[...seems a cam lobe segment can cam into the rock only when they're fully supported by the barrel of the axle, as in only when it's furled up around the axle, as in the unfurled ones behind that (an outer one) can maybe touch the rock but not cam into it.

The two, inner links on each lobe unit are built with a very new (and very expensive) process known as Metal-Injection- Molding which permits us to create detailed, precision pieces—like casting—with the strength of machined parts and are made from 17-4 aircraft stainless steel. The outer link is machined from 7000-series aluminum alloy.

Like healyje and others some here I have avoided buying link cams solely because of the perceived weakness of their jointed cams and their complexity.

I wanted to have better idea of multiplication of force due to different placement flair angles so I would have a better idea of exactly what it was I want to avoid. So here is a graph of the multiplication of force at angles from 0 to 27 degrees for a 14 degree cam angle.

[img]http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=1741;[/img]

If I understand this graph correctly...even in a 27-degree flare there appears to be only a 30 percent increase in the force.Jay

I think it would be helpful at this point for someone to estimate the possible flair angles the LST cam may have been placed at. I understand that there were other forces at play here and that it won’t be a definitive answer, but if it was likely that the placement flair exceeded 20 degrees then it should not be unexpected that the cam was broken.

Most pockets do not have sides at a constant angle (they would appear conical if they did), they are more flared in back than they are near the front, so pushing a cam in deep will engage a highly flared section rather a less flared section nearer the outside.

Sure, if forces remain close to an axis perpendicular to the axle, then yes, they will perform comparably - but, the minute those forces start to significantly diverge from the perpendicular, let alone just being applied laterally - all bets are off. That's because now we're talking about the ability of [multiple] linkage assemblies to resist deflection and deformation as opposed to that of a material.

Again, whatever the rationale you have for not being completely upfront about what happened to your cam is entirely counterproductive - you only increase speculation doling out your tidbits. The way to stop speculation is to simply state what happened in clear, concise terms.

One question though, how would negative flare affect the equations. In other words a flare at a lesser angle than parrallel.

We certainly also agree on this point, however, the loose extended segments are also capable of 'snagging' on any placement obstructions in the event of cam rotation and so present some added risk that way.

hello? that's what those cited test results showed, that the Link Cam is comparable to other cams in that latter regard. the results by Omega Pacific and Trango are limited. but that's limited evidence versus your ZERO evidence. do you have any data that support your claim that their design has got to be flawed? have you broken that cam yet? what have you learned? instead of raving about group-think and blinding consumerism and suburban life, maybe you should work on that instead

only to people with speculative angst who can't come to grips with the fact that sometimes these things take a little time (likely not much time at all in this case), to people like you who think they're entitled to everything right here and right now, so you can feed off of every bits and pieces of the latest and churn out more speculations founded or unfounded. of the tens of thousands who use this site everyday and the hundreds or more who have followed this discussion, you're the only one throwing a pissy fit over this

not overzealous? you accused everyone else who don't agree with you that they're in denial. you went against limited evidence based on your zero evidence and claim the linkages simply "have got to be" weak and thereby imply the people at that gear company are the kind who would let a design error of this magnitude make it out onto market

we're not refraining from blaming the equipment right away like you're doing because we're oh so taken by the fancy technology, as you so casually generalized. and no, we're not relying on faith alone like you want to think either. you are wrong. again, there are the cited test results. the data are limited, but not completely meaningless. that versus your zero evidence. furthermore, unlike your blind belief alone on what "ought" to be, i'm also capable of evaluating the kind of major design flaw you're suggesting and how that should bear out in field use by myself and others. Link Cams are not yet as popular and owned worldwide like some other cams are. but enough people out there do have and use them. if what you claim were true, that the joints are as flimsy as you say, at many many places you'd run into people with horror stories about how theirs have just shattered left and right. but that's not the case. more likely those people would tell you how great their range is, how they've become their "go to" pieces, or wish how they could be even lighter, or some who might say how theirs walked and got "stuck" and ended up somebody else's booty. aside from the Inspection Notice that seems to have passed, no, nothing about breakage, until this incident with a flared pod

do you understand what happens to cams in flared placements, Joseph? understand. not recite a few formula or the conclusion at the end of Vaino's formulation. not regurgitate a catch phrase or two that others have used. i'm asking because it seems if you did understand, you should at least consider that as a possible cause that should not be discounted, and be less fanatical in unilaterally declaring (with no test data of your own or from anyone else) that the linkages on the cams has got to be a design flaw. see, others and i do understand. we can therefore see a completely plausible scenario where this cam or any other cam could be broken. i'm aware that the equipment might be at fault too, by design. that is possible, though seems unlikely, after limited test results were cited and if one would simply apply a little reasoning. and i'd rather not immediately blame the equipment without at least trying to eliminate the former possibility. unlike you, i just don't believe in ignoring a possible explanation and go straight for the equipment angle and start insinuating a fault in a design that might well not be faulty, and in effect bad mouth a company that might well have not done anything wrong, who doesn't really deserve this. so again, do you really comprehend the principles described in Vaino's link or elsewhere? do you really grasp what that's about?

i can tell that you don't give a rat's ass about how what you say regarding a gear design and your unfounded speculation and claim might affect a gear company who might well have done nothing wrong. but i'm not like you. here, the caution has already been raised by the first incident. there's no real urgency for disclosure for my case. not that i haven't already given everyone a headsup, and stating clearly that more is likely forthcoming soon. i know this isn't important to you, but there is an effect on a gear company here that is significant enough to warrant consideration, and i believe it's the right thing to do in this instance to extend that consideration. all i'm doing is giving them the opportunity to see what i did to my fractured cam and see if our thinkings are along the same lines, about whether this second incident is exactly the same or nowhere near the same as what happened before. i need to talk to them about that in order to do that, when they've got the cam in hand. and they will likely need to talk to me too, as they've already said. it's like when you set up an experiment to test something, even after you've gotten the results, you still have to go back and make sure you've created the conditions correctly. others like rgold, curt, dingus, jay, k.l.k, murf, mheyman, etc, they don't seem to have a problem with this. the only one who is making this obnoxious demand is you, because you just can't come to grips that for now the basic info i've given does suffice, that me having said more is likely to come soon should suffice, that in a few days there may well be all the info anyone would want, that you seem to think your need to know everything right now should overrule everything else. well, if you still don't get it, let me tell you loud and clear. with respect to what's going on, you're just not that important, Joseph. it's nothing personal. it's just what i think is the responsible way to handle this

this discussion started by longdraw (and dirtme) is an accident report. mine is not an accident report. if it were, climber and eyewitnesses like dirtme and longdraw would usually be the best ones anyway to present what happened. and there wouldn't be any need for them to first go back and make sure that they've created the "accident conditions" correctly according to spec's on the day they've decided to be at the same place and the same time to have and to witness said accident. if you didn't realize before, i hope you will realize by now that, really, you just need to calm down

you know, it's not like i've decided to hide the fractured cam in the basement and keep its fractured coolness all to myself and have decided not to let anyone else see it ever. after the fracture, i immediately contacted Omega Pacific and express mailed it to their place in WA. i sent it ASAP to the one place that needs to have it the most, and there's now an evaluation process that goes with that that might well be quite short. sorry if Joseph on some forum discussion on the internet has to take a backseat. yeah, quite the tragedy

you should take a timeout and reconsider a little about your own behavior thus far, before crusading to alter the generalized attitudes of others who climb

I've been thinking about LCs rotating into different orientations lately. The inner lobes (assuming the outer lobes are the contacting rotation points) will slide sideways, with the smallest lobes traveling through the largest arc. This is a significant difference between traditional cam designs and the new multi-lobed units which introduces new failure modalities.

but I'd be wary of placing these cams in a way that results in asymmetric cam contact. (I think I've read about the potential for such contact as a useful feature...) Does OP have a position about such placements?

If that's all link cams are good for then I'm afriad they lose a lot of utility.

If we take the cautionaries to heart.... then the link cam should only be placed in perfectly parallel, smooth sided cracks where the stem is in perfect line with the directon of force.

If that's all link cams are good for then I'm afriad they lose a lot of utility.

Cheers
DMT

Ditto - said it before and I'll say it again, innovative design but no place on my rack for a piece of gear with such functional limitations. I've returned three of these cams to OP and now have another new red and repaired yellow in my closet... they should probably stay there.

I understand just fine, and don't need the math to explain the graph or rgolds description of the phenomena. I also don't need the math after thirty three years of climbing to know most convential cams will blow out of flares rather than break. One will on rare occasion - but the vast, overwhelming majority blow, not break.