Knife Sharpening - Grinding

Grinding

For sharpening, the sharpener has to be pulled 2 to 4 times over the cutting edge with pressure. After that, the sharpener has to be pulled 4 to 6 times over the cutting edge with light pressure to smooth the edge.

Grinding is generally done with some type of sharpening stone. Sharpening stones come in coarse and fine grits and can be described as hard or soft based on whether the grit comes free of the stone with use. Arkansas, USA is a traditional source for honing stones, which are traditionally used with water or honing oil. India is another traditional source for stones. Ceramic hones are also common, especially for fine grit size. Japanese water stones (both artificial and natural) come in very fine grits. Before use, they are soaked in water, then flushed with water occasionally to expose new stone material to the knife blade. The mixture of water and abraded stone and knife material is known as slurry, which can assist with the polishing of the knife edge and help sharpen the blade. Generally, these are more costly than oilstones. Coated hones, which have an abrasive, sometimes diamonds, on a base of plastic or metal, are also available. Sharpening blocks made with corundum are one of the more expensive types of sharpening stones.

Diamond stones can be useful in the sharpening process. Diamond is the hardest naturally occurring substance known to man and as such can be used to sharpen almost any material. (Coarse diamond sharpening stones can be used for flattening waterstones.) Alternatively, tungsten carbide blades can be used in knife sharpening.

Clamp-style sharpening tools use a clamp with several holes with pre-defined angles. The stone is mounted on a rod and is pulled through these holes, so that the angle remains consistent. Another system is the crock stick setup, where two sticks are put into a plastic or wooden base to form a V shape. When the knife is pulled up the V, the angle is held so long as the blade is held perpendicular to the base.