Anneal: The process of using heat to relieve stresses within a metal. At a heat usually near 2/3rds of the metals melting point re-crystallization occurs, creating a more flexible alignment among the crystals.

Anodizing: This refers to the use of a current of electricity to affect the surface of a metal. It's most common usage is in aluminum anodizing or in the coloring of reactive metals such as niobium or titanium. The term comes from the negative pole of an electrical circuitry, the anode.

Austenite: A solid solution of steel in which small carbon atoms are trapped within larger iron atoms. This structure is generally unstable at room temperature. It is a phase through which steel passes on the way to becoming hard martensite or soft pearlite or ferrite.

Bluing: The process of applying heat and / or chemicals to metal in order to achieve a color oxidation.

Bolsters: The forward part of the handle, usually metal material in front of and/or in back of the scales.

Brass: An alloy of copper and zinc.

Buff: To polish to a highly reflective shine.

"C" Scale: This refers to the dial of a Rockwell testing machine on which is indicated the degree of penetration of a diamond point under a specific load.

Carbon: The mineral that transforms iron into steel. High-carbon steel results when .5 percent or more carbon is present. Only a bare .8+ can be absorbed by the iron, the balance in extremely high carbon steel goes to add hardness.

Cast Iron: An alloy containing between 2% and 4.5% carbon. It is hard and brittle.

Chamfer: To remove an edge or corner, to bevel.

Choil: The cut away area in front of the guard of some knives, it may be large enough to fit a finger or a very tiny cut out area, a choil is a negative, it is an area that is not there.

Corrosion Resistance: The ability of steel to resist the formation of oxides. Steels with high corrosion resistance are commonly called "stainless".

Critical Temperature: The point at which carbide particles in steel begin to dissolve into their surrounding matrix, creating the phase called austenite. The temperature range in which this austenizing takes place is called the critical range.

Damascus: The name given to pattern-welded steel, a laminated structure known for amazing patterns.

Decalescence Point: In heat-treating steel, the temperature at which pearlite changes into austenite.

Die: Commonly signifies a device for forming a male thread on a shaft or rod. Otherwise, any tool used to form metal by compression.

End Mill: A cylindrical milling cutter with cutting faces on its end and usually on its sides as well.

Engraving: The application of decoration to metal by cutting the pattern directly into the surface with special tools such as the burin and graver.

Epoxy Resin: An adhesive consisting of two viscous constituents which, when mixed together, react to form a solid mass.

Escutcheon: A shield or plate set into the handle to be engraved with the owners name or initials.

Etching: The application of acid that "bites" into the exposed surface of a blade. In the case of Damascus, the
acid “eats” the different types of steel at a different rate leaving behind the pattern.

Ferric Chloride: A corrosive salt substance used to etch copper and brass and often used to bring out the pattern in Damascus steel. Used as a liquid and cut with distilled water and/or vinegar.

Ferrite: A relatively soft solid solution in which carbon atoms are trapped between body-centered cubic iron crystals.

Ferrous: Literally "of iron", a metal, the main constituent of which is iron.

File Work: Decorative patterns created by selective removal of small areas of steel with a needle file. In knife making this usually refers to small-scale ornamentation on edges.

Fire Brick: Refractory bricks made specifically for use in high temperature applications such as to line the inside of kilns and ovens or to solder upon.

Fire scale: An oxide of copper that forms within sterling and gold alloys when heated, particularly in the presence of free oxygen. It appears as a purple to black stain.

Flat Ground: The surface of the blade is flat from, or near the spine of the blade tapering to the cutting edge bevel.

Flutes: Straight or spiral grooves between the cutting faces of a tap, reamer or drill bit. The flutes provide for the clearance of removed material.

Flux: A chemical substance used to absorb oxides and prevent them from forming on metal.

Forge: To form or shape metal while it is red-hot with blows by a press or hammer. This term also refers to the hearth on which a fire is maintained for the purpose of heating metal.

Full-Tang: A style of knife construction in which the steel of the blade extends through the full shape of the handle. This is generally recognized as the strongest of all blade configurations.

Grains: In reference to metal or steel, a cluster of crystals with a common orientation. Grain size is important to knife makers because grain size affects the strength of a metal. A large-grain structure, because it has fewer grain boundaries, is not as strong as small-grained material. Hardening creates small grains. Annealing creates larger
grains which make it easier to machine.

Guard: A cross-piece that separates the handle from the blade of a knife or sword and protects the users hand. In swords this is also called the hilt.

Harden: To cause a change in the crystal structure of steel that increases its wear resistance and toughness. This is commonly done through quenching the steel when it has reached a specific temperature.

Hardness: The ability of a material to resist penetration.

Hollow Ground Blade: A blade in which the cross-section incorporates concave facets, requiring very skilled forging and grinding. It potentially offers a very sharp edge. It is done by grinding the blade on a round surface (face of a wheel) with a sanding belt on it and forming a concave hollow above the cutting edge and below the top edge of the blade.

Inlays: Regarding knives, it is usually a material that is set flush with a surface and locked in place with undercuts and adhesives. In leather work, it is usually a dissimilar leather or exotic skin that is sewn in place between two
pieces of tooling leather for decorative purposes.

Kiln: A high temperature oven with many available uses.

Lay-out: To arrange or draw the pieces. There is an important distinction between this and designing. Designing is a conceptual activity. Once it has been done, the pieces of the design can be laid out.

Lay-out Dye: An alcohol-based paint used to facilitate marking on metal. This paint, often blue, is brushed onto steel where it dries quickly. A sharp point, like a scribe, will leave a bright highly visible line when scratched through.

Martensite: A phase of hardened metal. In the case of steel it is formed by quenching the material when it is heated to the critical range. The result is a tough, brittle material that when viewed under a microscope, resembles a pile of straw.

Milling: A method of removing metal in which the work piece is brought into contact with a tool mounted on a rotating spindle.

Moh's Scale: A system of relative hardness between substances. This scale was devised for mineral identification and uses ten minerals to demarcate points on a continuum that runs from talc (#1) to diamond (#10). Annealed steel is about 5 on the scale. Hardened steel is about 6 1/2.

Mokume-Gane: A technique in which multiple layers of soft metals like brass, copper or nickel silver are fused together right below their melting points and then distorted to reveal a patterned material. In most cases the resulting material can be treated like any other soft metal.

Needle Files: Small files between 3 & 6 inches long. They are available in many shapes and several degrees of coarseness. Needle files are measured by their whole length, while other files are measured by the tooth section.

Normalizing: The process used to relieve stresses in steel. The material is heated to about 100 degrees above its critical temperature and allowed to cool in air. This creates an even grain pattern and a malleable steel.

Oosic: The penile bone of a walrus – as it relates to knife making, it is usually several hundred years old.

Oxidizing: The process in which oxygen combines with elements to create new compounds called oxides. These are detrimental to metal and should be avoided.

Partial-tang: A style of knife construction in which the tang extends partway into the handle. The tang can be a narrow shaft that is enclosed in the handle or as wide as the handle.

Patina: Any of hundreds of surface films on metals to provide a desired color or surface finish.

Pattern-welded steel (Damascus): A method of blade manufacture involving the forging and hammer welding of both iron and steel together to form a specifically patterned homogenous metal. The pattern is revealed through polishing and acid etching.

Pearlite: The relatively soft phase of annealed steel made up of ferrite and cementite.

Pommel: Traditionally a spherical knob, often decorative serving as a counter-weight at the opposite end of a sword to the point.

Quench: To plunge heated steal into a medium such as oil to cool it. The more rapidly the quenching, the harder the steel becomes.

Recrystalization: The process by which a metal changes from a liquid to a solid state.

Ricasso: The usually flat area of a blade generally above and, or behind the grind of the blade.

Rockwell Test: A test used to determine the hardness of a sample. A machine called a Rockwell Hardness Tester drops a diamond point onto a sample at a given load and measures the depth of penetration. The disadvantage of this test for knife makers is that it measures only hardness, not toughness or wear-resistance.

San Mai: A three layer sandwich consisting of a very hard tool steel core, the outer sides are of softer material that gives great strength, forge-welded together. Can also be of a solid or Damascus core, with a contrasting damascus pattern on the outside.

Scabbard: another term for sheath normally used when discussing larger items like swords and daggers.

Scale: The handle parts on each side of a full tang straight knife or the parts on the sides of a pocket knife or folder.

Scrimshaw: Using a needle or knife point to scratch or cut designs on whalebone or ivory- then applying ink; similar to the process of tattooing.

Slabs: Another name for scales, the flat pieces that are used for the handle of a knife.

Soft Solder: Any of a number of alloys used to join metals. Soft solders have lead and/or tin as a principal ingredient, and melt between 400* & 600*F. A popular variation is made of 96% tin and 4% silver. This is a strong and bright colored solder, but it is not as strong as silver (hard) solder. Soft solder is used in plumbing and electronic applications.

Soldering: The process of joining metal using an alloy called solder. The solder is designed to melt at a temperature lower than the metal it is intended to join. The work and solder are coated with flux and are heated until the solder melts. On cooling, it solidifies to form a firm joint. The terms easy, medium, and hard solder describe solders with progressively higher melting points. Thus, some joints can be made at a relatively low temperature without melting earlier joints made with a higher-melting point solder.

Spheroidizing: A metallurgical technique that uses controlled heating to convert irregularly shaped crystals in steel into ball-shaped particles.

Stainless Steel: The only stainless that will not rust is used in sinks and hospital fittings. Any stainless that will hold an edge will be subject to humidity, salt and acid fluids. (Stainless means just that when applied to knives, it stains less.) This steel contains a larger amount of Chromium which helps retard rusting.

Steel: An alloy of wrought iron and carbon, capable of being hardened by heating and quenching (rapid cooling) in oil. This hardening process could cause brittleness; gently re-heating (tempering) increases the metals resilience.

Stiletto: A dagger with a very slim blade intended for thrusting.

Stock Removal: A general term for the process of shaping knives by selective grinding/filing away of material. It is an alternate method to forging, though stock removal is often used after forging as well.

Swedge: A bevel grind on the edge of the back of a blade.

Tang: The part of the blade that is fastened between scales to make the handle, or goes through a hole in the handle material.

Temper: To soften hard, brittle steel by heating and holding it to a specific temperature without greatly diminishing the toughness and wear resistance of steel.

Toughness: The ability of a metal to resist breaking.

Wear Resistance: The ability of a metal to resist abrasion.

Work-hardening: The hardening of a metal caused by hammering or bending, which often makes the metal too hard to work with until it has been softened by annealing.

Wrought Iron: Pure iron which does not contain any carbon to turn it into steel. Wrought iron is very malleable and easily worked, but can only be hardened by "case-hardening".

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