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Earlier in this thread R Jordan described his testing of the Helix axe for self-arrest.
Based on those results, I think I'd be comfortable using the Helix for cutting steps, and also for SELF-ARREST with the following provisos: -axe undamaged (mainly an issue for the shaft). -chances of needing to self-arrest very low. -no rope carried on the trip (no crevasse rescue, no use of the axe as a rope anchor). -slope angle low to moderate. -no hard ice (aluminum head unsuitable) -not many rocks in the snow (could shatter the shaft). -combined weight of person plus backpack not too large.
Self-arrest is (hopefully) a rare event. A much more frequent use is self-belay, where the spike is plunged as far as possible into the snow and one grabs the shaft or head of the axe. Self-belay is frequently employed to gain stability when traversing or ascending a steep slope, and it is also used to arrest a slip, hopefully obviating the need for self-arrest.
I'm not sure whether the Helix would be suitable for self-belay: - Is the shaft strong enough? Self-belay stresses the carbon-fiber shaft, in contrast to self-arrest where all the stress passes through the aluminum head. - Is the shaft wide enough? The buried shaft of the Helix will provide less resistance than a regular axe because the Helix's shaft has a narrower cross-section. The amount of resistance is crucial to self-belay.
At present there is almost no data available on the strength of the carbon fiber shaft under the forces that arise during self-belay. That's in stark contrast to trekking poles, where Luxury Lite, Titanium Goat, Bozeman Mountain Works and Gossamer Gear all provide detailed information about the strengths and weaknesses of their poles, including data from destructive testing. That data indicates that the Luxury Lite and Ti Goat poles are the strongest, while the Gossamer Gear poles are the lightest. Is the strength of the Helix shaft comparable to a Gossamer Gear shaft, a Luxury Lite shaft, or stronger than all of the above? Surely it is more important to provide data for an ice axe than for trekking poles!
Edited by benwald on 05/28/2006 17:33:02 MDT.
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