A sharp knife-edge is so thin that, as it cuts, it tends to curve and curl to one side or simply wear out. When an edge is curled, it feels dull. A Steel is good for straightening an edge. For best results, a knife should be steeled with each use. Unless the steel is used frequently, it is of marginal value only.
Steels range in size from eight to fourteen inches.
Longer steels are easier to use and increase safety. A coarse steel works quicker, but can leave a rougher edge. Some steels are magnetic , which helps keep the knife-edge in constant contact with the steel, retain metallic particles. When using a steel, it is usually safer for neophytes to draw one hand away from the other. Even with a cross guard on the steel, a moment of carelessness can result in a painful accident.