Glossary of knife materials and manufacturing terms

The beauty of a quality blade is how simple it looks. Yet the materials that go into creating a strong blade with good edge-retention is quite involved.

Alloy steel

Steel that has been enhanced with additional elements (chromium, molybdenum, vanadium, nickel) is called alloy steel.

Back

The back of the blade is the opposite side of the belly, for single edged pocket or bowie knives this would be the unsharpened side. The back can contain lashing grommets, jimping, it’s own edge or false edge, and serrations.

Belly

The belly is the curving part of the blade edge. Bellies enhance slicing and may be plain or serrated. One note, the point of the knife becomes less sharp the larger the belly is. When choosing a knife you should decide whether penetration or slicing is the most important, and keep the design of this part of the knife in mind.

Bevel

The bevel is the sloping area(s) that fall from the spine towards the edge and false edge of the blade.

Blade; Blade steels

AUS-8; 8A

A fairly good grade of knife steel, AUS-8 steel has a moderate carbon content and thus reasonable edge retention and mediocre corrosion resistance. This is the steel often used in a kitchen cutlery knives Set. See also stainless steel.

ATS-34

Premium grade of stainless steel used by most custom knife makers and upper echelon factory knives. Also common with the making of quality tactical folding knives or production collectible pocket knives. It is Japanese steel, owned by Hitachi Steels. The American made equivalent of ATS-34 is 154CM, a steel popularized by renowned maker Bob Loveless.

GIN-1

Another low cost steel, but slightly softer than AUS-8; Also referred to as G2

CPM-T440V

CPM-T440V has been claimed as a “super steel”, it outlasts all stainless steels on the market today. It is, however, harder to resharpen (due to its unprecedented edge retention). But the tradeoff is that you do not have to sharpen as frequently. CPM-T440V is widely used by custom knife makers and is slowly finding its way into high-end or gentlemen’s folding knives.

SAN MAI III

San Mai means “three layers”. It’s the term given to the traditional laminated blades used by the Japanese for swords and daggers. Laminated construction is important because it allows different grades of steel to be combined in a single blade. A simple way to think of this type of construction is to imagine a sandwich: The meat center is hard, high carbon steel and the pieces of bread on either side are the lower-carbon, tough side panels.

420J2

This steel has a low carbon content, but its hardness is a little better than basic 420 steel, reaching a max of about Rc 56 to 58. Knives with 420J2 steel will display great corrosion resistance and moderate edge retention. This would be a low maintenance knife ideal for basic outdoor use.

Due to its low carbon high chromium content this steel is an excellent choice for making tough (bends instead of breaking), shock absorbing knife blades with excellent resistance to corrosion and moderate edge holding ability. It is an ideal candidate for knife blades that will be subject to a wide variety of environmental conditions including high temperature, humidity, and airborne corrosives such as salt in a marine environment. This extreme resistance to corrosion via its high chrome content also makes it a perfect choice for knife blades which are carried close to the body or in a pocket and blades which will receive little or no care or maintenance.

Carbon V

Carbon V steel is a very clean, fine grained material with a high carbon content for toughness and response to heat treatment. Excels in edge holding ability.

S30V

Revolutionary S30V steel blades are harder, more wear resistant and far less brittle than any standard 440C series stainless steel blade. Tests also show 45% better edge retention than 440C stainless.

Titanium

Titanium knives are almost completely rustproof and corrosion resistant because they contain no carbon. The result is a knife that will hold an edge for a very long time. Titanium steel knives require almost no sharpening or maintenance.

Butt

Also referred to as the pommel. The very end of a bowie knife. Many butts and pommels are designed for hammering or bonecrushing. Other butts and pommels are decorative and can contain a lanyard hole. Some knife pommels and butts butts are designed are removable so additional items can be stored in the knife handle.

Carbon

An element present in all steels. More carbon increases hardness.

Choil

The unsharpened part of the blade. The choil is the full thickness of the blade where the blade meets the handle.

Chromium

A major element in martensitic stainless steel. It improves hardenability, wear and corrosion resistance.

Clasp

A type of folding knife that has no lock or backspring.

Coils

Long steel strips that come in large rolls are fed into a Fine Blanking press, which is the first step toward making a blade.

Corrosion resistance

A blade’s ability to resist rust, which is the result of exposure to the environment or elements.

Crink

A bend at the beginning of the tang that keeps multi-bladed pocket knives from rubbing against each other.

Drop Forged

Closed die forging. The form of the finished item is built into the die, the steel is heated and the hammer forms the plastic steel into the recesses of the die.

Drop Point

A knife blade that slopes on the spine of the blade from the handle of the knife to the tip of the blade. This allows the spine of the blade to continue forward to the tip of the blade. The curve is always convex and is a common design for hunting knives.

Ductility

The blade’s ability to flex, bend or take an impact without fracturing. If the amount of flex or bend is small before cracking or breaking, the blade is considered brittle.

Edge

The sharpened side of the blade. Single and double edged (dagger style).

Edge retention

A measure of the blade’s ability to hold an edge by resisting abrasion and wear. We use the CATRA machine, a computer-controlled testing machine that gives the most accurate and repeatable data for an objective evaluation of edge sharpness and consistency.

Escutcheon

A small pin or metal piece attached to the handle for decoration, engraving or branding.

False Edge

An additional bevel on the back of a knife blade to enhance the blade’s point. Is commonly found on military and combat knives, the false edge can be used for heavy cutting.

Fine blanking

Process used to press a knife blade out of a coil of steel using a specifically shaped die. This process produces consistently accurate parts requiring little additional machining. Used in Buck Knives.

Game hook

See gut hook

Gut hook

A knife blade shape best utilized for opening the flesh of game.

Hardenability

The steel’s ability to be hardened.

Hardness

A good indicator of the steel’s ability to hold an edge. A blade’s hardness is measured on the Rockwell “C” scale, a testing process described in Making a Knife.

Heat-treat

An important series of steps in developing blade properties, such as toughness.

(HRC) Rockwell Hardness

See Rockwell.

Hydralloy

A type of stainless steel developed by UK Underwater Kinetics intended especially for underwater scuba and diving conditions. Hydralloy utilizes a unique blend of metal alloys and proprietary finishing techniques to provide a knife with the strength of 420 Stainless Steel, while exceeding the corrosion resistance of 316 Stainless Steel.

Initial sharpness

The sharpness of the blade right “out of the box,” and the sharpness that is the goal when re-sharpening.

Jimping

Also known as Lashing Grommets. The notches in the back lower blade of some knives to provide better thumb control of the knife.

Kick

The Knife Kick is commonly found on pocket knives. It is the piece on the front edge of the tang that the blade rests on in the closed position to keep the front part of the edge from hitting the spring.

Lanyard, Lanyard hole

A hole usually in the knife handle to fit a lanyard or rope for convenient carry.

Laser cutting

Large blades and “hard steel” blades are cut from sheets of steel using a state-of-the-art computer-controlled laser that can cut out blades to a specified shape.

Lashing Grommets

See Jimping.

Manufacturability

The ease in which steel can be machined, blanked, ground and heat-treated.

Martensitic

Steel that is capable of being brought to a very hard condition is called martensitic steel. This steel is best suited for knife blades. See Heat-Treating.

Molybdenum

An element added to steel to improve hardenability, tensile strength and resistance to corrosion and pitting.

Nickel

An alloy addition that improves steel’s toughness, hardenability and corrosion resistance. Nickel is a major element in steel used for kitchen cutlery and dive knives.

Plate

Flat sheets of steel that are turned into knife blades by laser cutting.

Pommel

See Butt.

Properties

Refers to such things as hardenability, ductility and toughness, which are established by the particular chemistry of the steel and the proper heat-treat process. Properties most important to knife blades are covered in this glossary.

Rockwell

A hardness-testing machine that forces a small penetrator into the surface. The depth of penetration correlates to a scale reading, the scale normally used for knife blades is the “C” scale written as “Rc”. The higher the number, the harder the steel. Most blade steels are in the range of Rc 58-61. Buck maintains an Rc 58 on standard steel. Our higher end steels range from Rc 59-61, depending on use.

Stainless steel

The common term “stainless” is misleading. More accurately, it should be called “stains less” because it is not “stain free.” In certain environments, any steel with carbon will rust. Stainless steel’s corrosion-resistant properties make it a good material for knife blades.

Steel is made “stainless” by adding chromium and reducing its carbon content during the smelting process. Some authorities claim that there is a serious performance trade off with stainless steel: As the Chrome increases and the Carbon decreases, the steel becomes more “stainless”. But it also becomes more and more difficult to sharpen and, some claim, the edge-holding potential is seriously impaired. Generally speaking stainless steel blades are as sharp as other material blades and hold the edge longer. AUS 8A is a high carbon, low chromium stainless steel that has proven, over time, to be a very good compromise between toughness, strength, edge holding and resistance to corrosion.

Types of stainless steels include: 420, 440A, 440B, 440C, 440V, ATS-34, Hydralloy

Strength

Steel’s ability to resist applied forces.

Tempering

The final step in the heat-treat process to improve toughness.

Tensile strength

Ability to resist breaking. Ultimate Tensile Strength is the maximum load per square inch a blade can sustain before breaking.

Toughness

A blade’s ability to absorb energy by impact prior to fracturing.

Vanadium

A material added to steel to improve hardenability and promote fine grain, which is an important factor in wear resistance.