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Chockstone Forum - Accidents & Injuries

Report Accidents and Injuries

 Page 3 of 9. Messages 1 to 20 | 21 to 40 | 41 to 60 | 61 to 80 | 81 to 100 | 101 to 120 | 121 to 140 | 141 to 160 | 161 to 174
Author
biner breaks on Forever Young

Miguel75
9/12/2011
8:56:59 PM
People are responsible for their own choices when it comes to clipping gear or bolts. I'm glad no-one was hurt in this incident and don't really see the need for personal attacks. Neil owned his mistake.

"No more fighting now I mean it! Anybody want a peenut?"

benjenga
9/12/2011
9:03:18 PM
Hey I was thinking, it may seem simple but how about when ever you place a U you glue it with a spare length of bar or a thick scewgate in the notch as a spacer to avoid this problem. Remove the bar when you move on to the next U??
mikllaw
10/12/2011
7:02:27 AM
On 9/12/2011 TonyB wrote:
>Mike,
>Even at 2/3 strength, a fall like that shouldn't have produced anywhere
>near enough load to break it, shouldn't it ?

it's LOST 2/3rds (or maybe 7/8ths) of its strength, anyway it lost enough to break.

The belay was probably a 'hard' catch; as the climber had decided he couldn't make the clip and went down to jump off, his belayer proabably took in and locked off.

salty crag
10/12/2011
8:42:49 AM
Its highlighted to me I need to change my perception when climbing sport routes. I climb 90% trad and tend to relax and rather blindly clip and go when on the occasional sport climb. Going to add couple of extra slings to the rack from now on.
ben wiessner
10/12/2011
9:15:52 AM
On 10/12/2011 mikllaw wrote:
>it's LOST 2/3rds (or maybe 7/8ths) of its strength, anyway it lost enough to break.
>
>The belay was probably a 'hard' catch; as the climber had decided he couldn't
>make the clip and went down to jump off, his belayer proabably took in
>and locked off.

Mike you're barking up the wrong tree. If this was the case, then why did Rob mention in his post that he "felt absolutely no take in the rope as I heard the snap"? I think Rob has already helped clarify what happened in his earlier post, but I'll have a go now too. Otherwise we're going to learn nothing, regardless of how much speculation takes place.

The fact that seems to be getting forgotten was that the positon of the biner. To state the obvious, when a draw is normally attached to a ring, the top biner sits below the ring, flush to the wall. When Rob fell the top biner was not in this position, and it couldn't rotate into this position, due to the ring being too tight to allow gravity to pull it down.

I'll try to explain with more detail what happened. I noticed as Rob was climbing past the 3rd draw that he brushed up against it, resulting in the top biner being flipped upside down (so that it was now sitting _above_ the bolt) and twisted slightly, so that the nose of the biner was in contact with the rock. As Rob moved past the draw the top biner did not fall back into the normal orientation (because the bolt was too tight to allow this to happen), instead stayed upside down. And then, when he fell with the biner in this position, the biner was loaded in a way it was not designed to be loaded ie the nose of the biner was forced back towards the spine of the biner.

I'm no engineer so I don't have the ability to use more descriptive terminology, but I hope that helps clarify.

(NB Although I noticed the biner sitting at an unusual orientation when Rob was climbing above it, I didn't think of alerting him to it, because I never thought that the biner could break if he was to fall. Now I know better!)
Dr Nick
10/12/2011
10:43:04 AM
Another thing to consider is the profile of the krab. That one is a T-section rather than the traditional oval. I'm going to make a wild assumption and say that makes it more prone to catching in a tight spot like that, since there's a thin section that can lock in the bottom of the ring.

Take home message is to always have a think about how loads might end up being transmitted to your gear.
TonyB
10/12/2011
1:04:37 PM
On 10/12/2011 ben wiessner wrote:
And then, when he fell with the
>biner in this position, the biner was loaded in a way it was not designed
>to be loaded ie the nose of the biner was forced back towards the spine
>of the biner.

Sounds like a failure in torsion. Any mechanical engineers here keen to do the sums ?
mikllaw
10/12/2011
5:31:17 PM
On 10/12/2011 ben wiessner wrote:

>The fact that seems to be getting forgotten was that the positon of the
>biner.

Draw a picture?
If anyone wants to help me I can place a mess of oversunk Ubolts and we can test a few biners

JamesMc
10/12/2011
5:48:52 PM
Sounds like bending rather than torsion, ie opposite to the krab straightening out. An inspection of the real victim ( the krab) would confirm.
rolsen1
10/12/2011
8:01:14 PM
On 10/12/2011 mikllaw wrote:
>On 10/12/2011 ben wiessner wrote:
>
>>The fact that seems to be getting forgotten was that the positon of the
>>biner.
>
>Draw a picture?
>If anyone wants to help me I can place a mess of oversunk Ubolts and we
>can test a few biners

Well testing would be the way to find out the truth....... either that or just taking the opposite position to whatever Muki/Jammin/Bomber Pro says, which is quicker, easier and probably just as effective.
One Day Hero
10/12/2011
8:35:07 PM
I actually agree with TonyB here (for the first time ever!). My uninformed guess is torsion fail as the biner was trapped in a 'sticking out from the wall position'. Spine was torqued downwards as the load came on, twist, snap, etc.

No need for testing, just don't push the bolts in so flush with the rock (this is pretty obvious to everyone except arty-type bolters). Neil used to be a pretty amusing and eccentric bolter but is now far more boring, so there's no tut-tutting required.

nmonteith
10/12/2011
8:40:25 PM
On 9/12/2011 benjenga wrote:
>Hey I was thinking, it may seem simple but how about when ever you place
>a U you glue it with a spare length of bar or a thick scewgate in the notch
>as a spacer to avoid this problem. Remove the bar when you move on to the
>next U??

Great idea Ben. I've got a super chunky screwgate which would be perfect for this.

IdratherbeclimbingM9
10/12/2011
8:42:53 PM
On 10/12/2011 One Day Hero wrote:
>I actually agree with TonyB here (for the first time ever!). My uninformed guess is torsion fail as the biner was trapped in a 'sticking out from the wall position'. Spine was torqued downwards as the load came on, twist, snap, etc.

>No need for testing, just don't push the bolts in so flush with the rock (this is pretty obvious to everyone except arty-type bolters). Neil used to be a pretty amusing and eccentric bolter but is now far more boring, so there's no tut-tutting required.

>Probably no need to replace the bolts either, just chisel out some of the rock from between the legs to give the biner more room


Don't tell 'em that ODH. How am I ever going to flog my old 'full circle diameter' krabs (when I have finished with them), unless the young punters develop a fear of these newfangled lightweight krabs with spines!
Ga Ga
10/12/2011
9:02:20 PM
On 9/12/2011 benjenga wrote:
>Hey I was thinking, it may seem simple but how about when ever you place
>a U you glue it with a spare length of bar or a thick scewgate in the notch
>as a spacer to avoid this problem. Remove the bar when you move on to the
>next U??

This is what I do every time I sink a u bolt or fixed hanger.
pretty much standard practice to check how the crab will sit when clipped.
anything else would be irresponsible surely.
robby
10/12/2011
11:08:43 PM
The whole point of posting this was to make people aware of this bolt and bolts like it, also to have an experienced bolter fix it(which I would love to do, but dont have the bolting exp. required) thanks KP. I think alot of people posting havent read closely how Ben and I explained what happened, it wasnt how the crab was sitting initially, because it was sitting fine when I clipped it and indicated no danger when clipped ITS WHAT HAPPENED AFTER ON THE CRUX WHEN IT WAS TO LATE TO DO ANYTHING ABOUT IT and the biner was not faulty, I didnt clip it wrong, and ben gave a perfect catch as he always does. Its easy to say what you think we should have done at the time but there was nothing suspicious and I truly believe this could have happened to any of you. next time I head up there i will put the biner exactly how it was when I fell on it so there is no confusion. NM keep doing what your doing. KP thanks for saying you'll fix it. that was the point of this post. and to others (not all) stop the sensless arguing.

stugang
10/12/2011
11:57:03 PM
Just because the incident happened to you doesn't mean that you own it. To me it seemed as if there was a constructive conversation happening, about fixing this bolt as well as offering suggestions as to make sure it doesn't happen in the future. All good stuff, so don't know what you're whinging about.
TonyB
11/12/2011
6:27:53 AM
On 10/12/2011 One Day Hero wrote:
>I actually agree with TonyB here (for the first time ever!).

I actually must be wrong (for the first time ever!).. No mechanical engineers here to verify it ?
pecheur
11/12/2011
8:10:45 AM
On 10/12/2011 useful wrote:
>Just because the incident happened to you doesn't mean that you own it.
>To me it seemed as if there was a constructive conversation happening,
>about fixing this bolt as well as offering suggestions as to make sure
>it doesn't happen in the future. All good stuff, so don't know what you're
>whinging about.
>
I agree with this, especially as it seems that Neil, who from my limited experience generally does a good job, has added a QA step to his bolting process to ensure that this doesn't happen again. Maybe a serendipitous outcome from the warning from what Robby is saying, but surely a good thing.
pecheur
11/12/2011
8:19:09 AM
On 11/12/2011 TonyB wrote:
>On 10/12/2011 One Day Hero wrote:
>>I actually agree with TonyB here (for the first time ever!).
>
>I actually must be wrong (for the first time ever!).. No mechanical engineers
>here to verify it ?

Looking at where the biner failed on the narrow side it really does look like it was torsion, failure in bending would most likely have occurred most likely on the long side. In this case, narrow side caught and captive, the long side with the rope on the other end acted as the lever arm causing torque just before the corner.

Need a close up of the failed area to confirm.

PS Yes I'm a mechanical engineer.

Climboholic
12/12/2011
9:34:20 AM
I am also an engineer and I think people are making too many assumptions to come up with a reliable explanation of what happened. A failure like this could have serious consequences and it is worth while figuring out the facts.

The anecdotal evidence from the climber that there was “absolutely no take in the rope when I heard a snap” is completely unreliable. Firstly, this is physically impossible (and if a very low load there is more going on than just torsional failure). Secondly, the failure would be almost instantaneous so the climber wouldn’t notice (spline looks like brittle fracture (btw, how cold was it?)). Thirdly, there is too much going on in a fall for the climbers account to be reliable anyway.

From the photo there are clearly 2 failure surfaces; one on the main bulk and the other on the spline. This could be consistent with torsion failure but possibly also with fatigue if there are striations. We could tell better if there was a close up picture of the failure.

The point made by pecheur that it wasn’t bending failure because of where it broke isn’t necessarily correct. I’ve tested biners to failure with design load (bending) and they’ve broken in the same place. Fatigue is possible if the biner had an indentation from a heavy fall on a fixed hangar which could act as a crack nucleation point.

I suggest either sending the failed biner back to the manufacturer or sending it to someone like Mikl (who I believe is a Materials Engineer), to figure out exactly what happened.

 Page 3 of 9. Messages 1 to 20 | 21 to 40 | 41 to 60 | 61 to 80 | 81 to 100 | 101 to 120 | 121 to 140 | 141 to 160 | 161 to 174
There are 174 messages in this topic.

 

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