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Anonymous_Coward wrote:Hey Pete I have an ascender that will slip while loaded. All of the teeth at the top of the cam are worn down. The ascender still grabs with the lower teeth, but while weighted you can rotate it forward and cause the cam to become disengaged. It can then be slid down the rope. As soon as you rotate it back towards yourself, the lower teeth will grab and hold body weight again. Kinda freaky, especially when you don't expect it.
jharman2 wrote:What I found very interesting is that it ONLY slips on 11mm rope. It grabs 10mm and 9mm rope perfectly. The reason is that smaller diameter ropes allow the cam to travel deeper into the shell engaging the lower (good) teeth. So, yes teeth are critical to keeping the device engaged on the rope.
PeterFJohnson wrote:...what Gary Storrick calls eccentric ascenders(load-rope-pivot)...
Bob Thrun wrote:I considered ascender slipping and the need for teeth on the cam in my book, Prusiking.
PeterFJohnson wrote:This might be the information you are looking for. However teeth are only one factor when it comes to whether or not an ascender slips. As a counter example, Alpine Caving Techniques recommends a toothless device - the petzl shunt - under extremely icy or muddy conditions.
Bob Thrun wrote:PeterFJohnson wrote:This might be the information you are looking for. However teeth are only one factor when it comes to whether or not an ascender slips. As a counter example, Alpine Caving Techniques recommends a toothless device - the petzl shunt - under extremely icy or muddy conditions.
But the Shunt is not an eccentric cam device. It is a lever device. A lever device could be made to grip on anything if the lever is long enough
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