardware_was_approved.._47849.html
|
|
graniteclimber
Trad climber
Nowhere
|
|
The photo was added to rockclimbing.com on February 13, 2005 and the caption states the bolt was installed December 18, 2004, so it was already sticking out back then.
Larger version of the photo.
|
|
JLP
Social climber
The internet
|
|
" I don't think so. The bolt really should never have been loaded in the area of the groove/notch. That notch should be buried subsurface. "
The bolt is extremely weak compared to others on the market.
The glue will not prevent torsional nor tensile loading back to the ring feature.
The placement hole is larger than the bolt. Glue is soft. Therefore the bolt will bend somewhat in all cases.
Placement of the ring during the manf process may be yielding the metal, making it even weaker.
Loading the bolt in a laboratory and posting those #'s means very little.
I say the bolt is weak. I've decided I don't like it. If it were my design, I would change the ring feature.
|
|
bwancy1
Trad climber
|
|
This thread is awesome!
We have all read the posts regarding the disproportionally high number of climbers that are engineers, but who knew so many climbers are forensic metallurgists!?
|
|
Chiloe
Trad climber
Lee, NH
|
|
JLP:
The bolt is extremely weak compared to others on the market.
I claim no metallurgical expertise but ... how do you know this? Extremely weak compared to
what others on the market, in the warm marine environments for which the Tortuga bolt was designed?
|
|
Brian in SLC
Social climber
Salt Lake City, UT
|
|
Yeah, I don't know how you'd make a statement like that without knowing what the spec's on the Ti bolts were.
Speaking of which, the USHBA info on the net indicates its a special alloy? Anyone know what? Spec's?
Its a 10mm bolt with a fair amount of tensile strength, methinks. 120k or above?
-Brian in SLC
|
|
JLP
Social climber
The internet
|
|
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?
|
|
stevep
Boulder climber
Salt Lake, UT
|
|
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.
|
|
tradmanclimbs
Ice climber
Pomfert VT
|
|
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.
|
|
stevep
Boulder climber
Salt Lake, UT
|
|
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
|
|
Evan Jackson
climber
Austin, texas
|
|
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.
|
|
Dr. Rock
Ice climber
Castle Rock
|
|
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.
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
Dr. Schlock - please give it a rest already...
|
|
Russ Walling
Social climber
Out on the sand.... man.....
|
|
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
|
|
Dr. Rock
Ice climber
Castle Rock
|
|
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!
|
|
Hardman Knott
Gym climber
Muir Woods National Monument, Mill Valley, Ca
|
|
Dr. Rock = Drkodos.
Dirtineye nailed it.
|
|
|
SuperTopo on the Web
|
Let us know!