[pct-l] Ice Axe +/- Clearanc

[pct-l@mailman.backcountry.net (Jim Mayer)]

Hmmm.... On page 282, the 6th edition says:

    The pick may have positive, neutral, or negative clearance.... <snip>
    In theory, the degree of clearance affects the performance of the axe
    in self arrest.  A pick with positive clearance should penetrate more
    readily; a pick with negative clearance would tend to skate on ice or
    hard snow.  However, the type of clearance actually makes little
    difference; self-arrest is almost impossible on ice, and in softer snow
    the pick will dig in regardless of clearance.  In any case, you can
    always modify clearance with a hand file.

Maybe I should have read that section before posting!

Anyway, the climbing magazine argument still makes sense to me.  They
basically claim that an axe with positive clearance can grab suddenly on
harder snow, while axes with negative clearance are easier to control.  Of
course, one can make good sounding arguments about almost anything, so who
knows!

-- Jim

----- Original Message -----
From: "Richard Winterstein" <agrestis9@hotmail.com>
To: <pct-l@mailman.backcountry.net>
Sent: Friday, January 05, 2001 2:19 AM
Subject: [pct-l] Ice Axe +/- Clearanc


> Hi ->  These are described as having positive clearance and negative =
> >clearance.  In a positive tip design, the tip of the pick angles away =
> >from the shaft of the axe... kind of like this:>
> >     ____________
> >    /_____   _____|
> >          | |
> >
> >In a negative tip design, the pick angles towards the shaft, like this:>
> >     ____________
> >     \____   _____|
> >          | |
> >
> >Now, the ice axe info at REI says that a postive clearance design is =
> >better for self arrest and that a negative clearance design is better =
> >for overhead hooking in ice climbing.  On the other hand, Climbing =
> >magazine's online site argues that a =
> >negative tip design is superior because the postive tip can catch in =
> >hard snow and yank the axe away... they state that a postive tip is used
=
> >for vertical ice tools.
>
> The 4th edn. of _Mountaineering:_The_Freedom_of_the_Hills_ agrees with REI
> on the matter of self-arrest.  Picks with positive clearance, it says, do
a
> good job of biting into the surface.  Picks with negative clearance tend
to
> skate or drag along the surface.  That's a rather old edition I've quoted
> from, however; does anyone have a current edition they can consult to see
if
> perhaps this information has been revised?
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com
>
> _______________________________________________
> PCT-L mailing list
> PCT-L@mailman.backcountry.net
> http://mailman.backcountry.net/mailman/listinfo/pct-l
>