This was my first attempt at a fillet knife. It's made from 440C and has linen micarta handles with stainless pins. The challenge with the fillet knife is the heat treat. I started with 1/8 inch stock, profiled the blade, surface ground the steel and then it went to heat treat. If I started the grind before heat treat I risked it warping during heat treat. Once it went through heat treat the grinding was done at slower speeds with bare hands to make sure the heat treat was not ruined. It was a slower process than a normal knife. I made a jig to maintain a consistent angle that included a backing so the blade didn't flex. In the end it turned out great. It has good flex through about the half way point on the blade and always comes back to center. It maintains a razor sharp edge and the black linen micarta handles give a great mix of modern and woodsy appearance.