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You can peel a bandaid off, but you can't drag it along the plane of your skin. Replace the bandaid with a rock flake, the skin with a cliff, and the adhesive
by thisrod 16y ago
You can peel a bandaid off, but you can't drag it along the plane of your skin. Replace the bandaid with a rock flake, the skin with a cliff, and the adhesive with ... best not think about it.
In the jargon, "Pull down, not out!"
There's a mechanical advantage issue too. The article discusses camming devices, and those are designed to press the rock harder than they're loaded. Usually, the coefficient of friction between rock and aluminium is less than one. This design also allows the cam to hold in slots that get wider towards the surface.
- jfager 16y agoThanks. To clarify, though, I do understand why one would be safe while the other wouldn't; what I was interested in was the actual technique a climber uses to determine that. In other words: there are certainly rocks for which both vertical and horizontal forces are safe, and rocks for which both vertical and horizontal forces are unsafe, but where and how is the line drawn to determine that vertical is safe while horizontal isn't? Is it just feeling and experience, or are there actual rules people generally follow?
- thisrod 16y agoThere aren't any rules, but the feelings are usually strong ones. Consider the piece of rock in the article. It weighs tons, and has resisted gravity for centuries, so it would take horrible luck for it to fall off while someone was climbing it. On the other hand, no one would plan to fall on it - not even the guy who climbed it.