![]() The finest level of sharpening is done most frequently, while the coarser levels are done progressively more rarely, and sharpening methods differ between blades and applications.įor example, a straight razor used for shaving is stropped before each use, and may be stropped part-way through use, while it will be fine sharpened on a stone a few times per year, and re-ground on a rough stone after several years.īy contrast, a kitchen knife is steeled before or after each use (and may be steeled during heavy use, as by butchers), and sharpened on a stone a few times per year.īlades are damaged primarily by buckling – compressive force, from being pressed into a hard object, such as bone, ice, or a hard cutting board – and by bending, from sideways pressure. The word "honing" is ambiguous, and may refer to either fine sharpening (step 1.2) or straightening (step 2). stropping, on a razor strop or buffing on a wheel.grinding (on a grinding wheel) or whetting (on a whetstone).Named by tools, the same three stages are: polishing may also be achieved by buffing a blade: instead of moving the knife against a flat leather strop loaded with fine abrasive, the knife is held still and a powered circular cloth wheel is moved against the knife.polishing (also called stropping): giving a mirror finish, but not significantly altering the edge.straightening: straightening the existing metal on the blade, but not removing significant quantities of metal.fine sharpening (using the same tools as above, but in finer grits).rough sharpening (using either water stones, oil stones, or medium grits of sandpaper).sharpening: removing metal to form a new edge.These may be referred to either by the effect or by the tool. Knife sharpening proceeds in several stages, in order from coarsest (most destructive) to finest (most delicate). Method Two professional knife sharpeners in streets of Kathmandu Knife sharpening with 14th century methods. The Western-style kitchen knives are generally in the range of 52–58 on the Rockwell scale, which denotes the relative hardness of a material. For example, Western kitchen knives are usually made of softer steel and take an edge angle of 20–22°, while East Asian kitchen knives are traditionally of harder steel and take an edge angle of 15–18°. The composition of the stone affects the sharpness of the blade (a finer grain, usually, though not always, produces sharper blades), as does the composition of the blade (some metals take and keep an edge better than others). In general, but not always, the harder the material to be cut, the higher (duller) the angle of the edge. At the other extreme, an axe for chopping wood will be less sharp still, and is primarily used to split wood by chopping, not by slicing, and may be reground but will not be sharpened daily. Kitchen knives are less sharp, and generally cut by slicing rather than just pressing, and are steeled daily. Typically these are stropped daily or more often. Straight razors used for shaving must cut with minimal pressure, and thus must be very sharp with a small angle and often a hollow grind. For example, surgical scalpels are extremely sharp but fragile, and are generally disposed of, rather than sharpened, after use. Knives that require a tough edge (such as those that chop) may sharpen at 25° or more.ĭifferent knives are sharpened differently according to grind (edge geometry) and application. The edge angle for very sharp knives can be as little as 10 degrees (for a 20° included angle). Typical edge angles are about 20° (making the included angle 40° on a double-ground edge). The total angle from one side to the other is called the included angle – on a symmetric double-ground edge (a wedge shape), the angle from one edge to the other is thus twice the edge angle. The angle between the blade and the stone is the edge angle – the angle from the vertical to one of the knife edges, and equals the angle at which the blade is held. The smaller the angle between the blade and the stone, the sharper the knife will be, but the less side force is needed to bend the edge over or chip it off. Additionally, a leather razor strop, or strop, is often used to straighten and polish an edge. Knife sharpening is the process of making a knife or similar tool sharp by grinding against a hard, rough surface, typically a stone, or a flexible surface with hard particles, such as sandpaper. The Knife Grinder by Massimiliano Soldani (c.1700), Albertinum, Dresden A railway camp cook sharpens a knife blade on a stone wheel, 1927 JSTOR ( March 2010) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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