Whetstone (tool)

Sharpening stones, water stones or whetstones are used to sharpen the edges of steel tools and implements through grinding and honing.

Examples of items that can be sharpened with a sharpening stone include scissors, scythes, knives, razors, and tools such as chisels, hand scrapers, and plane blades.

Sharpening stones come in a wide range of shapes, sizes, and material compositions. Stones may be flat, for working flat edges, or shaped for more complex edges, such as those associated with some wood carving or woodturning tools. They may be composed of natural quarried material, or from man-made material.

Stones are usually available in various grades, which refers to the grit size of the particles in the stone. Generally, the finer the grit, the denser the material, which leads to a finer finish of the surface of the tool. Finer grits cut more slowly because they remove less material. Grits are often given as a number, which indicates the density of the particles with a higher number denoting higher density and therefore smaller particles.

Though "whetstone" is often mistaken as a reference to the water often used to lubricate such stones, the term is based on the word "whet", which means to sharpen a blade, not the word "wet". The verb nowadays usually used to describe the process of using a sharpening stone is to sharpen, but the older term to whet is still sometimes used. The term to stone is so rare in this sense that it is no longer mentioned in some major dictionaries, for example the Oxford Living Dictionaries.

The Roman historian Pliny described use of several naturally occurring stones for sharpening in his Natural History. He describes the use of both oil and water stones and gives the locations of several ancient sources for these stones.

The use of natural stone for sharpening has diminished with the widespread availability of high-quality, consistent particle size artificial stones.

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