... results of tests carried out under controlled conditions.

there's a big difference between failure within design spec's and "failure" outside them. harping on and on about their cam's inherent weakness without proof, proof that may well exist beyond design specs, that's your idea of being their great proponent?

If they are moving into a decreasing volume position or across a non-uniform surface I would think there could be significant shearing forces on the lobes.

hell, the reason it took 'years of development' was honing those specs down to the bone with respect to weight and performance

Insuring people understand the limitations of the design in the real world

that is one hell of an assumption, to think the gear company that's been around for that long is oblivious of such things as performance margins

if you truly cares, why don't you get some proof first? makes for a better education when you have concrete evidence

I think its cool to put one's money where one's mouth is. Healyje spent a hundred bucks give or take, to put his hand-wringing theory to test.

Bravo!

And what's more he posted the results even though they were quite contrary to his stated expectations. So he healyje has integrity as well..........

So in the end? I'd rather shake healyje's hand and smile, than not.

Good on ya, dingus.

Just be careful not to break his hand. His sissy, weak, can't-break-a-cam, hand.

if you'd just pause and think for a moment, you would appreciate how significant FACT #2 is. can your breakage scenario make that happen, breaking a cam with the load of merely pulling down hard at the cam? well, apparently that is possible. i was surprised too, amazed. the equipment angle could no longer hold, unless there's some gross defect, leaving only a natural phenomenon where force can be greatly amplified by just the right flare angle, giving me an absolutely ridiculous force advantage.

the question that needs to be answered, and where the real speculation lies, is whether the statement 'any make cam would have broken (versus blown) in these cases is true or not. I still do not believe that is the case and believe Link Cams are more vunerable to breakage because of the mechanical linkages. Hey, I'd love to be proven wrong, but until I am, I'm standing by my opinion mechanical linkages are inherently weaker than solid material - and hence the need to be more careful and circumspect when using them.

Yeah, could be. Would have to play with them in a crack to get a handle on that one.

GO

no, i haven't. might try that, or someone else can. i don't believe people ever reached that far into that pod to place smaller sized gear, before the Link Cam. or just demonstrate the phenomenon in the lab

It does help. BTW, I couldn't get the file (of Healyje trying to break one with his hands) to upload and tried twice...

. Hope that's understandable.

The fracture resembled that of Dirtme's cam very much. His occurred on a short lead fall. Mine happened as a result of only downward pulls by hand. The force of the pulls were about that of setting a piece hard, but not as hard as all out funking.

Thanks for your email and for your support over the years.
>
> We have tested cams in real rock in all kinds of placements using
> sandstone, quartzite limestone and granite. Repeatability is the key for
> good lab testing during the development of any product. We really put
> these units through the ringer using static tensile tests, our dynamic
> drop tower and a plethora of other highly classified super technical top
> secret developmental testing scenarios. For your information, camming
> devices are tested using file plates when certified. Not exactly
> realistic when it comes to real world use, but again, is reasonable and
> is utilized for consistency purposes at the notified laboratories that
> certify climbing gear. Testing information is not available to the
> general public nor published in any format for public use.
>
> Best Regards,
> Jeff Maudlin
> BDEL

Bryan,

We do all kinds of testing, in all kinds of scenarios. Some official, some unofficial. We don't have detailed or quantitative enough answers to these questions to share. We don't release testing data other than what is required for us to certify these. Everything else is internal, proprietary, and not available to the outside at this time. My apologies and we do appreciate your understanding and support.

Best,
Jeff

That's because you're too old. Got any teenagers around who can do it for you?

Jay

The basic cam's lobes' contact points don't move (relatively) very far:



The LC (three sets of lobes shown independently) has its smaller (extended) lobes traveling much further relatively, and in a direction more perpendicular to the plane of the lobe. I can see how if you have this stuffed into a flaring pocket you could really generate some weird torques.



Sorry that the scales are different in the pictures and the LC doesn't look like a real LC.

That's interesting--and could potentially shed some light into the particular failure mechanism for this cam. Does anyone know if this is how the link cams work? I had always thought that only one set of the retractable cams were in contact with the rock for any given placement--as opposed to all three.

Curt

I think the basics of the diagram are correct, but it's back to front at present. In most cases, it'll be the front (ie. smallest) lobes that will remain relatively stationary (since they're the ones actually camming against the rock), and the large ones (loose, when the small cams are engaged) making the biggest movement.

... Actually, just point the stems in the diagram in the opposite direction. This would be much closer to how the link cams work (smallest at the axle, largest extended along the stem).