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dropped cam

Posted: Thu Jan 24, 2013 12:15 pm
by henkg
Somewhere on the forum this has been asked...

My 2nd dropped a BD yellow cam, from above the crack on Jacobs, all the way to just about the bottom. It impacted rock quite hard. I can see a slight impact mark on the face of one came lobe.

Should I retire the gear?

Re: dropped cam

Posted: Thu Jan 24, 2013 12:58 pm
by Justin
More than likely, but I would be interested to see a photo of the cam.

Re: dropped cam

Posted: Thu Jan 24, 2013 3:02 pm
by mokganjetsi
I guess the same argument as for dropped biners / QDs hold? Any reason why not?

Re: dropped cam

Posted: Thu Jan 24, 2013 4:18 pm
by NatureBoi
henkg wrote:Somewhere on the forum this has been asked...

My 2nd dropped a BD yellow cam, from above the crack on Jacobs, all the way to just about the bottom. It impacted rock quite hard. I can see a slight impact mark on the face of one came lobe.

Should I retire the gear?
retire it to me, I will use it :pig:

Re: dropped cam

Posted: Fri Jan 25, 2013 11:08 am
by Brussel
The issue is with the carabiner.

Impacts can introduce stress cracking. But I recall reading a BD test where a biner dropped off ElCap in Yosemitep (1000m) on to granite was fine so there is somewhat of a concern and I certainly would retire biners. I dropped a quick draw from 20m and actually had a small piece of rock embedded into the aluminium :)

as for the cam: the axles are steel and does not face the same issue. As long as the axels are straight and the cam actuates cleanly that should be fine. The lobes are in compression rather than tension like a biner and should be fine.

I guess the question is what is your life worth to you?
for the R800 it's probably worth buying a new one, although I'd possibly still use it dependant on what the damage looks like, how hard it hit and how far it fell etc. etc.

Re: dropped cam

Posted: Fri Jan 25, 2013 12:32 pm
by Justin
I'd still like to see a pic of the impact spot.
If you keep it then there is the chance you may be lead out above your 'dropped' cam, fighting through a crux... how will you feel about this? :cheese:

Re: dropped cam

Posted: Fri Jan 25, 2013 1:39 pm
by mattb595
K dont let this sound too weird but if you know of a radiologist you can ask them to do a scan of the cam stress cracks should show up. I did it once with my favorite atc.

Re: dropped cam

Posted: Fri Jan 25, 2013 1:58 pm
by Chris F
Send it to me and I will subject it to several years of comprehensive field testing to see if it is safe, before (eventually) returning it.

The only place where I would have big concerns about damage is the "eye" where the sling is held. Guess you could always set up a drop test with a couple of concrete slabs some spaces, a couple of G clamps, a pulley up a tree, a length of rope (disposable), a sandbag and a tree?

Re: dropped cam

Posted: Fri Jan 25, 2013 2:05 pm
by Nic Le Maitre
Here is the forum thread where micro fractures are comprehensively debunked: viewtopic.php?f=1&t=6779&p=34845

Basically the rule is this: If obvious deformation has taken place, retire it. Or if doubt exists about its safety, retire it. The fact that you are asking this question here implies that you are unsure about the safety of the piece and you should probably retire it if you are going to be unwilling to trust it in future. The bottom line is that it is probably fine but would you bet your life on it?

Re: dropped cam

Posted: Fri Jan 25, 2013 2:38 pm
by mokganjetsi
Gear is made to take impact. Imagine the forces on that cam when you take the 40ft whipper. Methinks a lot of the "uncertainty" is more linked to fear than facts; who came up with the whole "micro fissure/crack" in the first place and how come it was so readily accepted? Sure you bet your life on that cam (if its the only piece in), so make sure there's no material damage, but a dent or scratch should not render it unsafe. Maybe go place it at a sport crag; clip a bolt below it and test it to set your mind at ease?

Re: dropped cam

Posted: Fri Jan 25, 2013 3:30 pm
by shorti
I dropped a cam once. Since then I put my weight on it twice and it popped both times. Just saying... (and it's got nothing to do with the fact that it was desperate placements :mrgreen: )

Re: dropped cam

Posted: Fri Jan 25, 2013 3:39 pm
by Nic Le Maitre
mokganjetsi wrote:Gear is made to take impact. Imagine the forces on that cam when you take the 40ft whipper.
Gear and cams in particular are designed to take force in a very specific way. For cams, the idea is that force is transmitted along the stem of the to the axle where it is transferred to the lobes of the cams and then to the rock. The lobes are designed to lever themselves against the rock. If it is a good placement, then all the lobes will take some of the load and if it is a bad placement, fewer of the lobes will load, but at least two lobes have to take the force. What I'm trying to say is that the forces exerted on a cam by a lead fall are within the design parameters and are distributed across the entire cam structure not localized to a specific spot.
However, when you drop a cam you can exert a very high force on one very small point of the cam, which is not within the design parameters and may lead to the cam failing.

Re: dropped cam

Posted: Fri Jan 25, 2013 4:27 pm
by mokganjetsi
Fair comment Nic. Well, should still be useful as a christmas decoration.

Re: dropped cam

Posted: Sun Jan 27, 2013 1:32 pm
by Andy Davies
Interesting subject this. The real issue is a stress raiser which results in higher localized stresses at the tip of a crack. We have seen that on the locally machined bolts that have been breaking. Stress raisers are particularly problematic for stress corrosion cracking on stainless steels and fatigue applications on most metals. Your cam is mostly aluminium and i imagine only the aluminium was dinged, also imagine you don't leave your cam out in salty air, so lets exclude stress corrosion cracking. Fatigue cracking of metals usually requires thousands of cycles, only at very high loads will you get low cycle fatigue. I can't imagine you're taking hundreds of factor 2 falls on this one cam so fatigue is very unlikely.

I will let you lot conclude

Think about why most accidents happen? belaying, abseil or lower off end of rope etc. If you take reasonably good care of your gear you should be ok. Stress more about checking your harness, belayer and tie the end of your rope in your rope bag!

Safe climbing :-)

Re: dropped cam

Posted: Mon Jan 28, 2013 8:52 pm
by henkg
Justin, some photo's attached. My gut feeling is the gear is fine. Methinks there is a difference between a cam and a biner in the way it is loaded. And the micro fracture myth has been busted. Still, that niggling feeling in the back of my mind....

I think Joe can do with my cam...

Re: dropped cam

Posted: Tue Jan 29, 2013 9:49 am
by brianweaver
If you hadn't posted this story it would be impossible to tell that anything had happened to this cam... I would totally trust it, granted I'm a bit of a nutcase...

Re: dropped cam

Posted: Tue Jan 29, 2013 9:51 am
by Andy Davies
Sjoe that ding looks epic! I think I need to have a closer look at it and test it out. The testing may take some time and I'm not too sure when I will be able to give it back :alien:

Re: dropped cam

Posted: Tue Jan 29, 2013 10:08 am
by pierre.joubert
If you added that ding to my yellow cam you wouldn't notice it under normal wear from climbing.

Re: dropped cam

Posted: Tue Jan 29, 2013 10:39 am
by Marshall1
Replace if you can, but rather a semi-dodge cam than no-cam...if you can't.

Re: dropped cam

Posted: Tue Jan 29, 2013 10:42 am
by henkg
brianweaver wrote:If you hadn't posted this story it would be impossible to tell that anything had happened to this cam... I would totally trust it, granted I'm a bit of a nutcase...

Just goes to show what you don't know about second hand gear ....

Re: dropped cam

Posted: Tue Jan 29, 2013 10:48 am
by Nic Le Maitre
You say your second dropped it? Well then they are now the proud owners of the cam and they get you a new one...

Re: dropped cam

Posted: Tue Jan 29, 2013 12:48 pm
by Chris F
Andy Davies wrote: I think I need to have a closer look at it and test it out. The testing may take some time and I'm not too sure when I will be able to give it back :alien:
I had first dibs on "testing"!

Seriously, that looks in better state than all of my cams, and I haven't dropped any.

Re: dropped cam

Posted: Thu Jan 31, 2013 2:30 am
by Captain Haddock
How about testing the rock for damage :lol:

Re: dropped cam

Posted: Thu Jan 31, 2013 12:02 pm
by Justin
Thanks for the pics Henk... Me personally: I'd carry on using that cam after giving it a pull test.
Captain Haddock raises a good point :P

Re: dropped cam

Posted: Thu Jan 31, 2013 12:31 pm
by Rastaman
How far did it fall in meters?

Re: dropped cam

Posted: Thu Jan 31, 2013 7:16 pm
by henkg
I would say 20-30 m.

Re: dropped cam

Posted: Fri Feb 01, 2013 9:24 am
by Rastaman
30m is pretty far.
Personally I would retire it for safety sake and piece of mind.
Nothing worse then not trusting gear 100%.
If your 2nd has offered to replace it (which he should have) maybe go 50/50 on a new unit.

Its a good point about the risk of second hand gear.
You have no idea whats happened to it by its scratches, dings.

:afro:

Re: dropped cam

Posted: Fri Feb 01, 2013 10:35 am
by Albert
From the pic's your piece looks in a healthy state! It's all relative and case specific, but if you feel that after close inspection you'd rather discard it, I'm sure there'll be someone out there who'll put many miles on it still..

I dropped my hand ascender from Hillbrow Tower 216m onto tar road back in 2005, picked it up, inspected it and have jumarred many safe meters with it since.