Replying to How to avoid edge cracks and pull outs.

I've noticed a few posts about edges cracking or pulling out pop up so I thought I'd write a little something about what a common cause of this and how to fix it. As you receive them, the edges in your skis are made of steel that is processed to be ductile (which means the material will permanently stretch, rather than crack, when hit) at real world temperatures. But if you decrease the temperature enough, the steel will go from ductile to brittle and will crack when hit. Now, if you work harden a steel by something like rolling or quenching it, or smacking it against a rail you make it stronger but you also increase the temperature at which the steel will stop behaving in a ductile manner and transition to brittle behaviour. What this means is that the more you hit your edges on rails, the harder/stronger they become but you'll eventually get to a point where the edges behaviour transitions from ductile to brittle. At this point, the edges will develop cracks when hit again. When the skis are then loaded, the tensile forces on the edges will cause the cracks to propagate causing sections of your edge to split. Once this has happened, it's only a matter of time before they'll get pulled out. Avoiding this is easy; tune your skis! The cracks initiate from the hardened, brittle surface material of the edges, if you simply remove it with a diamond stone/file then these critical cracks won't initiate and your edges will last. Also, note to manufacturers: the idea of using thicker and thicker edges to prevent this is not a good one (not from an Engineering perspective, at least) and won't prevent this type of edge cracking. In fact, I wouldn't be surprised if the idea for thicker and thicker edges came out of the marketing or business development departments of a company that manufactures ski edges. Same goes for using steel processed to be stronger. Thicker, stronger edges may help with massive one off hits against a heavy sharp rock, but that doesn't appear to be nearly as common a problem for park skis as what's causing the problems NS'ers have been describing. Thicker edges will only work if it means that people tune them more often because they are not afraid of running out of material. Otherwise, thicker edges are useful for nothing apart product differentiation/ marketing purposes.