Work Sharp Ken Onion Edition Knife and Tool Sharpener (Mk.1 & Mk.2) manufactured for precision sharpening of high-strength steels. The grit symmetry, spacing, and backing flexibility are all designed to produce the optimal convex edge with minimal heating or material takeoff. If you’ve ever used a belt sander to sharpen, you know how quickly the steel heats and how much excess material can be removed if you aren’t careful. Our abrasives are a key component of our success in the sharpening world.