Material for ice axe picks
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Hey folks, |
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I would guess that the strength in the picks is almost as dependent on the material as the heat treatment on them. |
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Grivel's picks are listed as chromolly, so 41xx series steel. Probably a forging specific version. I'd probably start with a 4140, as it's widely available, and reasonably strong. I know there's a thread on Backpacking light about building one, and the tests to meet the B/T specs. |
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Did she mean "Armor Steel"? |
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..someting malleable, so it will fit into and take the shape of the holes in the ice...eh? Soft metal is less damage to ice too!/;-) |
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Arik, |
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Here ya go: |
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Pay attention to the last line of the Wired article about hardness/brittleness. There's a correlation between the two, and the last thing you want is a pick that will blow apart or that you can't sharpen. Obviously you need enough strength, to hold a person (or for T type picks take torquing loads) but beyond that extra strength becomes a risk factor, not a benefit. |
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Thanks Folks, that jives with what I was told on ST (but with a whole lot less OT). |
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One thing worth noting is the temperatures at which your pick will be used. Some alloys get a little weird at -20C/-40C. |
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FYI, full hard 4140 is a bitch to machine unless you have tools and machines specifically for working hardened metals. I got a nasty-gram from one of our machinists one time when I spec'd full or half hard. |
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PatCleary wrote:FYI, full hard 4140 is a bitch to machine unless you have tools and machines specifically for working hardened metals.Nah, it's not bad at all (machinability rating of ~55%). Even my little POS benchtop mill handles it just fine provided I keep the cuts light. If you want to really ruin his day, send him some inconel or hastalloy (rated ~20% and below). :) |
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Come to think of it, that guy did complain a lot in general. |
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inconel,hastalloy,waspalloy or any other superalloy must be annealed before machining. I work where the stuff is made and see it done everyday. carbide cutters are required. |
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Yeah, not fun stuff to work with. Lots of advances have been made in hardmilling though, so wouldn't be surprised if people were cutting it hardened nowadays. |
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Malcolm Daly wrote:Here ya go: wired.com/wired/archive/9.0… BITD, BD used a material called Aermet for a high-graded pick material. It was steel used in the landing gear and tail hooks on Navy planes landing of aircraft carriers. It had two fatal flaws: first, more than 50% of them were a bit warped? I guess they were tough to heat treat and then cool down without warping. Second, They were too thin. While they were awesome in really cold brittle ice, they'd rake through in normal ice. Third ( yeah, yeah, I'm counting), they were really tough to sharpen. MalI've got some Aermet picks. The things are well-nigh indestructible. They just won't wear out. They are very tough to sharpen, but they need sharpening a lot less than any other pick. I bought 6 of them when BD discontinued them. Still haven't managed to wear out the original 2, after thousands of meters of climbing. I spoke with a BD guy at the time. He said they broke their machines. |
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My friends and I have spent some time designing tools recently and I'm about ready to cut out the picks with a waterjet. Seeing as it's been a few years, how did your ice tools turn out? What grade did you end up using for the picks and what thickness? |
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4150. The heat treat is more important though. |
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Over the years I've used a lot of different tools, each, seemingly with different pick materials and qualities. Cassin has never impressed me,and I wore through some of their Formula tool picks with regularity. BDs seem Ok , but they get banged up pretty easily,Grivel seem pretty tough. I've only ever seen one pick snap off, and that was from a LaPrade tool many, many moons ago. I seriously doubt you can replicate anything close to what's out there, so, if you can bother, order from Krukongi. I have a pair of their armor plate picks, and for the price, they're hard to beat; you just need to HAVE TOOLS THAT MATCH THEIR SELECTION! The only chance you have of working with chromoly is Cobalt( not Carbide) tools and lots of coolant; once Chromoly heats up you'll form a oxide surface which will need to ground off, otherwise your tool bits will just spin. Mario |