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Sharpening Glossary

A

Alloy - an homogeneous mixture of metallic elements possibly also including one or more non-metallic elements. Alloys have different properties than non-alloyed metals and the proportions of their constituent elements can be varied to achieve desired properties of hardness, corrosion resistance, etc. Steel, brass and bronze are examples of alloys.

Aluminum Oxide - a crystal consisting of two Aluminum and three Oxygen atoms used as an abrasive in sharpening stones, compounds and powders. Also called Alumina or Corundum.

Arkansas Stone – a natural stone quarried from Ozark novaculite (silicon quartz). Due to their unique crystalline structure, Arkansas stones polish as they sharpen, imparting a keen smooth edge/surface. Available in different grits, these stones are listed in order of coarsest to finest: Washita, Soft Arkansas, Hard Arkansas, and Hard Translucent Arkansas.

B

Belgian Blue Whetstone - a natural stone used for sharpening. Characterized by a high concentration of spessartite garnets, they have a blueish-purple color caused by the presence of iron in the stone. Used with water, these stone form a slurry in use. They are similar to Coticule Whetstones which they are often found near, and sometimes these two stone types occur in adjacent layers naturally joined to one another. Named for the country of Belgium where they are quarried. Their name is often abbreviated as BBW. See also: Coticule Whetstone, Spessartite, Whetstone.

Bench Stone – an abrasive product in block form used for sharpening knives, tools, etc. Typically used to describe a stone of a size that is convenient to use by placing it on a bench or other work surface as opposed to a stone that would be held in the hand. See also: Sharpening Stone, Stone, Whetstone.

Bevel – the angle or inclination of a line or surface that meets another at any angle but 90 degrees. One of the surfaces that intersect to form an edge.

Burnisher – a tool, usually with a hard, smooth surface, often round or oval, that is used to turn over a burr on scrapers.

Burr - a ragged protrusion of metal formed on an edge by abrasion or by burnishing. A burr forms on the side of the edge opposite from the side that is against the sharpening or burnishing surface. A burr can be used as an indicator of sharpening progress as its presence indicates a crisp intersection of two bevels. On knives and cutting tools the burr is usually removed as the final step of sharpening. On scrapers, the burr itself performs the cutting action of the tool and is deliberately left in place. See also: Burnisher

C

Camber - an arch or convexity to the shape of an edge.

Carbide - the shortened name for Tungsten Carbide. A compound of tungsten and carbon used to make cutting tools because of its extreme hardness and resistance to high temperatures. Sharpening tungsten carbide cutting tools requires very hard abrasives such as diamond or cubic boron nitride.

Carbon Steel - any steel in which carbon is the main alloying element. In general, higher carbon content makes steel harder. Or any steel that is not stainless steel.

Carborundum Stone - a stone manufactured with silicon carbide abrasives. See also: Crystolon Stone, Silicon Carbide Stone

Ceramic Knife - a knife with a blade made from a ceramic material, often zirconium dioxide, instead of the more usual steel. Ceramic blades are very hard and hold an edge very well, often better than steel. However, they are difficult to sharpen, usually requiring the use of diamond abrasives.

Ceramic Stone - also called Ceramic Honing Stone or Ceramic Sharpening Stone. A stone manufactured as a fused block or rod of ceramic material. Ceramic Stones are very hard wearing and usually used dry, without oil or water as a cutting fluid. Available in medium, fine and ultra fine stones that correspond to roughly 600, 1200 and 2000 grits respectively. Ceramic Stones are not the same as and should not be confused with Ceramic Water Stones.

Ceramic Water Stone - a specific type of Water Stone, a Ceramic Water Stone is a composite ceramic product in which individual pieces of ceramic abrasive material are held together with a resin binder. They are used with water as a cutting fluid like other water stones, however they are harder wearing than other water stones and do not require soaking prior to use. Available from 122.5 micron/120 grit through .49 micron/30,000 grit. Ceramic Water Stones are not the same as and should not be confused with Ceramic Stones.

Chromium Oxide - an inorganic compound consisting of 2 chromium and 3 oxygen atoms which forms hard crystals and is often used as an abrasive. Chromium oxide is green in color and is often used as a pigment. Honing compounds made with it are often referred to by names such as green honing paste or green rouge. It is one of the grits in our Green Honing Compound.

Continuous Surface - referring to a a diamond sharpening stone on which the diamonds evenly cover the entire surface without voids or interruptions. Useful for small or finely pointed tools that can catch in the voids of an interrupted surface.

Coticule Whetstone - a natural stone used for sharpening. Characterized by a high concentration of spessartite garnets, they have a characteristic white-yellow color. Somewhat brittle, they are often affixed to a separate piece of slate as a backing stone to prevent breakage. The slate is intended for structure only and is not used in the sharpening process. Used with water for sharpening, they form a slurry in use. Quarried in the country of Belgium, they often occur near Belgian Blue Whetstones and sometimes these two stone types occur in adjacent layers naturally joined to one another. See also: Belgian Blue Whetstone, Spessartite, Whetstone.

Crystolon Stone - a stone manufactured with silicon carbide abrasives. These are the fastest cutting oil stones we carry. If speed is more important than the ultimate quality of the edge, the Crystolon bench stones are a good choice. Gray in color. Available in coarse, medium, and fine grits.

Cubic Boron Nitride - a specific crystalline form of boron nitride used as an abrasive consisting of equal numbers of boron and nitrogen atoms and having a hardness second only to diamond. Sometimes abbreviated as CBN.

Cutting Fluid - a fluid used in sharpening to float away swarf in order to avoid clogging the sharpening stone. Usually water or oil.

D

Diamond - a crystalline form of pure carbon used as an abrasive. The hardest of known minerals.

Diamond Stone - a stone containing small diamonds attached to the face of a metal plate and used for sharpening knives, tools, etc. The two greatest advantages of the diamond stone are the very fast cutting that the diamonds provide and the flatness that is retained by the diamond stone. Diamond stones are made in continuous surface or interrupted surface formats and are available in grits from 120 micron/120 mesh to 3 micron/8000 mesh.

E

Edge - the line of intersection of two surfaces. A highly sharpened edge is one where the two surfaces are highly polished to form a very fine intersection.

F

Flattening Stone - an abrasive plate or stone used to flatten or resurface a sharpening stone. See also: Lapping Plate, Lapping Stone.

Fleam - the leading edge of a saw tooth.

G

Grind - to remove material or sharpen by abrasion, particularly as done with an abrasive wheel.

Grinding Wheel - a sharpening stone in the form of a wheel or disk that spins on an arbor.

Grit - a generic term for the abrasive particles used in sharpening. Or the numeric term used to describe the number of openings per linear inch in a screen used to sort particles; a measurement of abrasive grains. Low grit numbers are coarser and high grit numbers are finer. See also: Mesh.

H

High-Speed Steel - any of several types of tool steel formulated to retain their hardness at high temperatures. Cutting tools made of high-speed steel are used in environments of high heat or friction such as lathe turning. Sometimes abbreviated as HSS.

Hollow Grind - a bevel that has been shaped on a grinding wheel such that it is concave rather than flat. Or to create such a bevel.

Hone - a fine-grained whetstone for giving a keen edge to a cutting tool. Or to sharpen on a fine-grained whetstone.

Honing Compound - fine abrasive either in powder form or mixed in a medium such as wax to make a bar or paste. Used for polishing an edge. Honing Compounds are usually used with a strop. See also: Honing Paste, Honing Powder.

Honing Paste - fine abrasive mixed in a medium such as wax to make a paste. Used for polishing an edge. Honing Pastes are often used with a strop. See also: Honing Compound, Honing Powder.

Honing Powder - fine abrasive in powder form. Used for polishing an edge. Honing Powder is often used with a strop. See also: Honing Compound, Honing Paste.

Honing Guide - a jig used to hold a tool or knife steady during sharpening, increasing efficiency by ensuring a consistent bevel angle. See also: Sharpening Guide, Tool Sharpening Guide.

Honing Oil - a non-hardening liquid, usually mineral oil, used as a cutting fluid when sharpening with oil stones.

I

India Stone – a stone manufactured with aluminum oxide abrasive. Preferred for imparting durable, smooth-cutting edges and for close tolerances. Orange/brown in color. Available in coarse, medium and fine grits.

Interrupted Surface - referring to a diamond sharpening stone on which the diamond covered surface features periodic voids which trap metal debris during sharpening. This trapping of debris prevents clogging of the diamond grit and speeds sharpening.

Iron - A ductile, malleable metallic element used as a base in alloys to create steel used for making cutting tools. Or the cutting blade of a woodworking hand plane. See also: Plane Iron.

K

Keen - finely sharpened.

L

Lapping Plate - an abrasive plate or stone used to flatten or resurface a sharpening stone. See also: Flattening Stone, Lapping Stone.

Lapping Stone - an abrasive plate or stone used to flatten or resurface a sharpening stone. See also: Flattening Stone, Lapping Plate.

M

Mesh - the numeric term used to describe the number of openings per linear inch in a screen used to sort particles; a measurement of abrasive grains. Low mesh numbers are coarser and high mesh numbers are finer. See Also: Grit.

Micron - one millionth of a meter or one thousandth of a millimeter. Sometimes used to measure abrasive particles. The higher the micron number, the coarser the abrasive and the lower the micron number the finer the abrasive.

N

Nagura - the Japanese word for any stone which is applied to any other sharpening stone for the purpose of creating an abrasive slurry or for cleaning the surface of that sharpening stone

Novaculite - a fine grained sedimentary rock containing microcrystalline quartz. Arkansas Stones are made of Novaculite.

O

Oil Stone - a stone made of one of three following materials: novaculite, aluminum oxide, or silicon carbide which uses oil as a means to remove the swarf. Arkansas Stones, Crystolon Stones and India Stones are all Oil Stones. The good overall performance and the modest price are the oil stone’s greatest assets.

P

Plane Iron - the cutting blade of a woodworking hand plane. See also: Iron.

Polish - to make smooth and glossy by friction. Or to sharpen using very fine grit abrasive after coarser abrasives have been used to create an edge.

R

Razor Strop - a type of strop consisting of a belt or strap of leather or fabric used by anchoring one end to a fixed point and grasping the other by hand to pull the belt taut. Razor Strops may be used with or without honing compound applied to their surface. The name Razor Strop reflects this type of strop's close association with preparing straight razors for shaving. See Also: Strop.

Rockwell Scale - a scale used to measure the relative hardness of materials based on the penetration depth of an specific type of indenter under a standard load. Various Rockwell scales are used for different materials, and each scale has a different letter designation. The C scale is used for steels and is indicated as Rockwell C or HRC followed by a number. The higher the number, the harder the steel. Rockwell values for knives and woodworking tools are typically in the 50's - mid 60's.

S

Serrated - having a notched edge or sawlike teeth.

Sharpening - the process of removing material to create a cutting edge.

Sharpening Angle - the degree of inclination at which a tool is held relative to the sharpening stone.

Sharpening Guide - a jig used to hold a tool or knife steady during sharpening, increasing efficiency by ensuring a consistent bevel angle. See also: Honing Guide, Tool Sharpening Guide.

Sharpening Stone - an abrasive product in block form used for sharpening knives, tools, etc. See Also: Bench Stone, Stone, Water Stone, Whetstone.

Silicon Carbide - an extremely hard blue/black crystalline substance consisting of one Silicon atom and one Carbon atom. Used as an abrasive in sharpening stones, powders and compounds.

Silicon Carbide Stone - a stone manufactured with Silicon Carbide Abrasive. See Also: Carborundum Stone, Crystolon Stone.

Spessartite - A form of garnet composed of manganese aluminum silicate and named for a region of Bavaria where it is found. It is the abrasive mineral in Belgian Blue Whetstones and Coticule Whetstones. See also: Belgian Blue Whetstone, Coticule Whetstone.

Stainless Steel - any of several steel alloys that are resistant to corrosion due to the relatively large amounts of chromium they contain. Used to make cutting blades when rust resistance is important, such as with kitchen knives.

Steel - a metal rod designed for sharpening or realigning the edge of knives. Or the iron alloy most commonly used to make edged cutting tools.

Stone - A small piece of rock like a pebble. Or an abrasive product in block form used for sharpening knives, tools, etc. See also: Bench Stone, Sharpening Stone, Water Stone, Whetstone.

Strop – any of several devices used for sharpening, especially for polishing to a high degree of sharpness. Strops often consist of a piece of leather or cloth, which may be attached to a solid base like a piece of wood or left unmounted as a hanging belt or strap, but can also be made of uncovered wood or sometimes of synthetic material. Strops are sometimes shaped to specific shapes or contours to fit particular tools such as carving gouges. Strops are often used with honing compounds applied to their surface but can be used plain. Or to use such a device to sharpen. See Also: Razor Strop.

Surgical Steel - Any of several grades of stainless steel commonly used for the manufacture of medical implements. There is not a universally accepted definition of what constitutes a surgical steel, and manufacturers apply the term at will. See also: Stainless Steel, Steel.

Swarf – fine metal filings or shavings removed by a cutting tool, sharpening stone, or abrasive.

T

Temper - to give a desired hardness to steel through a process of controlled heating and cooling. Or the particular hardness imparted to steel through this process. Excessive heat created during the sharpening process can reduce this hardness.

Tool Sharpening Guide - a jig used to hold a tool or knife steady during sharpening, increasing efficiency by ensuring a consistent bevel angle. See also: Honing Guide, Sharpening Guide.

Tool Steel - any of several varieties of steel that are used for making tools because their properties of hardness, abrasion resistance and edge retention make them particularly suited to that purpose.

Tungsten Carbide - a compound of tungsten and carbon used to make cutting tools because of its extreme hardness and resistance to high temperatures. Sharpening tungsten carbide cutting tools requires very hard abrasives such as diamond or cubic boron nitride. Sometimes referred to in the shortened form of Carbide.

W

Water Stone – an abrasive stone, available in both natural and synthetic material, used to sharpen knives and tools with water as a means to remove the swarf. Fast cutting stones, water stones tend to wear unevenly which necessitates periodic flattening. Available in grits from 122.5 micron/120 mesh to .49 micron/30,000 mesh.

Whet - to sharpen by abrading or grinding. Now a somewhat archaic word.

Whetstone – an abrasive product in block form used for sharpening knives, tools, etc. Often confused with Water Stone because of the phonetic similarity between "wet" - soaked with water, and "whet" - to sharpen. All sharpening stones are whetstones. Only some whetstones are water stones. See also: Bench Stone, Sharpening Stone, Stone

Z

Zirconium Dioxide - a crystalline material consisting of one zirconium and two oxygen atoms also known as zirconia or zirconium oxide. A very hard ceramic material, zirconium dioxide is used for making ceramic knife blades. Zirconia is also used as an abrasive material in heavy-duty sanding belts.