Knives are sharpened by grinding against a hard rough surface, typically stone, or a soft surface with hard particles, such as sandpaper. For finer sharpening, a leather razor strop, or strop, is often used.
Sharpening Stone:
A finishing tool that is used to sharpen steel blades of knives and cutting utensils. Most often rectangular in shape, the sharpening stone may be 1/2 to several inches in thickness. There are several different varieties available that are made of a variety of natural and man-made materials. They are available in coarse, medium and fine grit. The coarser the grit the more steel is removed when sharpening. Some stones are available that are double-sided with a coarse grit on one side and a finer grit on the other side. This allows only having to have one stone for sharpening knives. Most stones are used with oil or water to aid in sharpening. The lubricant helps remove the swarf (metal dust), which is created when sharpening the blade edge, from the pores of the stone. Most stones can also be used without the lubricant if desired.
Sharpening Steel:
A tool generally made of steel, which is used to realign the knife's edge in-between sharpenings. Often the knife's edge will bend or roll slightly from normal use. Running it across the steel will straighten the edge and the knife will be sharp again. It is also used after a knife is sharpened on a stone to remove the debris and any irregularities that may be left on the blade edge. The tool can also be glass, ceramic, or diamond-impregnated metal.
V-Shaped Knife Sharpener:
A convenient tool that can be used to sharpen a knife when a person is not comfortable with using a sharpening stone or steel. The tool's casing holds two steel rods coated with diamond abrasive or rods made from tungsten carbide that are positioned to form a V-shape that is at a 20° angle for sharpening. There are many different varieties available, which vary in how they are used. Some varieties contain two stages of sharpening. One stage is coarser and is used for the first stage of sharpening. The second stage has a finer grind for finishing the sharpening process. The knife's edge is pulled across the rods when sharpening. Four to six draws of the blade is usually sufficient to keep the blade well honed. A guard is commonly attached to the sharpener so hands are kept safely away from the knife blades.
Electric Knife Sharpener:
Electric knife sharpening units contain sharpening wheels or stones that offer a quick alternative for sharpening knives. They have a guide that holds the knife at the perfect angle for sharpening. The sharpening wheels or stones are generally made out of Sapphire, ceramic, or are diamond plated. The blade is drawn through the guided slots a couple of times and the blade is sharpened. Some models have 2 or 3 stages of sharpening. The first stage is the coarser grind and then it is finished through a finer grind and honing.
Be aware that using an electric sharpener on a knife that has a bolster will not allow you to sharpen the heel of the blade. You will not be able to run the entire blade through the sharpener without damaging the heel of the knife. If it does not have a bolster it should run through without any problems. When using an electric sharpener, be sure to pay close attention to what you are doing because the sharpener will have a tendency to grind more of the blade away than desired.
