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MisterE
Social climber
Across Town From Easy Street
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Topic Author's Original Post - Apr 5, 2010 - 07:26pm PT
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Specifically, the #1 and #2
.
I overheard a conversation this last weekend about an interesting problem with these units - here's how the scenario plays out:
The units are fine in horizontal placements, and proper placements in vertical cracks, the problem arises when the cams are set in a position perpendicular to the vertical crack, such as a pin-scar, and subsequently loaded(as from a fall).
If one looks closely at the unit above, one may notice how the trigger wires are locked on a rigid trigger mechanism, and that the whole set-up is well within a reasonable flex-range of the camming unit. The unfortunate effect of this set-up *can be* that as the unit bends under impact, it can actually retract the top lobes of the cam like you were pulling the trigger with your finger on the top, causing a release of the top two lobes.
The other thing I immediately thought of is this: if one were to place the cam correctly (in a downward position), but then put a short draw on the cam (never a good idea generally), the motion of the rope could re-set the cam in that perpendicular fashion. I have seen it many times with other cams. The way to avoid this is to use looser and longer runners, rather than "dog-bones" on the cams.
Now look at the Black Diamond C3:
BD was able to avoid this problem in two ways:
1. the trigger wires are internal, reducing wire movement during loading, and
2. a more flexible trigger would reasonably seem to allow a bit of movement in the trigger to keep it in the same line as the cam lobes during loading.
Additionally, as a 3-cam unit, it will respond differently to loading.
I would be interested to hear how folks feel about this as an issue.
I felt like it was worthy of discussion.
Erik
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MisterE
Social climber
Across Town From Easy Street
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Topic Author's Reply - Apr 5, 2010 - 07:31pm PT
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SteveW
Trad climber
The state of confusion
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I'm all for the camalots, MisterE!
Great find--thanks!!!!
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Footloose
Trad climber
Lake Tahoe
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Thanks for the heads-up. I have em.
When I get home, I'll be sure to check
it out.
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bluering
Trad climber
Santa Clara, Ca.
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I can see what you're saying, but these aren't ideal 'pinscar' cams, right? Offsets would be better.
It is a good heads up, though. I've gotta check one out, never touched one.
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MisterE
Social climber
Across Town From Easy Street
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Topic Author's Reply - Apr 5, 2010 - 08:07pm PT
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DMT: So funny - I got to page 3 of the same thread before I got cooked.
I did learn there are horizontal placement issues as well, though.
Thanks for the link - RC.noob scares me...
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adatesman
Trad climber
philadelphia, pa
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Most likely those videos are mine, and best bet is to scroll to somewhere near the end of the RC thread where I posted the results of my offline discussions with Metolius.
Short version:
1. the lobe retraction pretty much went away once the fixture was reinforced. It was still possible to get it to happen, but was very, very dependent on spacing between the plates and depth of cam insertion (took me an hour to get it to happen after reinforcing it).
2. I only ever got one of the inner lobes to retract, which essentially leaves you with a 3 lobe cam. There's no particular reason why you need 4 lobes (TCU's work), so no big deal there.
3. Having seen a large amount of Metolius' in-house only documentation I have absolute faith that they looked into this quite thoroughly and found it not to be an issue.
4. IIRC, I edited the videos (they're on YouTube) to reflect all this a while ago, so hopefully anyone who finds them at this point will have all that information.
-a.
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mucci
Trad climber
The pitch of Bagalaar above you
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I have a #1 and #2, barely used.
Will trade for aliens.
Mucci
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healyje
Trad climber
Portland, Oregon
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From page 8 of the RC.com thread referenced in the previous post above:
July 9th, 2009 - Metolius Climbing wrote:
It is our understanding that this forum is intended to be a venue for discussion by individual climbers. We feel it is generally inappropriate for us as a manufacturer to participate. Manufacturers, retailers, organizations (such as AAC), and guides are all great resources that can be contacted directly. When you contact us with a question about our gear, we will work with you one on one to provide answers. However, the moderator asked us to comment on this thread, so we are making an exception. To contact us directly, go to metoliusclimbing.com. You can call to talk to a live body, or send in a letter, and we will respond as soon as we can.
We would like to start by thanking everyone that contributed to this discussion. One of our main goals has always been to get climbers to look critically at all the gear they use. Every piece of gear has design limitations. Every piece of gear is subject to misuse, and every piece of gear can fail well below its rated strength. It is critical to personally analyze and inspect every piece of gear you use and understand its limitations. You cannot leave this up to someone else.
The ideal cam would have a trigger that would disappear after placement, to avoid accidental triggering of the cam lobes. While this is not possible, we feel we have used the best option for a flexible body, single stem cam.
When we first saw the images of our cam moving in the fixture during the horizontal test, we suspected there could be a problem with the test. We do horizontal pull testing as one of our standard tests, and have never seen this problem. However, we immediately attempted to duplicate the result we had seen in the video. We were unable to get the cam lobe to retract as it appeared to do in the video. Then we began looking more closely at the video, and noticed that the fixture was moving. We contacted the tester and informed them of the fixture problem. The tester agreed with us and created a new fixture that would not move. With the new solid test fixture, the tester was unable to duplicate the initial negative result. No problem, Mystery solved.
We would like to encourage the tester to keep testing, keep busting gear, and keep posting, but be a little more prudent about getting confirmation from another tester prior to releasing results. One positive thing these tests indicate is that cams don’t seem to work very well in expanding cracks. We will try to duplicate this expanding crack test, something we have never been able to do before.
There is also an image of a person holding a Master Cam head in one hand and bending the stem 180 degrees in an effort to demonstrate the trigger pulling on the cam lobes. We have been unable to reproduce this effect in any placement in the field. The tester was also unable to produce this effect in the horizontal test set up. The key to performing this trick is that the cam lobes have to be fully extended so there is no slack in the trigger cords. In any viable placement, the cam lobes must be in some degree of retraction, which creates slack in the trigger cords, which makes it all but impossible for them to pull on the cam lobes. We specifically chose a Kevlar core, nylon sheath trigger cord because it does such a good job of isolating the trigger mechanism, and allowing independent movement of each cam lobe.
I mentioned earlier that we do a horizontal placement test as one of our standard tests. This is not a standard UIAA test, but we plan to present it for discussion and consideration at the next UIAA safety committee meeting.
I would also like to mention that we do an off angle test, to try to evaluate a cams performance in a bottoming crack. In this test the cam is plugged straight into a crack fixture, and blocked from rotating and aligning itself with the direction of pull. The initial test results indicate that the cams performance becomes very unpredictable when loaded like this. We will continue to refine this test in hopes of getting a more consistent result, but preliminary results indicate that this should only be a placement of last resort, and should not be expected to hold a serious fall.
Thanks to all who have participated in this discussion, and thanks to the moderator for inviting us to contribute.
Doug Phillips
President Metolius Climbing
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F10
Trad climber
e350 / Bishop
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Eric, thanks for taking the time to post up the concerns with this issue,
James
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Mungeclimber
Trad climber
sorry, just posting out loud.
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is the Metolius post saying that expando = maybe bad for their cams? If and only if that is what they are implying, then that is all she wrote for the BW market.
will reread later tonight.
and check in on the 'purchase cch' thread. clearly needed.
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MisterE
Social climber
Across Town From Easy Street
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Topic Author's Reply - Apr 5, 2010 - 08:48pm PT
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The only time it seems it could happen is in an almost tipped-out placement. I could see how flaring pin-scars might be a concern as well.
Thanks for posting the reference Joseph.
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Slakkey
Big Wall climber
From Back to Big Wall Baby
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One could spend a lot of time effort and even money trying to prove fault with just about every piece of climbing equipment. Under certain circumstances anything has the ability to fail. Not only is there risk in climbing there also exists some risk in the equipment as well. Pretty soon people will have us climbing with nothing other than hexes and nuts again and probably find fault here too. Its all sort of a moot point until it actually happens personally to you.
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Mark Hudon
Trad climber
Hood River, OR
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So let me get this straight, MisterE posted this today, April 10th 2010 yet Metolius replied to the problem on July 9th of last year?
Is this a news thread or history thread?
Seems to me to be a much ado about nothing thread.
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adatesman
Trad climber
philadelphia, pa
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@Munge- I was the guy who did the testing mentioned above and the expando thing did come up in my discussions w/ Metolius. IIRC they said it was something they'd look into as it wasn't a case they'd looked at previously, but I don't if anything came of it...
-a.
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MisterE
Social climber
Across Town From Easy Street
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Topic Author's Reply - Apr 5, 2010 - 09:21pm PT
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Sorry Mark - I did a search for it here and came up empty.
I just never go to RC. com, as I stated earlier.
I love Metolius' products, this wasn't meant as a deprecation of their product, just something that came up.
I feel a bit foolish for starting this, in retrospect. I guess i need to "get out" in the internet world more or something.
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G_Gnome
Trad climber
In the mountains... somewhere...
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Attention whore?
Sorry Eric.
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F10
Trad climber
e350 / Bishop
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I will take some of the blame for this thread. Some one pointed this out to me and I was just passing this along as something to watch out for.
I showed this potential problem to Eric over the weekend and he felt that it should be brought out into the public forum. I agreed, however I prefer to just sit back and "surf the web"
Eric, thanks for taking others safety into concern,
James
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ontheedgeandscaredtodeath
Trad climber
San Francisco, Ca
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I appreciate the post-- I like these cams and had heard about the horizontal thing somewhere. Nice to have the issue seemingly and summarily resolved.
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Andrew F
Trad climber
Sunnyvale, CA
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I followed the thread on rc.com when it was around, and was never fully satisfied with the response from Metolius. I agree that Aric's testing was flawed. But you can easily demonstrate problem using one of Metolius's own hangboards: place an orange Master Cam horizontally in the biggest edge hold of a Simulator. This is a pretty good placement as the lobes are contracted almost all the way (green dots on the rangefinder) and the edge is realistic of a normal horizontal placement. You can easily make the inner lobes retract by just bending the stem down. The cam will then pull out until the trigger mechanism shifts and unloads the kevlar wires.
If you repeat the same test, but first push the trigger mechanism back up the stem so that the kevlar wires are artificially forced to be slack (removing any pulling effect from the trigger), you can't reproduce the same effect.
It's pretty obvious if you look at the trigger mechanism for a few moments how the trigger could be pulled in a real placement this way. This doesn't happen with Camalots etc because the trigger mechanism has much more freedom to move whereas on the master cams it's forced to bend with the stem.
I love mine but try to avoid using them in horizontal placements for this exact reason.
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Mark Hudon
Trad climber
Hood River, OR
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Naw, don't worry about it MisterE, the internet is too wild and wooly to be tamed and understood!
All in all, I'm thankful for the whole post, I learned something about my gear and can be more thoughtful about placing it next time.
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bluering
Trad climber
Santa Clara, Ca.
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I love mine but try to avoid using them in horizontal placements for this exact reason.
I thoughts that's why you ALWAYS carry some tri-cams. That's why I do. Awesome in hozirontals. I'll place a cam, but only if my tri-cams don't fit.
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Rankin
climber
North Carolina
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Master Cams are bomber. I have placed them in plenty of different placements and have had no issues whatsoever. Glad people test this stuff, because I just climb with it.
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blr
climber
socal
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A little off topic, but one thing that I think the master cams have done better than the aliens is the trigger wire. Specifically the flexibility of the trigger wire.
If you retract a master cam, pinch a pair of cam lobes with your finger and let the other two go, you'll see that they are free to expand it's entire range. The stiffness/stickiness of the alien's trigger wires only let the other lobes expand a fraction of it's range. I think this could actually make the regular master cams better for flaring placements than the regular aliens. Still like my aliens though.
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couchmaster
climber
pdx
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E -I tried to duplicate that issue, but was unable to do so. I'm not saying someone couldn't get it to occur, but it ain't me.
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msiddens
Trad climber
Mountain View
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Love mine and thanks for the dialog
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tomtom
Social climber
Seattle, Wa
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If you use these cams, you could die.
Think about it.
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mark miller
Social climber
Reno
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A similar thing results with almost every camming unit if knott placed properly... The inside lobes get torked up and your left with what ever nature or your destiny gives you on the remaining 2 outside readjusted lobes. that's life in the fast lane....I still place most of my cams like Knutts and my followers hate me ( long reach and you have to pay attention or you will knott be able to get it out). I see so many climbers rely on the camming advantage that it makes me up set.
Sometimes if that's all you got, it's better then a talk with your almighty....but to place cams inconsiderately and hope they will hold every-time is beyond wreck-less "Folly". I'm still an Alien fan but I do carry Metolius "Small" units as work horses on every pitch.
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monkeyboyrob
climber
military industrial complex, virginia
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Aug 12, 2011 - 12:49am PT
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i know this is a year old thread, but...
i just popped one of the rc.com links, and holy shiznit! that's beating it into the dirt!
ackk!
well, at least it was thirty two pages of quotes and speculation to one page of bickering.
now that i have also not contributed anything, i am prepared to return to that thread...
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Scole
Trad climber
San Diego
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Remember when sex was safe, and climbing was dangerous? Climbing is still dangerous. Place the gear correctly, within it's limitations, and climb within your limitations and it might be OK: Then again; it might not.
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