....I can break most carabiners with my fingers by pressing sideways on an open gate with my thumbs. (Okay, so I don't really "break" the carabiner but I can the the gate to move sideways enough to bypass the nose, rendering the 'biner into a weak, expensive aluminum hook). Does that mean that these carabiners are bad? I hope not! It's simply an illustartion of how a relatively minor side load can tweak an open gate. The lesson is to make sure you gates stay closed, just like the OP cam lesson is to be sure that if they can rotate that they won't rotate into a fixed position or a position of weakness.

Climb safe,

Mal

...just like the OP cam lesson is to be sure that if they can rotate that they won't rotate into a fixed position or a position of weakness.

Got the call, someone who has posted on this thread bought a link cam and wants to break it! Maybe if I just show up and provide enough alcohol I can prevent this wanton wastage of good gear? (thats my inner gear whore and childhood poverty speaking)

...and what exactly would that accomplish, if they still don't understand the forces and mechanisms that are likely involved?

i fractured my cam in a way i absolutely did not expect, very much to my surprise.

Understanding the forces involved is exactly what I'll be after - and not in a quantitative way - but rather an old school, what's-it-take-to-break-one sort of way. The mechanisms are clear both of the device and how it will be broken; no rocket science there.

I've broken lots of them over the years - from original friends on - I simply want to break one of these.

healyje, I'm with you all the way here. I love the analogies to the rigid friends. We all knew they had a weakness, yet we climbed and placed around those while advancing standards in amazing ways. We just need to remember that with all the various designs of cams available out now that we STILL need to place them with consideration for their their design limitations/advantages.

Can't wait to hear the results of your thumb test.
Mal

well, it is important to get to break what you want when you want and how you want and for no real good reason if that's what you want. i envy the true freedom with which you live your life

Blah, blah, blah....

Exactly how many cams have you broken?

What were the exact circumstances? What brands?

Pics?

In case you were wondering, I've never broken a cam, a carabiner, or any other climbing gear that I can think of, bare hands or otherwise.

Looking at the pictures of the placement, my gut feeling is that something additional happens with multiple of the lobes touching.

Let's see, two in flares just by coincidence...the Friend that blew in the downward flare in Eldo - a #4 I think that seemed more or less perfect in every way outside of a slight flare. But it absolutely disintegrated, as in all four lobes shattered into small pieces

Exactly Malcolm, but I do have a Murf-like feel about this in that it doesn't duplicate what the average climber is looking at vis a vis a fall on one in a slanted and or slanted/flaring placement.

Hmm. Coincidence?

...Frankly, I find it all a bit of an odd position to be in. Attempting to show the weakness of a cam design I fully support the marketing of. But, I'm doing it in the hope people will consider taking a bit more personal esponsibility for how they employ such gear. Because if folks can't do that, it basically means we are collectively more interested in 'foolproof' commodity products than innovative ones.

Well, it is important to get think that there is nothing to learn when you don't want to learn anything and for no real good reason if that's what you want. I envy the true freedom with which you live your life.

Clearly, there is nothing for you to learn from anyone breaking a cam but you - but then when you operate with that breathtaking air of mystique there really is nothing anyone can learn from you breaking a cam. And "more productive"? That's flat out complete bullshit.

I have seen the Kodas link before. The “paper” isn’t long and the math not “too” difficult, but previously I looked only at the first pages and blew it off only as detail in cam angle design.

I find the last two pages pretty scary. I don’t think it is intuitive, and I don’t think many people are aware of it! If I understand this properly then I am surprised we don’t see more cam failures due to this placment geometry...

If I understand this properly then I am surprised we don’t see more cam failures due to this placment geometry...

If this is as bad as it sounds, why aren't these failures happening so frequently that all are aware of the danger?

Hoo boy. It is complicated. I would think that the cams were designed with parallel placements in mind and so with the assumption that cam segments on either side would be symmetrically deployed. When this doesn't happen, there could be loads on the links and ultimately on the final arm that connects the top link to the axle that weren't anticipated in the design. (For one thing, once the links start to open up, the shape is no longer a single logarithmic spiral and so the elementary vector analysis changes.) Combine this with the higher loads resulting from flared placements and perhaps you have conditions for breakage.

That was my first reaction, too: If this is as bad as it sounds, why aren't these failures happening so frequently that all are aware of the danger? I propose two possible reasons. The first is that the maximum force occurs when the flare is the greatest angle that the cam will hold; any larger, and the cam won't stick in the crack at all (according to Kodas). So placements in flares close to this angle will be tenuous ones that climbers will avoid.

i'm going to clear up a few things with Omega Pacific first, Joseph this is that important i believe it's the responsible thing to do sorry you find that unacceptable, and felt it necessary to let loose with that speculative angst of yours

Dingus and Jay and others have already pointed out how ridiculous that one-look analysis of yours is, regarding the structural integrity of the linked lobes.

i know what intuition you're basing that on, but that's if you're comparing a segmented lobe with all pieces made of aluminum versus a one-piece aluminum lobe the Link Cam design is different, which has a steel inner link, a steel middle link, and an aluminum outer link and in the connection between the steel and the aluminum segments, the connecting flanges are two outer steel ones and one thick aluminum one in the middle the obvious design flaw you're screaming and accusing everyone else to be in denial about seems like the kind of critical design issue that would be addressed early in the cam's development process one look at this segmented cam lobe, all i can tell you is that it's likely stronger than an all aluminum segmented design, and may well have the strength comparable to a one-piece aluminum lobe, and that a lot of thought has gone into its design.

in a discussion like this, some people seem to think the more speculation there is, the better and some are way far on that extreme, who needs to not only shout out their speculation over everybody else's but also needs to demand its universal acceptance when everyone knows damn well it's just speculation it's almost psychotic. i'd rather keep the speculation minimal i personally don't think dirtme and i will be the only two ever with actual first-hand details of this kind of breakage. labs at Omega Pacific and Trango and others probably will too, at some point and with that, in time, much of the overzealous speculation would prove a total waste of time, as in unproductive

...some of you seem very adamant that the cause of failure has got to be one or the other, either the rotation and resulting leverage, or the force amplification i actually think it might well be both for example,

...so that if a cam rotates from side to side, like when the set of lobes on one side pulls out, the other set can pivot into another direction that might well have a significantly different flare profile that could be better or a lot worse, especially if the cam is jammed up against the back corner of that ellipsoid so i think it's possible that a rotation can further "amplify" a flare-induced force amplification.

...users of cams should really understand how cams work entrusting your life to a piece of gear the workings of which you don't fully understand, that's kind of crazy