Pocket Knives 101

Blade Types

Plain Edge

Sometimes called flat ground, a straight edge is the most common, and is formed by grinding the blade in a straight line so it tapers to form a razor sharp edge.




Serrated Edge


Serrated edge knives may also be referred to as wavy or scalloped edge. Serrated edge knives feature teeth along the blade edge, which easily penetrate the tough outer crust or skin of the product being cut while protecting the soft inner part from tearing. Serrated edge knives are ideal for cutting bread and fruit. 

ComboEdge

ComboEdge knives are simply half Straight Edge and Half Serrated. The Straight Edge being toward the point or belly of the blade and the Serrated Edge being at the heel of the blade. These versatile knives offer the combined performance from the two most popular edge types. 

Common Edge Types

 Straight or “V” Ground

This is the most common edge type available. It is a double-edge symmetrical flat grind that is easy to sharpen and maintain. It is a great general purpose edge.

Hollow Ground Edge

Hollow ground edges are created by grinding from just below the midpoint of the blade to form concave sides that come to a very thin cutting edge. Since this edge is so thin, it is more brittle and easily dulled. Hollow ground edges are not preferable for heavy cutting tasks, but are ideal for fine cutting. 

Compound Edge

Compound Edge is double-edge double grind with each grind tapering slightly different from point to heel. This creates a more durable edge but sacrifices some sharpness. It is used on blades made with softer steels to decrease wear. 

Chisel Edge

Chisel Edge is a single-edge grind which is usually the sharpest available. It sacrifices some durability and needs to be sharpened more often but sharpening is easier because only the ground edge needs to be sharpened.  

Point Types

Straightback


Straightback blade has a curving edge, and flat back. A dull back lets the wielder use fingers to concentrate force; it also makes the knife heavy and strong for its size. The curve concentrates force on a small point, making cutting easier. This knife can chop as well as pick and slice.

Curved


Curved, trailing-point knife has a back edge that curves upward. This lets a lightweight knife have a larger curve on its edge. Such a knife is optimized for slicing or slashing. Trailing point blades provide a larger cutting area, or belly, and are common on skinning knives.

Clip-Point


Clip-Point blade is like a normal blade with the back "clipped" or concavely formed to make the tip thinner and sharper. The back edge of the clip may have a false edge that could be sharpened to make a second edge. The Bowie knife has a clipped blade and clip-points are quite common on pocket knives and other folding knives.

Drop-Point


Drop-Point blade has a convex curve of the back towards the point. It handles much like the clip-point through with a stronger point less suitable for piercing. Swiss army pocket knives often have drop-points on their larger blades.

Spear-Point

Spear-Point blade is a symmetrical blade with a spine that runs along the middle of the blade. The point is in line with the spine. Spear-points may be single-edged (with a false edge) or double-edged or may have only a portion of the second edge sharpened. Some throwing knives may have spear-points but without the spine, being only flat pieces of metal.

Stiletto


Stiletto blade is a symmetrical, highly tapered, twin-edged blade. Its long, narrow point offers good penetration but is liable to breakage if abused. Although often referred to as a knife, this design may also be referred to as a Dagger or Needle-Point due to its use as a stabbing weapon.

Tanto-Point

Tanto-Point style knife has a somewhat chisel-like point that is thick towards the point (being close to the spine) and is thus quite strong. It is similar to the points on most Japanese swords. The point is actually a second edge on the end of the blade, with a total edge angle of 60 – 80 degrees.
 

Sheepsfoot


Sheepsfoot or Wharncliffe knife has a straight edge and a straight dull back that curves towards the edge at the end. It gives the most control, because the dull back edge is made to be held by fingers. Sheepsfoot knives are good for whittling and trimming sheep's hooves.

Blade Materials

Stainless Steels 

H1: H1 is a stainless steel which has high nickel content 6-8% and is used for most cutlery stainless steels. This grade has a near immunity to corrosion and tends to bend under extreme conditions rather than break. 

420HC: 420HC stainless is a higher carbon version of AISI 420 and has a relatively high edge stability but low wear resistance. It has a high corrosion resistance and is able to resist rusting even after being left wet for extended periods of time. This material is featured in the Buck Zipper. 

420J2: 420J2 stainless is a low carbon martensitic cutlery stainless steel. It is one of the softest cutlery stainless grades and also has a very low wear resistance due to a low carbide fraction. It is the steel most commonly used in fantasy replica weapons and it is also commonly used as the liner material for folding knives. 

440A: 440A is a stainless steel generally chosen for cutlery which needs high corrosion resistance. It has a higher corrosion resistance than 12C27M and much higher primary carbide fraction and corresponding increase in wear resistance and decrease in edge stability.

 440B: 440B has an increased hardness and carbide fraction than 440A and thus offers a higher wear resistance but lower edge stability. It also has a lower corrosion resistance and toughness. It can also be considered to be a high wear resistance upgrade to 12C27M with reduced edge stability and toughness. 

440C: 440C has an increased hardness and carbide fraction over 440B and thus offers a higher wear resistance but lower edge stability. 440C can be considered to be a high wear upgrade to 12C27 where a high edge stability isn't desired. However for this purpose, other alloys are generally regarded as superior such as 154CM.

 154CM: 154CM/ATS-34 is a high carbon stainless steel generally regarded as a direct upgrade to 440C. It has a high wear resistance for a stainless steel and a low edge stability. It is one of the more brittle stainless steels and in general works best on smaller blades intended for extended aggressive slicing. 

INOX: The steel used in Swiss Army Knives is referred to as INOX which in general means simply stainless steel. This particular blend has a composition similar to 12C27M having a slightly higher chromium and molybdenum. The Swiss Army knife blades would therefore be expected to have a very minor slightly higher wear and corrosion resistance but lower hardening response. 

12C27: 12C27 would work well in knives which don't need the extreme corrosion resistance of 12C27M and are also willing to trade some toughness for a higher hardness and wear resistance. 

12C27M: 12C27M is a Sandvik stainless steel designed for kitchen cutlery. It has significantly lower wear resistance but a high edge stability and maximal sharpness through the a lower fraction of undissolved carbides. 

13C26: 13C26 is a natural upgrade to 12C27 where a higher hardness and wear resistance are required and the higher corrosion resistance and toughness of 12C27 isn't needed. As 13C26 is designed as a razor blade steel it sets a high standard for edge stability and is thus an ideal stainless steel for those who desire a high initial sharpness and keep their blades very sharp. 

8C13CrMoV: 8C13CrMoV is basically an upgrade to 13C26 in terms of wear resistance while reducing edge stability. Thus it offers better extended slicing aggression though lower optimal push cutting sharpness and high sharpness edge retention. 

AUS-4A: AUS-4A has a slightly lower hardness and wear resistance than 420HC with a slightly higher corrosion resistance thus it is would be best suited to knives with very high demands on toughness and corrosion resistance. 

AUS-6A: AUS-6A can be considered to be a high edge stability version of 440C. It actually has a fairly high maximum hardness due to the low chromium content, however due to how it is usually hardened in production knives it is mostly suitable for a fairly tough utility knife with little regard for cutting performance. 

AUS-8A: AUS-8A falls almost directly in between 12C27 and 13C26 in regards to hardness and corrosion resistance and would basically be an intermediate step in that progression. In most knives it is ran very soft so it tends to function as more of a tough knife than a cutting tool. 

VG-10: VG-10 is a high wear stainless steel in the same class as 154CM however has better edge stability and offers superior corrosion resistance and extended edge retention. 

BG-42: BG-42 is a very high purity, high wear, martensitic stainless steel which offers very high heat resistance. The hot hardness is likely not of significant benefit for knife blades but the other attributes often causing it to be highly praised among discriminating users. It is generally regarded to be in the same class as 154CM but better in most respects for cutlery. 

SGPS: SGPS is a powder metallurgy steel which is in the same class as S30V as a high wear alternative to 154CM. 

S30V: S30V is a powder metallurgy martensitic stainless steel made by Crucible. It has a high wear resistance which gives it high slicing edge retention on abrasive materials such as cardboard. It performs very high in regards to slicing aggression edge retention.

 S90V: S90V is a powder metallurgy martensitic stainless steel made by Crucible. It has an extremely high wear resistance which gives it high slicing edge retention on abrasive materials such as cardboard. 

ZDP-189: ZDP-189 is a powder metallurgy martensitic stainless steel made by Hitachi Metals. ZDP-189 is mainly promoted for the very high hardness 66/67 HRC which is rare in stainless steels.


Tool Steels 

L6: The material properties of L6 are very well suited to large blades as it is a very tough steel, and can also be readily heat treated to form bainite which is much tougher than martensite at similar hardness. 

O1: O1 is a general purpose tool steel known for moderate wear resistance and toughness and low corrosion resistance. It makes a very nice light utility knife. Its performance in larger knives is not as impressive. 

A2: A2 is an air hardening tool steel known for a solid combination of wear resistance and toughness. It can be very brittle. 

D2: D2 is a tool steel known for high wear resistance through its very heavy chromium carbide content and high obtainable hardness. In general it makes an excellent steel for fine cutting blades, at moderate sharpening angles, and especially for coarse finishes. The corrosion resistance is high for a type of tool steel, though it tends to pit readily in salt water soaks, and the resistance to impact is also low. 

INFI: INFI is a tool steel known for overall solid performance with a excellent balance of corrosion resistance, toughness and edge retention. It makes a superb large blade as well as smaller blades which need to handle tougher work. 

M2: M2 is a HSS tool steel which high obtainable hardness and wear resistance with low impact toughness. It has a very fine grain structure and makes an excellent low impact cutting knife. The corrosion resistance is lower than stainless cutlery steels but high in general for a tool steel. 

CPM-3V: The CPM-3V material is a good combination of high toughness and wear resistance. 

CPM-10V: CPM-10V makes an excellent choice for a knife which is designed as a cutting tool. It takes a very sharp edge easily and will hold it well for a long time resisting wear and deformation very well. 

CPM-15V: CPM-15V offers extreme wear resistance and very high hardness and thus makes an excellent choice for a light use cutting knife. The machinability is low which is common for high wear steels so the edge profile should be minimized for ease of sharpening.

Carbon and Alloy Steels 

1095: 1095 is a high carbon steel, usually water quenched. It can reach 66 HRC and has moderate wear resistance and good to high impact toughness. It is ideal for knives made from thin stock. 

52100: 52100 is advocated by some as an ideal blade steel, very fine grained with a solid combination of edge retention over a wide range of materials due to its combination of hardness, wear resistance and toughness. 

50100-B: 50100-B is one of the more common carbon steels in the cutlery industry, however it is rarely called by that name. Cold Steel calls it Carbon V, Case calls it "chrome vanadium". It is basically a low alloy enhancement of 1095 designed to give deeper hardening, refine the grain and as well provide slight increases to wear resistance and corrosion resistance.

Handle Materials

Natural 

Stabilized Wood: Select hardwood veneers are vacuum impregnated with special dyes and resins. Sheets are layered and combined under tremendous heat and pressure to adhere the veneers for a durable real wood medium. 

Bone - Bone used for knife handles is taken from naturally deceased animals. Bone handles are usually given a surface texture for better grip and added beauty. Each of the patterns has its own distinguished look and can be dyed in variety of colors. Bone is a very good material for knife handles as it is durable, fairly easy to shape and can be very attractive. It is one of the most common handle material used for pocketknives.

 Leather - Leather handles are seen on some hunting and military knives. Leather handles are typically produced by stacking leather washers, or less commonly, as a sleeve surrounding another handle material. Leather knife handles are attractive to look at but are not as durable as some other materials. Leather works well as spacers to add accents to a knife handle. 

Abalone - Abalone is a natural material from the shell of a mollusk that is harvested off of the coast of California, Mexico and other areas of the South Pacific. It has a very pleasing appearance but it is not as durable as some other knife handle materials. Its most popular use is for gentlemen’s pocket knives where it would not be exposed to the rough and tumble of heavy duty outdoor use. There is also an imitation abalone made from a type of plastic which is used mainly for pocket knife handles. 

Black Mother of Pearl - Blacklip Mother of Pearl is one of the most exclusive pearls in demand in today's knife market. It comes from small shells found in French Polynesia around Tahiti and its Archipelagos. Just under the exterior bark of the shell is where the real beauty of the Blacklip shell lies. It is very similar to abalone from the standpoint of durability and uses. 

White Mother of Pearl - A highly prized knife handle material! White Mother of Pearl comes from the silver lip shell. Some of the best White Mother of Pearl comes from the South Seas of tropical Australia. It is very rare in sizes large enough to use for knife scales. It is said that it takes 10 tons of pearl shells to find material large enough to cut scales of 1/10” x 4 1/2” long. It is also very similar to abalone from the standpoint of durability and uses. 

Stag - Stag is another material that is extremely popular. Of all of the deer species, Sambar Stag antler material is the most sought after for knife handles because it is denser than the others. The charm of stag comes from the attractive looks and rough texture of the surface that gives a nice grip for the user. Another intriguing thing about stag knife handles is that, since it is a natural material, no two knives will be alike. Stag is derived from naturally shed deer antlers. Stag is very durable and it makes excellent knife handle material. 

Manufactured 

6061 T-6 ALUMINUM: A nonferrous metal originally developed as a premium aircraft grade aluminum, it offers a solid handle form and function at a nominal weight. 

CARBON FIBER: A contemporary, premium composite of thin strands of carbon tightly woven into various weave patterns, then set in resin, which is most commonly clear but can be color tinted. It offers great looks and is exceptionally strong for its minimal weight. 

DELRIN®: A lightweight and durable engineered polymer with low wear properties. Used throughout the auto industry. 

FRN: Injection-molded glass-filled nylon. Lightweight and durable, FRN is usually cast directly over the handle liner as an overlay. 

G10: An extremely durable makeup of layers of fiberglass soaked in resin, then highly compressed and baked. It is Impervious to moisture or liquid and physically stable under climate change. Most commonly black, but is available in various colors, too.

HYTREL®: Hytrel® thermoplastic polyester elastomers provide the flexibility of rubbers, the strength of plastics, and the processibility of thermoplastics. 

KRATON®: A thermoplastic elastomer offering excellent flexibility and memory elasticity even under harsh conditions. It is over-molded onto the handle for added grip surface and tactile qualities. 

KYDEX®: A mixture of acrylic and PVC, which offers outstanding impact and chemical resistance as well as fire retardancy. Widely used in the auto and aerospace industry. 

MICARTA: Layers of linen cloths soaked in resin and pressured together. Most commonly used on more stylish knives due to its rich color finish qualities. 

NORYL GTX®: A modern engineered plastic offering high-strength, minimal flex and optimally lightweight properties. 

PHENOLIC: A resin based material strengthened with natural or glass fibers (Fiberglass), similar to Bakelite.

POLYIMIDE: Polyimides are a very interesting group of incredibly strong and astoundingly heat and chemical resistant polymers (Plastic). Their strength and heat and chemical resistance are so great that these materials often replace glass and metals, such as steel, in many demanding industrial applications. 

POM: Acetal (POM) Homopolymer -  See Delrin®

THERMORUN®: Themorun is a high performance Thermoplastic Elastomer, a type of rubberized plastic, derived from synthetic rubber. Material is lightweight and very durable. It has a good resistance to heat aging, water, weather, ozone, and chemicals. 

VALOX®: A reinforced resin with excellent stiffness, strength and dimensional stability. 

ZYTEL®: A lightweight glass filled nylon engineered for strength and durability. Widely used throughout the auto industry in engine related components. 

Blade Lock Types

Slip-Joint
Found most commonly on traditional pocket knives, the opened blade does not actually lock in a solid position but is held in place by a spring device that allows the blade to fold if a certain amount of pressure is applied.


 

Lockback
A "Lockback" is a type of folding knife that locks open. Locking folders provide much of the confidence of a fixed-blade while open, yet enable you to fold the blade for safety and carrying convenience. Opening the blade causes the "rocker" to lock against the blade so it locks open. Pushing down on the rocker at the back of the handle releases it and enables you to close the blade. Lockbacks require two- hand closing, though some are one-hand openers. 

Liner Lock

The “Liner Lock” is one of the most common today on knives, especially so-called "tactical" folders. Its main advantage is that it allows one to disengage the lock with one hand. It consists of a liner bent so that when the blade opens, the liner presses against the rear of the tang, preventing it from swinging back. To disengage, you press the liner to the side of the knife from where it is attached to the inside of the scales. 

Frame Lock

A "Frame Lock" operates like a liner lock, only the lock is a tensioned part of the handle frame with an open channel. When the blade opens, the frame lock moves into the handle opening and locks against the blade. Pushing to the left releases it from its "locked" position so you can close the blade.


Ball Bearing Lock

The ball bearing used in the lock sits on two springs that push it forward above the blade’s tang and locking the blade open. High-tech yet simple, the round bearing rotates, rolling in its housing never wearing at exactly the same spot. It self adjusts as the knife is repeatedly opened and closed, minimizing wear and tear.

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