It's been so long since I've been able to buy quality drill bits at my local store that I've forgotten how a drill bit actually cuts through metal. Offshore material is useless for anything but plastic or softwood. These bits work exactly as I recall until imported drill bits showed up. (You know, actually plunging into the material being drilled, not just sharpening it to oblivion). I suspect these drill bits can actually be sharpened like any quality drill bit when the time comes. Based on my past usage I don't expect to need to sharpen these bits any time soon. Now I can actually use each drill more than once before throwing it in the trash.