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Gear failure

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,648
OAW wrote:So Holyshootdude it looks like you have learned your lesson on hear. I could be wrong, but no one who has commented is a climbing gear inventor or engineer.
Well, here it is from an Engineer: The only possible way that cam failed in the way shown in the photo is that it inverted. The only way that a cam can invert is if the placement is bad, this doesn't necessarily mean that the placement had to look bad, but the fact that it inverted means that it was bad. If the placement looked good it means that the crack expanded alowing the piece to invert, but I'm going to guess (based on the OP's limited discription) that the cam moved from it's original placement into a bad position prior to being weighted and inverting.
Reggie Pawle · · Boston, MA · Joined Nov 2010 · Points: 5
OAW wrote:The best way your are going to get answers is to have your friend who failed it write up a detailed summary of what happened and send it off to Fixe so they can analyse it and recreate the event.
Probably a good idea anyway, but it's worth noting that Fixe didn't make this cam as it's 4 years old.
Greg D · · Here · Joined Apr 2006 · Points: 883

I'm alway surprised when people are surprised that an Alien failed. I get surprised a lot regarding Aliens.

Matt N · · Unknown Hometown · Joined Oct 2010 · Points: 415
Noah Haber · · Unknown Hometown · Joined Aug 2010 · Points: 78
JLP wrote:What a waste. That Alien looks like it hasn't yet seen a full wknd of climbing. FS: Old car, low miles, driven by granny to church and back...then crashed in a ditch.
Post on MP.com: "ditch failure"
slim · · Unknown Hometown · Joined Dec 2004 · Points: 1,103

post should be retitled "user failure".

Cor · · Sandbagging since 1989 · Joined Mar 2006 · Points: 1,445

Is it me seeing things, or is all that is broken is the trigger wires???

Matt N · · Unknown Hometown · Joined Oct 2010 · Points: 415
Holyshootdude wrote:The placement was good .. It was body weight ..
That's a bit contradictory.
rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526
Holyshootdude wrote:The placement was good .. It was body weight
No, it was body weight AFTER two or three short falls, each of which is quite capable of moving the cam or perhaps expanding the crack of a flake was involved.

Holyshootdude wrote:Just try to believe the cam was good and failed or I wouldn't of posted this.
As a number of people have said, this is an umbrella failure. There is no evidence of gouging of the cams, and the axle hasn't bent at all. Umbrella failures are caused by the cam being tipped out. However good the cam might have been at the time it was placed, by the time it was just hung on it had shifted and was no good. In the somewhat harsh world of accident analysis, that qualifies as user error, but the problem is that with small cams, there is very little margin between "good" and "tipped," and a very small shift could change one placement to the other.

The lesson to be extracted from this is that cams that hold falls have to be reinspected and sometimes replaced before they can be loaded again.

Aliens have had their problems, but this is primarily a placement error, not an Alien defect. However, it is true that other manufacturers have machined stops into their cams to prevent cam inversion. Such a cam, even if tipped in, might have held bodyweight.
divnamite · · New York, NY · Joined Aug 2007 · Points: 90
rgold wrote:However, it is true that other manufacturers have machined stops into their cams to prevent cam inversion. Such a cam, even if tipped in, might have held bodyweight.
RG, which company currently makes single axle cam with cam stop? I know Metolius TCU has cam stops and single axle, but I heard it's not useful. Just wondering out loud.

I don't have my old aliens in front of me. Yellow alien is the same size of C4 .4, correct?
Noah Haber · · Unknown Hometown · Joined Aug 2010 · Points: 78

WC heliums have cam stops. Edit: as do c3s.

Optimistic · · New Paltz · Joined Aug 2007 · Points: 450

Kind of off-topic, but as noted above, my C3's do have cam stops...and the BD website say says not to use them "open", ie in such a way that the cam stops would be loaded, like you can supposedly do with a C4. Doesn't that kind of make the C3 cam stops a waste of metal and (a tiny amount of) weight? Is anyone aware of any strength testing done on C3 (or other) cam stops?

Larry S · · Easton, PA · Joined May 2010 · Points: 872
kennoyce wrote: Well, here it is from an Engineer: The only possible way that cam failed in the way shown in the photo is that it inverted. The only way that a cam can invert is if the placement is bad, this doesn't necessarily mean that the placement had to look bad, but the fact that it inverted means that it was bad. If the placement looked good it means that the crack expanded alowing the piece to invert, but I'm going to guess (based on the OP's limited discription) that the cam moved from it's original placement into a bad position prior to being weighted and inverting.
I agree w/ the above. Somehow the lobes on at least one side umbrella'd. They aren't designed to hold a load in that situation. My guess is the axle is still straight, the lobes still move, but the trigger wires broke. Repair the trigger wires and the cam should be usable again.
Larry S · · Easton, PA · Joined May 2010 · Points: 872
divnamite wrote: RG, which company currently makes single axle cam with cam stop? I know Metolius TCU has cam stops and single axle, but I heard it's not useful. Just wondering out loud. I don't have my old aliens in front of me. Yellow alien is the same size of C4 .4, correct?
TCU's can still have their heads invert. C3's won't because of the design of the head/axle.
divnamite · · New York, NY · Joined Aug 2007 · Points: 90
Optimistic wrote:Kind of off-topic, but as noted above, my C3's do have cam stops...and the BD website say says not to use them "open", ie in such a way that the cam stops would be loaded, like you can supposedly do with a C4. Doesn't that kind of make the C3 cam stops a waste of metal and (a tiny amount of) weight? Is anyone aware of any strength testing done on C3 (or other) cam stops?
I was told once by a rep that only double axle design can be use as a "nut" placement.

Larry S wrote: TCU's can still have their heads invert. C3's won't because of the design of the head/axle.
I'm aware of TCU's issue. I can see C3 might not have this problem because the way the lobes stack against each other.

If a yellow alien is the same size as a C4 .4, that's a pretty decent size cam to mess up.
Allen Corneau · · Houston, TX · Joined May 2008 · Points: 80
divnamite wrote: I was told once by a rep that only double axle design can be use as a "nut" placement.
You were mis-informed.

As mentioned up-thread, WC Helium Friends have rated cam stops from 11kN and higher. For comparison, most smaller nuts are only in the 6-10kN range.
Jason Lantz · · Centennial, CO · Joined Sep 2008 · Points: 170

a) bad placement....
b) cam stops on single axles should be not be considered structural with regard to withstanding a force...
c) RG is always right...
d) when RG is wrong see letter c.....

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065
Jason Lantz wrote:a) b) cam stops on single axles should be not be considered structural with regard to withstanding a force
WC zeros, helium friends, DMM 3/4 CU, DMM Demons ...

climb enough and youll encounter internally flaring cracks without much constrictions ... hexes and tricams would be ideal but few people carry those on lead anymore ... a passively rated cam is you next best bet ...

;)
mattm · · TX · Joined Jun 2006 · Points: 1,885
bearbreeder wrote: climb enough and youll encounter internally flaring cracks without much constrictions ... hexes and tricams would be ideal but few people carry those on lead anymore ... a passively rated cam is you next best bet ... ;)
Man is that the truth. Those cracks (I remember them at both Squamish and Index) were always a challenge to protect. I remember one where a BD.5 was the PERFECT size at the edge but as soon as you got it in it would completely open up. A .75 was able to fit (BARELY) and then opened up to a just an ok placement. Ideal would've been a 1 but you couldn't get the thing in! TriCams can be funky in vertical, inward flares but are the cat's meow in horizontal, inward flares.
teece303 · · Highlands Ranch, CO · Joined Dec 2012 · Points: 596

C4s can indeed be used as a "nut placement." Contract them 0% and support both sides of the lobes with a good shelf of rock.

I've never done this, because I've never run across a spot where this placement made sense, and it scares me. But it is listed as OK in the pamphlet that comes with a C4. (And it was true of the previous generation, too).

Personally, I love how the #00 TCU goes from: 1) the lobes are going to shear, to 2) perfect placement, to 3) you're never getting that cam back, all in the course if 1/4" of throw on the trigger.

Guideline #1: Don't be a jerk.

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