BD Laser Hard Ice Modification

Eric and Lucie wrote: Assuming you exert a fixed amount of force on your shaft (thereby inducing a fixed amount of bending moment in the pick, M) when you remove your tool, regardless of the design of the pick (Note: this is a BIG assumption, since a better pick design should require less removal force... but thickness and detailed tooth design probably affect removal effort more than height), then the peak bending stress in your pick is: s = M * (h/2) / (t*h^3 / 12) = (6*M)/(t*h^2), where M is the maximum bending moment applied to your pick when removing your tool, t is the thickness of the pick at the location where the moment is maximum, and h is the height of the pick at that location. (look up beam bending stress on Wikipedia if you want a reference)

Using s=(6*M)/(t*h^2) with some approximate numbers such as
M=1000N/mm, t=3.5mm, h=11mm would give 14.17MPa.
Assuming the same moment and reducing h by 20% or 0.8*h would give 22.14MPa.
(22.14-14.17)/14.17=56% increase in stress with 20% reduction in height.

Changes in section height change bending stress exponentially or 1/((% of original height)^2).

I noticed that the pick teeth on my BD's are much sharper then my buddy's Grivel pick teeth and they could be pulled out of the ice much easier. I liked that I didn't have to fight the ice to remove the picks on the Grivels but I also like that my BD picks feel much more secure when placed deep allowing me to weight them when my feet are sketchy....

rocknice2 wrote: I've been messing around with modifying a few BD Laser picks. The height goes from 11mm to 9.5mm and thickness is thinned to 2.8mm.

Nice to see that BD has taken my advice and thinned their new Natural Ice/Ice+ Picks. Petzl too, with the Pur'Ice.

rocknice2 wrote:

Nice to see that BD has taken my advice and thinned their new Natural Ice/Ice+ Picks. Petzl too, with the Pur'Ice.

You were right then, and you're still right now, but it took a few years for the mfrs to make the compromise. The Pur'Ice seems to work well (as did thinned Ice/Laser picks, BITD).