Lie-Nielsen A2 Tool Steel Blades are cryogenically treated, hardened to Rockwell 60-62 and double tempered. They use a heat treating technique that ensures the blade will take and hold a very fine edge for a long time. Lie-Nielsen have designed these blades to fit their tools, not other makers'.
After heat treating, the blade is fully surface ground on the top, back, and cutting edge, giving a smooth, flat surface that will take a mirror finish very quickly.
Lie-Nielsen blades are thick to provide solid, chatter-free cutting. They come ready to use, but honing a secondary bevel of 5° to 10° will increase performance, help achieve a razor edge quickly, and improve edge life in hardwoods.