When grinding your knife on a stone, it may be helpful to use a three-way oil stone, Fine-Medium-Coarse. Use the stone only when your edge does not realign with a steel. That means your edge has dulled from constant use or steeling. Make sure you use the exact angle at 30 to 40 strokes before your new edge is formed. Use more strokes if needed. The angle used is determined by how sharp you want the knife, the smaller the angle the sharper the edge. But remember that the sharper the edge the sooner it will fade, and will need to be re-sharpened.