Friday, August 26, 2005

Knife Glossary

Knife Glossary

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 Spine - This is the thickest part of a blade. On a single-edge, flat-ground bowie knife, the blade spine would be at the back of the blade. For double-edged blades, the blade spine would be found right down the middle.

Butt/Pommel - The butt, or the pommel is the very end of the bowie knife. The butt/pommel will be found in different shapes, depending on what features it was designed to implement. Some flat metal butts/pommels are good for hammering. There are pointed metal butts/pommels, known as bonecrusher pommels used on combat fighting knives, combat tactical knives, combat survival knives and large bowie knives. They can be decorative, or contain a lanyard hole. Some butt/pommels are designed to be removed to be able to store items in the handle or may contain an additional smaller blade or tool.

Butt Cap - A metal cap fitted over the pommel is referred to as a butt cap.

Choil - The choil is the unsharpened part of the blade. It is left at full thickness like the blade spine and is found where the blade becomes part of the handle. Sometimes the choil will be shaped (An indentation) to accept the index finger. It also allows the full edge of the blade to be sharpened.

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

Edge - This is the sharpened side of the blade. Blades will have a single or double edge (or dagger style) depending on the design.

Escutcheon - this is a small pin or piece of metal attached to the handle for engraving, branding, or just decoration.

False Edge - Widely used on military and combat fighting knives, a false edge blade is an additional bevel on the back of the blade enhancing the blade's point. This edge can be sharpened or not. The false edge can also be used for heavier cutting that might be damaging to the cutting edge.

Guard - The guard is a separate piece of metal attached between the blade and the top of the handle to protect hands from the edge during cutting.

Hilt - The entire handle, including the butt/pommel and the guard.

Kick - The kick is found on a pocket knife, usually Boker pocket knives, and is the projection on the front edge of the tang, the blade rests here in the closed position and keep the front part the edge from hitting the spring.

Lanyard Hole - This is a hole to fit a lanyard, rope or carrying implement through.

Lashing Grommets/Jimping - These terms refer to notches that are designed into the back lower part of the blade for better thumb control.

Mark Side - This is another pocket knife term and is the side of the blade with the nail mark.

Nail Mark/Nail Nick - On a pocket knife blade the nail mark is a groove cut into the blade so that it can be opened using your fingernail. Most Case pocket knives use this method of opening the blade.

Obverse Side - The obverse side is the front or display section of a knife.

Point - The tip of the blade. For more information see Blade Shapes.

Pile Side - The reverse side of the blade, opposite of the obverse side.

Pocket Blade - This is the largest blade on a multi-bladed knife.

Pen Blade - The pen blade is the smallest blade on a multi-bladed knife.
I am told this PEN BLADE is named for its shape and size, so I am adding this correction in a different color, Thanks to Terry Murbach.

Quillon - The quillon is the area of the guard that extends past the section surrounding the tang and is the most protective part of the guard.

Ricasso - The ricasso is the flat section of the blade between the guard and the start of the bevel. This is where you will most often find the tang stamp.

Scales - The scales are pieces that are attached to a full tang to form the handle.

Scrimshaw - Scrimshaw is the art of etching decorative designs into ivory or simulated ivory handles.

Serrated Edge - Serrations are a set of "teeth" or notches on the back or front of the blade to aid in cutting.

Swedge - A swedge is a bevel on the back of the blades.

Tang-Stamp - This is an imprinting that can show style number, collector's number, manufacturer's name. This is normally located on the ricasso.

Handle Materials STAG Derived from naturally shed deer antlers. When exposed to open flame, stag takes on that slightly burnt look. Very elegant material for pocket knives and gentlemens folding knvies.

BONE Derived from naturally deceased animals. Bone is usually given a surface texture, most commonly in the forms of pickbone and jigged bone. Bone can be dyed to achieve bright colors (e.g. green, blue, and black). This is the most common handle material for pocket knives.

G-10A fiberglass based laminate. Layers of fiberglass cloth are soaked in resin and are compressed and baked. The resulting material is very hard, lightweight, and strong. Surface texture is added in the form of checkering. G-10 is an ideal material for tactical folding knives or fighting knives because of its ruggedness and lightweight. It is usually available in black.

MICARTA The most common form is linen micarta. Similar construction as G-10. The layers of linen cloths are soaked in a phoenolic resin. The end product is a material that is lightweight, strong, as well as having a touch of class (thus dressier than G-10). Micarta has no surface texture, it is extremely smooth to the touch. It is a material that requires hand labor, which translates into a higher priced knife. Micarta is a relatively soft material that can be scratched if not treated properly.

CARBON FIBER Composed of thin strands of carbon, tightly woven in a weave pattern, that are set in resin. It is a highly futuristic looking material with a definite "ahhhh" factor. Of all the lightweight synthetic handle materials, carbon fiber is perhaps the strongest. The main visual attraction of this material is the ability of the carbon strands to reflect light, making the weave pattern highly visible. Carbon fiber is also a labor-intensive material that results in a rather pricey knife such as case collectible knives.

ZYTEL ® Du Pont developed this thermoplastic material. Of all synthetic materials, ZYTEL® is the least expensive to produce, which explains the abundance of work or utility knives that have this material. It is unbreakable: resists impact and abrasions. ZYTEL® has a slight surface texture, but knife companies using this material will add additional, more aggressive surface texture to augment this slight texture. Sog Specialty Knives is common for using zytel.

TITANIUM nonferrous metal alloy, the most common form of titanium is 6AL/4V: 6% aluminum, 4% vanadium, and 90% pure titanium. This is a lightweight metal alloy that offers unsurpassed corrosion resistance of any metal. It has a warm "grip you back" feel and can be finished either by anodizing or bead blasting. Aside from handles, titanium is also used as liner materials for linerlock knives for it is a rather "springy" metal. Titanium is used usually on collectible pocket knives and chef knives.

ALUMINUM Just like titanium, aluminum is also a nonferrous metal. Commonly used as handles, aluminum gives the knife a solid feel, without the extra weight. The most common form of aluminum is T6-6061, a heat treatable grade. The most common finishing process for aluminum is anodizing.

ANODIZATION An electrochemical process which adds color to titanium, which is especially conducive to this coloring process. Depending on the voltage used, colors can vary (high voltage = dark color, low voltage = light color).

BEAD BLASTING A process by which steel, aluminum, and titanium are finished. Bead blasting is commonly found on tactical folding knives and fixed or bowie knife blades, for it provides a 100% subdued, non-glare finish.

1) AUS-8 (also referred to as 8A) (some text courtesy of Boker Knife Company) - Commonly found in a Kitchen Knife Set, the words "stainless steel" are misleading, because, in fact all steel will stain or show discoloration if left in adverse conditions for a sufficient time. 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. We have found that most 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.

2) 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. Boker pocket knives are usually made of ATS-34.

3) GIN-1 - (formerly known as G2) - another low cost steel, but slightly softer than AUS-8.

4) CPM-T440V - currently touted as the "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.

5) SAN MAI III - (text courtesy of Boker Knife Company) An expensive, traditional style Japanese laminate. Hard, high carbon stainless forms the core and edge of the blade, while two layers of tough, spring tempered stainless support and strengthen it. The resulting blade possesses the best qualities of both types of steel. This laminate is 25% stronger than the incredibly tough AUS 8A stainless . The telltale sign of genuine San Mai III is a thin line near the edge that runs the entire length of the blade. This line is created in the grinding process as the layers of steel in the blade are exposed. The distance the line is from the edge varies from knife to knife because every piece of San Mai III steel is unique. Like AUS 8A stainless, San Mai III is treated in modern, precise conveyor furnaces and subjected to a sub zero post hardening process. This improves the microstructure of the steel by eliminating retained austenite. The resulting blades are more elastic and have better edge holding characteristics than standard stainless steels.

6) 420J2 - (text courtesy of Boker Knife Company) 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 excel lent 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 (From Cold Steel) - An exclusive carbon alloy steel, formulated and extensively treated to achieve exceptional properties. Carbon V was developed and refined by using both metallurgical and performance testing. Blades were subjected to the "Cold Steel Challenge" as a practical test, and then they were sectioned, so that their microstructure could be examined.

In this way we arrived at the optimum steel AND the optimum heat treatment sequence to bring out the best in the steel. Cold Steel buys large quantities of premium high carbon cutlery steel with small amounts of elemental alloys added in the smelting stage. These elements enhance the blade's performance in edge holding and elasticity. The steel is then rolled to their exact specifications to establish optimum grain refinement and blades are blanked to take full advantage of the grain direction in the steel.

The blanks are heated in molten salt, quenched in premium oil and tempered in controlled ovens. Then they are ground. The new blades are then subjected to expert heat treatment, involving rigidly controlled austenizing temperatures, precisely defined soak times, proper selection of quenching medium and carefully monitored tempering times and temperatures. This heat treatment sequence results in blades which duplicate and often exceed the properties of the most expensive custom forgings.

Premium U.S. High Carbon (from Cold Steel) - Cold Steel's Premium Carbon Steel is used in a variety of our low cost highly functional knives. Chemical content and microstructure from the mill is specified by Cold Steel and each lot is subjected to the same metallurgical examination before being used in production as our world famous Carbon V. The Steel is a very clean,fine grained material with a high carbon content for toughness and response to heat treatment. Cold Steel has designed a special heat treatment for this material which maximizes toughness in combination with more than acceptable edge holding ability, resulting in a blade which will satisfy even the most discriminating user.

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 - Unlike stainless steel knives, 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.

Blade Shapes Clip Point – A clip point blade has a concave or straight cut-out at the tip (The "clip"). This brings the blade point lower for extra control and enhances the sharpness of the tip. You will often find a false edge with the clip point. These types of blades also often have an abundant belly for better slicing capabilities.

Dagger/Double Edge - A double edge blade is sharpened on both sides ending with the point aligned with the spine, in the middle of the blade.
Drop Point – The drop-point blade has lowered tip via a convex arc. This lowers the point for extra control and also leaves the strength. This type of blade also has a good-sized belly for better slicing.

Hook Blade – The edge of a hook blade curves in a concave manner.

Santuko – Is a Japanese chef’s knife. The spine curves downward to meet the edge and the belly curves slightly.

Scimitar – This is a curved blade with the edge on the convex side.

Sheepsfoot – The spine of this blade curves downward to meet the edge. This leaves virtually no point. This type of blade typically has little or virtually no belly and is used mainly for slicing applications.

Spear Point – The point of this blade is exactly in the center of the blade and both edges are sharpened. The point drops all the way down the center of the blade.

Tanto – The point to this style blade is in line with the spine of the blade. This leaves the point thick and strong. There are quite a few different variations of how tanto blades are designed. The way the front edge meets the bottom edge, whether at an obtuse angle or a curve is one difference. You will also find differences in the point being clipped or not and whether there is a chisel grind.

Trailing Point – The trailing point blade’s point is higher than the spine. This is typically engineered with an extended belly for slicing, with the point up and out of the way.

LOCKING MECHANISMS AND TYPESAxis Lock - The features of the AXIS lock are significant and greatly enhance the function of knives. First and foremost is the strength. This lock is definitely more than adequate for the demands of normal knife use. A close second to strength is the inherent AXIS advantage of being totally ambidextrous without user compromise.

The blade can be readily actuated open or closed with either hand- without ever having to place flesh in the blade path. Lastly, and certainly not any less impressive, is the indescribable "smoothness" with which the mechanism and blade function. By design there are no traditional "friction" parts to the AXIS mechanism, making the action the much smoother. And it's all reasonably exposed so you can easily clean away any unwarranted debris. Basically, AXIS gets its function from a spring-loaded bar that rides forward and back in a slot machined into both liners. The bar extends to both sides of the knife; spanning the space between the liners and is positioned over the rear of the blade. It engages a ramped notch cut into the tang portion of the knife blade when it is opened.

Two omega style springs, one on each liner, give the locking bar its inertia to engage the knife tang, and as a result the tang is wedged solidly between a sizable stop pin and the AXIS bar itself. It's a lot of words in an attempt to describe simplicity, but the very best way to truly appreciate the AXIS lock is to experience it for yourself firsthand. There are several models to choose from with more on the way.

Balisong - Also known as Butterfly Knives. The handle to this style knife is in two separate pieces and pinned to the tang. A third pin fixes between both sides to lock the blade into an open position. offers a wide selection of Butterfly Knives for sale.
Block Lock - This folder lock has a spring loaded block located on the center pin. The block extends into a hole in the tang to lock the blade open.

Clasp - This style folding knife has no lock or backspring.

Lockback - This style of lock has a spring-loaded locking bar with a tooth at the end. The tooth falls into the notch cut into the blade tang and is held there under the spring tension. A cut out in the handle spine houses the release for the lock. These locks generally require 2 hands to unlock and close.

Locking Liner - (a.k.a. linerlocks) This particular locking system was refined by knife maker Michael Walker. The actual locking mechanism is incorporated in the liner of the handle, hence the name. If there is a metal sheet inside the handle material, it is called a liner. With a locking liner, opening the blade will allow this metal to flex over and butt against the base of the blade inside the handle, locking it open. Moving this liner aside will release this lock allowing the blade to close. Disengagement of the lock is performed with the thumb, allowing for one handed, hassle free action. Locking liners are commonly found on tactical folding knives, both production and custom.

Ringlock - This design has been around since the 1890's. The Ringlock is similar to the Slipjoint, but it has a rotating slipring instead of a backspring.

Rolling Lock - This design uses a sort of bearing that rolls into the locked position.

Sebenza Lock - The concept of this lock is comparable to the Liner Lock. A hollowed out section of the scale is fixed into the handle cavity to lock the blade open.

Slipjoint - The slipjoint is one of the more common designs for folding and pocket knives. Instead of a lock, the slipjoint utilizes a backspring to create resistance to hold the blade open.

Swinglock - There is one pivot pin and one locking pin used to design this style lock.

Wood Lock - This lock was designed by Barry Wood. The handles and blade are attached to a central pin and pivot independently. A second pin is fixed into the inside of one scale and extends into slot in the tang to lock the blade open.

1) HOLLOW GRIND - The most common grind, found on the majority of custom and production pieces. Hollow ground blades have a thin edge that continues upwards, and is the grind is produced on both sides of the blade. Since the cutting edge is relatively thin, there is very little drag when cutting. Examples of knives with hollow ground blades: Spyderco Howard Viele C42 and Kershaw Ti-ATS-34.

2) FLAT GRIND - Flat grinds are characterized by the tapering of the blade from the spine down to the cutting edge. This style of grind is also referred to as a "V" grind, since the cross section of this grind resembles that letter. The chisel grind, a popular style for tactical blades, is a variation of the flat grind. On a chisel round blade, it is ground on one side, and on the other it is not.

These blades are easier to sharpen, because you sharpen one side only. Example of a knife with a chisel ground blade would be the Benchmade 970 Ernest Emerson CQC7. Examples of knives with a flat grind are the Benchmade Mel Pardue 850 and Spyderco's C36 Military model.

3) CONCAVE GRIND - Similar to the flat grind in that the blade tapers from the spine to the cutting edge, except the taper lines are arcs instead of straight lines.

4) CONVEX GRIND - Similar to the flat grind in that the blade tapers from the spine to the cutting edge, except the taper lines are arcs extending outward instead of inward as in the convex grind above or straight lines. If you picture a pumpkin seed, you will get a good idea of what the cross sectional view of this grind is like. Noted custom knife maker Bill Moran is credited for bringing the convex grind into the focus of knife making.

Chisel - The chisel grind is ground on only one side of the blade. It’s easy to produce and easy to sharpen. It is often ground at around 30 degrees which contributes to a thin and sharp edge.

Sabre - The sabre grind has flat edge bevels that typically begin about the middle part of the blade and runs flatly to the edge. The edge is often left thick and thickens quickly past the edge. This is a great grind for chopping and other hard uses.

Scandinavian Single - Bevel the Scandinavian single-bevel grind looks similar to a sabre grind. The difference between the two grinds is that the Scandinavian single-bevel grind has no secondary edge bevels. This grind has an extremely thin and incredibly sharp edge.

Sunday, August 21, 2005

Knife Facts

Knife Steel Facts
Written by Byron Rogers

Knife Steel

By definition, steel is a combination of iron and no more than 2% carbon.

Which Steels For Which Knives?

Heat treatment is as crucial a part as the grade of steel.
Basically, knife steels are high carbon stainless or non-stainless high carbon.
High carbon stainless is rust resistant though harder to sharpen.
Non-stainless high carbon rusts easier but is easier to sharpen.
With proper heat treatment, 440 should hold an edge slightly better and sharpen a bit easier than the lower 400 series stainless.
The lower 400 series stainless are gaining in popularity among the factories because they cause less wear on tooling.
ATS-34 and CPM 440V cost more than the other stainless steels, and the CPM 440V costs the most.
Blades of most stainless steels used in knives are not rustproof but are rust or stain resistance. So therefore stainless steel blades should still be kept clean and wiped dry after use, especially many of the new high carbon stainless steels like ATS-34, and CMP-T440V. But they do not need as much care as carbon steel knives.
Attributes and Best Applications of Stainless Steels In Knife Manufacturing*

Steel Type
Best Applications

Superior edge-holding & stronger than 440
Pocket knives - hunting knives

Strongest but doesn't cut that well
Rough use knives - throwers

3rd best of 440 types in edge holding
General purpose knives

2nd best of 440 types in edge holding
General purpose knives

Best of 440 types in edge holding
Most all knife types

CPM 440V
Best edge holding stainless of all
Pocket knives - hunting knives

Similar to 440C; may be stronger
Most all knife types

Similar to 440A; may be stronger
General purpose knives & fighters

Similar to 6A
General purpose knives

* This assumes the steel is properly heat treated. ** Few factories use 440B steel anymore.

Article by Copyright © Byron Rogers, visit for more original content like this. Reprint permission granted with this footer included.

Knives in ENGLAND


The Offensive Weapons Act 1996 means that you can go be sentenced to imprisonment for up to two years and/or be fined if you are carrying a knife in public without a good reason. The police can arrest people on the streets who are committing this offence.

People can go to prison for four years and/or be fined if they are carrying an offensive weapon in public without good reason.
From September 1996 it became a criminal offence to carry a knife or an offensive weapon on school premises, with a maximum penalty of two years imprisonment and/or be fined.

From 1 January 1997 it became a criminal offence to sell a knife to a person aged under 16, with a maximum of six months imprisonment or a fine or both.

Other laws covering the carrying of knives include:

A flick knife is any knife which has a blade which opens automatically by hand pressure applied to a button, spring or other device in or attached to the handle.

A gravity knife is any knife which has a blade which is released from the handle by the force or gravity or the application of centrifugal force.

Knives Act 1997
Sections 1 - 7 and 9 - 10 came into effect on 1 Sept 77 and is aimed at tackling the menace of combat knives and the knife culture and bans the aggressive marketing of knives.

The act now makes it an offence to advertise a knife or offer it for sale in a way which suggests it could be used for combat or to encourage violent behaviour. The maximum penalty for this is new offence will be six months imprisonment and/or a £5000 fine. The controls are aimed at ensuing that knives ,which can cause serious or fatal injuries are not offered for sale or marketed in a way appears to condone violence. .

Other provisions include :-

Powers for courts to issue a warrant for the police to enter premises of
someone suspected of marketing knives for aggressive use.
Powers for the courts to order the forfeiture of knives or publications by a person convicted of the offence.

Section 8 of the act relating to police powers of stop and search will be brought into force at a later date.

Knives: questions and answers

Q. Can I carry a knife with me?

A . Not unless you have a good reason to - for example, to use at work, for religious purposes or as part of a national costume. There are very few good reasons for youngsters to carry knives. If the police prosecute you for carrying a knife in public or at school, you will have to prove that you were carrying if for a good reason.

Q. Why can’t I carry a knife?

A. A knife in the wrong hands can be used to maim or even kill, which means that the law has to be very strict on the carrying of knives.

Q. Can I buy a knife?

A. From January 1, a shopkeeper will be breaking the law if he sells a knife to anyone under 16

Q. How old do I have to be to carry a knife?

A: It does not matter what age you are, the police may charge you with a very serious offence if you haven’t got a good reason.

Q. What if I carry a small pocket knife?

A: If the blade is under 7.6cm (3 inch) you will not be charged with simple possession. But if the police believe that you are carrying it as an offensive weapon they can prosecute you under a different law.

Q. What would happen if I do carry a knife?

A. If you do not have a good reason to be carrying it (see Q1), a court may find that you have committed a serious criminal offence.

Q. Can I go to prison just for carrying a knife?

A. Yes, for up to two years.

Q. Is it only knives, or are there other sharp things I am not allowed to carry?

A. It is an offence to carry an article with a blade or sharp point in public or at school without good reason.

Q. I can use knives in the kitchen, so why can’t I use them outside the house?

A. You can. The offence, under section 139 of the Criminal Justice Act 1988, is that of carrying a knife in public without good reason (see Q1).

Q. What if I have to buy a kitchen knife from a shop for my Mum/Dad?

A. From 1 January, if you are under 16 you will not be able to do this. The best thing is to have a responsible adult with you if you are making such a purchase.

Q. What should I do if I see/know of someone/a friend carrying a knife?

A. The police will take the details from you and pass them to our information unit.

Q. Can I carry a knife to protect myself from people who attack me in the street?

A. No. The law does not allow you to carry a knife or any other weapon for self-defence.

Q. I can hide my knife in my pocket and the police won’t even know I have got it, so how can they stop me?

A. The police have special powers to stop and search people for knives, and the Home Secretary has said that he is going to make these powers even wider. Hiding a knife provides no real protection against being caught.

Q. I have some kitchen knives to dispose of what do I do with them?

A. There are no set instructions but a good method is to wrap the blade in several sheets of newspaper and place it in the dustbin on the day it is due to be emptied, however individual local authorities may have there own set procedures/methods, if you need further advice you should telephone your local council

Disclaimer: Nottinghamshire Police has made every effort to try to ensure that the answers given here are accurate. However, due to the complex nature of the law, these answers will not be applicable in all circumstances. Therefore we recommend that these answers be used as a general information guide and Nottinghamshire Police cannot be held liable for this information being used as a substitute for professional legal advice.

Tuesday, August 16, 2005

Knife Steel

by Bob Engnanth

0-1 is perhaps the most forgiving of any knife quality steel other than the very simple alloy types, and produces a blade of excellent quality for most normal use. It can be heat treated very easily. Further references? Well, the ole' master, Cooper, used it for many years and folks do love his blades because they're tough. Awhile back, one of the best of the blade smiths said that well treated 0-1 would out cut any Damascus, and no one argued with him. Edge holding is exceptional. 0-1 is precision ground unless you're lucky enough to stumble across some mill bar. Goof up the heat treat and 0-1 will let you try again as often as you like, as long as you don't overheat the metal. Tough on grinding belts.

0-6 is the next step up from 0-1 easy heat treat but pure hell to grind. It's significantly tougher, with finer crystalline structure and hard graphitic particles that resist wear. Stock is both hot rolled and precision ground. Hot rolled prices are reasonable. Very tough to grind. Edges are incredible, lasting even longer than the best Damascus and even 0-1. Has an odd, rather orange spark.

W-1, W-2, and the series of 10-- steels from 1045 through 1095 are the ultimate in simplicity and very shallow hardening so they may be used to make a selectively hardened edge as one sees on old Japanese swords. Toughness is outstanding, with these alloys being used for grader blade edges, truck springs and files. Uses up grinding belts at quite a rapid rate. Edges are acceptable with 1045, good with 1060, nice with 1084, and excellent with 1095, W-1 or W-2. Those last two are often referred to as O-F, old file. It is very easy to get the higher carbon end of this series way too hard to make a good knife.

5160 is a common spring steel, basically 1060 with one per-cent of chromium added to make it deep hardening. (It may still be selectively drawn with a softer back, if desired.) An excellent steel for swords, or any other blade that will have to take some battering. The choice of Jim Hrisoulas who makes some of the finest working swords in the business. Long blades are best around the mid 50's on the Rockwell scale, while small, working blades can be put into service at a full 60 RC. Forged blades with a well packed edge seem to cut forever! Rough on grinding belts. Jokingly called O-C-S, old chevy spring.

is a ball bearing steel, generally not found in useful grinding sizes, but terrific in edge holding and toughness. 52100 is 5160 with an attitude, more alloy and more carbon that makes it harder and tougher. Like 5160, throws a brilliant yellow spark. Ed Fowler has developed a superior heat treating technique for this steel.

L-6 is the band or circular saw blade steel used in most lumber mills and downright hard to find in any other form. Hardens in oil to about RC 57 and takes a fine edge for most cutting, particularly where the edge might be steeled back into shape. Outstanding where flexibility is needed but rusts easily, like virtually all of the simple carbon steels. L-7 is the same stuff with a little more carbon.

A-2 is an exceptional steel, with fine wear-resisting qualities plus excellent resistance to annealing and warping. Grinding is noticeably harder than 0-1 but not extremely difficult. Sawing is tougher and relates to the five percent of chrome in this steels chemical make up. Really nice to finish with the grinder and very little grain appearing in buffing. Excellent flexibility. Phil Hartsfield get incredible cutting ability out of this steel. Several other of the A series will also make fine blades.

D-2 offers another air hardening tool steel, but with 12% chrome and excellent, if not superb, wear resistance. The resistance also holds true in both sawing and grinding, even while the steel is fully annealed. While using belts up at a faster rate than average, D-2 is not particularly hard to grind with fresh belts. Using old belts causes enough heat to work harden the steel. D-2 anneals at somewhat higher temperature than A-2 and will not take a true, mirror polish. Definitely a steel for the advanced craftsman. It's major drawback is the orange peel appearance of the surface when finished to a high gloss. One knife maker is often quoted as saying that D-2 takes a lousy edge and holds it forever. Often found as surplus wood plainer blades. D-4 and D-7 are also good cutlery alloys, but darn hard to find in the right sizes. Air hardening steels can work harden while you're grinding them if you get the stock too hot. This doesn't mean much on the grinder, but when you try to file a guard notch, the file will just slide.

M-2 is a high temperature steel made for lath cutting tools, which has darn little to do with knives, but allows you to really cook the blade in finishing after heat treat without annealing it. M-2 is perhaps a bit better in edge holding than D-2. It is also rather brittle and not recommended for large knives.

440C was the first generally accepted knife makers' stainless and remains quite popular, particularly since the sub-zero process was developed to add toughness. On the grinder, it's gummy and gets hot fast, but it cuts a lot faster and easier than any of the carbon steels. Your belts will cut about 2 to 3 times as much 440-C than 0-1. Using hand hacksaws on it will wear out a lot of blades in a hurry. But with the proper care, good heat treating and finishing, 440C produces an excellent, serviceable and durable knife, even for the new knife maker. Anneals at very low temperature. Please note that 440A and 440B are similar alloys, often confused with 440C, but not worth a damn for knife making use. Commercial knife companies often mark blades 440 when they're one of the less desirable versions, giving the real stuff a bad name. 440C is also available in more sizes and in more places than just about any stainless alloy suitable for knives. It is also essential to remember that collectors hate to see one of their prizes turn brown in the sheath, and 440C handles corrosion resistance very well. While the variation, 440-V doesn't seem to get quite as hard, but holds an edge for much longer and is much more difficult to grind.

154 CM was considered by many to be super-steel, if you can find some of the old production stock. The new batches are not manufactured to the standards that we've come to expect for knife steel. While excellent in use, 154 CM eats up the finest hacksaw blades in one across-the-bar cut of 1-1/2". It's machining and grinding qualities are similar to 440C and won't win it any awards for ease in working. In use though, this alloy has a definite advantage in both hardness and toughness over 440C. 154 CM is not an accepted standard grade designation, rather a manufacturers trade name.

ATS-34 Japanese made stainless considered the equal of 154 CM. Import restrictions have been eased somewhat, although they were forced to raise the price by 50%. Cleaner than the 154 CM. (154 CM is no longer used in government specified applications and is not the vacuum melt product that we once appreciated.) ATS-34 is virtually the exact same alloy as 154 CM, minus 0.04% of one of the less essential elements. ATS-34 is double vacuum melted and very clean. It also comes with a hard, black skin that will put a shine on your grinding belt before you know it. We recommend knocking the skin off with old belts before tapering the tang or Vee grinding. One fellow tried to take the skin off with an industrial motor driven wire brush wheel. All he did was polish it. We now stock a belt the is specifically designed to remove this scale. ATS-34
is a trade name. The three, 154 CM, ATS-34 and 440-C, all have a small, reddish spark that has a distinct, but hard to see carbon fork. ATS-34 is also a trade name. That super hard black skin on some of these steels, as well as forging scale, can be "pickled" to remove it. Buy a gallon of inexpensive white vinegar, and leave the steel in it overnight. Works like magic. If it doesn't work, or makes the shop smell like a salad, blame Doug Brack, who gave me this hint.

AEBL seems to be about 440B. Extremely easy to grind, in fact, I think I may have set a world record with it a few years back, over a hundred blades from bar stock to 220 grit within eight hours. Heat treat like 440C. Edge holding is best when heat treating includes a freeze cycle. Very easy to polish and buff. Very nice choice for miniatures, kitchen knives, etc. AEBL has several quirky habits in grinding that make it difficult to use on thicker or larger knives. Makes nice kitchen knives. "Hoss" uses this in his beautiful stainless Damascus and reports that it holds up very well.

420 modified stainless, has been successfully used by some commercial knife producers, but availability is not practical for the hobby knife maker since darn few of us order steel in mill rolls.

VASCO WEAR is rather expensive but very, very good in edge holding. Resists grinding very well too! You'll swear your belts have all gone dull when you try it. Do everything you have to before heat treating, cause you sure aren't going to be able to do much afterward. Priced like lobster tails, when you can find it. Try Vasco-Pacific in the Los Angeles area. Vasco - Pacific uses their own series of names for their alloys.

DAMASCUS steel is such a widely made product that it is impossible to make too many general statements about it, other than it seems to catch collectors better than any other type. Each smith does his in a slightly different way, ranging from the fellow who toughs it out, starting with three layers, to the guy who welds a 300 layer sandwich of shim stock into a billet with one hit in a 40 ton press. They're all pretty. Reese Weiland suggests that the last etch of a Damascus blade be done with phosphoric acid, which will sort of, parkerize the metal and help protect it. He said that you have to play around with the concentration of the acid and immersion times a bit, depending on the steel you're using. This will also work on most carbon steel blades. If a Damascus blade has been hardened with a softer section at the spine or guard, you will get a much better looking etch if you use muriatic acid first, to get the depth you want, and then ferric chloride for adding color.

STELLITE 6-K fits into the same category as Vasco Wear in the wear resistance area, but doesn't need heat treating since there is no iron in it at all. The trick is exceptionally hard particles embedded in a rather soft alloy. Very flexible and easy to bend. Virtually cannot be brought to a mirror finish. Stellite blades are very much in demand by some collectors. The alloy best suited for knives now must be ordered from Canada and costs about a hundred bucks a pound. Part of Stellite's toughness comes from the rolling process used to form the bars. Cast Stellite is not nearly as tough.

is only a marginally acceptable metal for a knife blade. It cannot be hardened much past the mid 40's of the Rockwell C scale, and that's spring, or throwing knife territory. Aside from that, I'm sure that there will soon be collectable titanium knives on many custom makers tables, designed to catch collectors, and not for cutting.

Copyright ©1997 By Blades 'N' Stuff - ALL RIGHTS RESERVED We expect folks to copy and distribute this information without restriction as long as we're listed as the source.


Jump to:Edge Configurations Blade Finishes & Coatings Blade Steels Blade Styles Heat-Treatment

EDGE CONFIGURATIONS - This refers to the cutting edge itself, and we currently offer two primary edge configurations. PLAIN EDGE, which is the traditional straight ground cutting edge. This edge is the most common used in knives due in part to its relative ease of resharpening and overall blade utility. COMBOEDGE™ is the Benchmade term for a blade which is mostly plain edge, but also has a partially serrated edge. This blade enhancement is beneficial to the knife user who has a need for cutting fibrous materials such as rope or webbing on a regular basis. The serration provides a scalpel sharp cutting surface while increasing the cutting edge length in a shorter distance. Benchmade has also created a hook blade in the Rescue Hook models, which is designed to readily cut fibrous materials like a serrated edge, but without the exposed blade edge.

BLADE FINISHES & COATINGS - Blade finishes refers to the surface treatment of the blade, which can be anything from the way in which the steel is processed, to a multitude of blade coatings which are applied to the blade itself. We use a variety of finish methods to "dress" our blades. The two most common terms used to describe Benchmade blade finishes are SATIN, POLISHED, BEAD BLAST, BK1, or BP1.

SATIN FINISH - creates a low-luster sheen to the blade steel surface. Several common forms of satin finish include:

STONEWASH - the blade surface is refined using abrasive tumbling media or "stones" that leave a pronounced random "scratch pattern" on the blade. This finish tends to mask any scratches that may occur with use. Examples- Model 805, 813

SCOTCHBRITE - this finish softly blends the grinding lines on the blade leaving a pleasant "grained" or "brushed" look. Typically the graining pattern goes from spine to edge. Examples- Model 190, 4530
TUMBLED or VIBED- similar to a stonewash finish; this finish leaves the blades bright and smooth with a faint random scratch pattern. Examples- Griptilians, Bali-Songs

BURNISHED - usually applied using non-abrasive media, whether by hand or in vibratory equipment. This finish refines the blade surface without much of a discernable graining or scratch pattern. Examples- Model 770, 941

HAND RUBBED - a finish typically done only by custom knife makers, it is similar to a scotchbrite finish with the main exception being that the graining goes from tang to tip.

POLISHED FINISH - can be defined as any highly-reflective or glossy finish that refines and smoothes the metal surface. This finish aids in corrosion resistance as microscopic peaks and valleys of the blade surface are smoothed out leaving less surface area exposed.

BEAD BLAST FINISH - can be defined as any non-reflective finish applied to the metal surface by bead blasting or sand blasting the blade with any of a variety of media. The intent is to roughen the surface for anti-glare. The trade off is it tends to be more susceptible to corrosion due to the increased surface area exposed. This finish is also commonly referred to as a "military finish".

BK1 BenchKote™ BLADE COATING - Our own proprietary blade coating offering excellent corrosion resistance, which exceeds the ASTM-117 specification for saltwater corrosion resistance. BK1 is a poly-ceramic coating (a blend of polymers and ceramic). It's thinner than the previous blade coating BT2, has equal to or better corrosion resistance (exceeding the ASTM salt spray standard) and unlike BT2 has much better wear resistance due to the ceramic.

BP1 BLADE COATING - BP1 is a physical vapor deposition or 'PVD' process. It offers an extremely hard, thin ceramic surface layer to the blade, and it is applied in a vacuum chamber. Its extreme hardness and excellent adhesion provide wear resistance and lubricity while creating an attractive visual distinction in the process.

BLADE STEELS (Table of Common Steels) When it comes to blade steels, Benchmade not only selects premium grades for their natural qualities, but we also have perfected our own proprietary custom heat treat process which maximizes each steel's edge toughness and cutting performance.

154CM - An American made premium grade stainless steel originally developed for turbine blades in jet engines. The predecessor to ATS-34, which has now seen a strong resurgence in the knife market. Good corrosion resistance with excellent toughness and edge quality.

S30V - An American made and developed premium grade stainless steel created especially for knives. It is a powder made steel with uniform structure and clean steel properties. As a blade it offers excellent corrosion resistance and excellent edge qualities.

D2 - An air-hardened tool steel, which offers good corrosion resistance and excellent mileage in wear resistance. A good choice for hard use environments.

440C - A high-chromium stainless steel with an excellent balance of good hardness and excellent corrosion resistance. 440C takes a nice edge and comes back fairly easy as well. An excellent value priced steel for its performance.

M2 - A very tough, tool grade high-speed steel used primarily as a cutting steel in the industrial area. It offers excellent strength and wear resistance. Due to its make up, it is highly susceptible to corrosion, so we always apply our BT2® coating for corrosion resistance. An excellent choice for hard use environments.

N690 - An Austrian made stainless steel, which is comparable to 440C in performance and value. Keen edge qualities with excellent corrosion resistance.

AUS8 - A high-carbon, low chromium stainless steel, which offers a good balance of toughness, edge sharpness and corrosion resistance. H1- A high-chromium stainless steel, which offers maximum corrosion resistance in both salt water and fresh water-100-percent corrosion resistant. The tradeoff in performance is good edge quality with good edge toughness, so we use it in wet environment rescue or emergency tool applications.

DAMASCUS - A specially forged, layered steel makeup of a variety of steels. It offers excellent toughness and edge quality. For finishing, the surface layers or lines are exposed through an acid etch, which creates a very unique visual effect. Used in special applications due to its inherent high cost and artistic nature.

BLADE STYLES - Tanto- Most tantos seen on the American cutlery market are Americanized formats. Like the Japanese tanto, the Americanized tanto has a high point in-line with the pivot. A flat grind is applied to the point, leaving it very thick and extraordinarily strong. this thick area helps absorb the impact from piercing, as the tanto was originally designed for armor piercing. The front edge meets the bottom edge at an obtuse angle rather than curving to meet it as seen in the Japanese tanto.The only negative aspect of the tanto blade shape is the cutting surface area is sacrificed to gain tip strength.

Drop-Point - A slow convex-curved drop in the point characterizes a drop-point blade. The drop-point format lowers the point for control but adds strength to the tip. Usually coupled with plenty of belly for slicing, this format is often used for hunting knives. It is also a fantastic all-around blade format. This blade shape can be found on a wide array of knives.

Sheepsfoot - This blade shape has no point on the tip, very little to no belly and the spine of the blade curves down to meet the edge. It is used in applications where slicing is the main requirement, and a point is either not needed or would actively get in the way. Emergency rescue blades are usually of this design. The lack of a point prevents the rescuer from inadvertently injuring a victim who is being cut free from something restrictive.

HEAT-TREATMENT - Over the years we have developed a "special recipe" for heat-treating our blade steels. This process maximizes the steels' molecular structure for a custom toughness and Benchmade superior performance. All steels may be created equally, but that is where it stops when it comes to making a Benchmade.

Sunday, August 14, 2005

Knives Continued

Types of knives

Knives exist in several styles:

Fixed Blade Knives

A fixed blade is a knife in which the blade does not fold and extends most of the way into the handle. This type of knife is typically stronger and larger than a folding knife. Activities that require a strong blade, such as hunting or fighting, typically rely on a fixed blade. Some famous fixed blade designs include the
Ka-bar and Bowie knives.

Folding Knives

A folding knife is one that has a pivot between handle and blade, allowing the blade to fold into the handle. Most folding knives are small working blades, pocket knives are usually folding knives.
Some folding knives have a locking mechanism:

The most traditional and commonplace lock is the slip-joint. This isn't really a lock at all, and is found most commonly on traditional pocket knives. It consists of a backspring that wedges itself into a notch on the tang on the back of the blade.

The lockback is the simplest true locking knife. It is found on most traditional locking knives. It is like a slip-joint, but the lock consists of a latch rather than a backspring. To disengage, one presses the latch on the spine of the knife down, releasing the tang.

The linerlock is 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.

The framelock is a variant of the linerlock, however, instead of using the liner, the frame functions as an actual spring. It is usually much more secure than a liner lock.

There are many other modern locks with various degrees of effectiveness. Most of these are particular to single brands, most notably Benchmade's AXIS(tm) lock and SpyderCo's Compression(tm) lock. SOG ARC LOCK is another one that is very good.

Many folding knives (particularly locking models) have a small knob, or thumb-screw that allows the user to open the knife quickly with one hand.

Dorsal vs. Ansall
In the
middle ages, a dorsal meant a knife with a 'back', or a one-sided knife. An ansall was a two-sided knife, with a blade on both sides. These terms have since fallen out of use.

Knife Function

In general, knives are either working (everyday-use blades), or fighting knives. Some knives, such as the Scottish
Dirk and Japanese Tanto function in both roles. Many knives are specific to a particular activity or occupation:

A bread knife is a special knife with a longer, serrated blade especially designed for easily cutting all types of
bread. The blade is straight with a blunt end. The serrations (teeth) allow it to cut bread using less vertical force, so keeping the bread from being compressed. They also leave fewer crumbs than most other knives.

A hunting knife is normally used to dress large game. It is often a normal, mild curve or a curved and clipped blade.
scalpel is a medical knife, used to perform surgery. It is one of the sharpest knives available.

A stockman's knife is a very versatile folding knife with three blades: a clip, a spey and a normal. It is one of the most popular folding knives ever made.

A dive or diver's knife is adapted for underwater use.
Dacor dive knives have tough thermal plastic handles, durable sheaths, and a convenient push-button release, for example.

Utility, or multi-tool knives may contain several blades, as well as other tools such as pliers. Examples include
Leatherman, SOG, Gerber, Wenger and Victorinox (The "Swiss Army knife") tools.

An electrician's knife is specially insulated to decrease the chance of shock.

kukri is a Nepalese fighting and utility knife with a deep forward curve.

Machete blade

machete is a long wide blade, used to chop through brush. This tool (larger than most knives, smaller than a sword) depends more on weight than a razor edge for its cutting power.

A survival knife is a sturdy knife, sometimes with a hollow handle filled with equipment. In the best hollow-handled knives, both blade and handle are cut from a single piece of steel. The end usually has an
O-ring seal to keep water out of the handle. Often a small compass is set in the inside, protected part of the pommel/cap.

The pommel may be adapted to pounding or chipping. Recommended equipment for the handle: a compass (usually in the pommel). Monofilament line (for snares, fishing), 12 feet of black nylon thread and two needles, a couple of plastic ties, two barbed and one unbarbed fishhook (unbarbed doubles as a suture needle), butterfly bandages, halizone tablets, waterproof matches.

Special purpose blades may not be made of metal. Plastic, wood and ceramic knives exist. In most applications, these relatively fragile knives are used to avoid easy detection.

Custom-made knives called
microtomes are used to cut specimens for microscopy. The sharpest knives ever constructed are probably the ultramicrotomes with diamond edges used to slice samples for electron microscopes.

boning knife is used for deboning meat, poultry, and fish.
For whittling (artistic wood carving) a blade as short as 25mm (1 inch) is common.

Serrations on a blade "saw" through the item being cut and stay sharp for a long time. The points protect the slicing areas from nicks. A good serration pattern will stay sharp several times as long as a straight edge.

The edge is sharpened at different angles for different purposes. 15 to 25 degrees is a good all-around angle. Slicing knives should have sharper angles, down to ten degrees. Chopping knives need blunter angles, out to thirty degrees.

Using knives

A sharp knife is a safe knife. Dull knives lead to excessive use of force to cut materials, increasing the chance that the blade may slip and the force will be transferred to an unintended destination such as yourself or another person or object.

Boy Scout parlance, an area within the radius of the arm and blade length combined is called the 'blood circle'. Also, a dull or damaged knife will inflict a worse wound than a relatively 'clean' cut from a sharp knife.

Knives proffered to another person should always be offered handle first.

A knife should be kept clean, dry and sharp. Steel blades
rust easily, but oiling will prevent pitting due to oxidation and tarnish. Most knives are not intended as pry bars or screwdrivers.

Either use is likely to break off the tip of the blade, or to bend or break the knife beyond repair. Most high quality knives are also tempered very hard, so that they will retain an edge longer. However, this also makes them brittle.


Knives are sharpened by grinding against a hard surface, typically stone. The smaller the angle between the blade and stone, the sharper the knife will be, but the faster it will dull. A guide is very helpful. Very sharp knives sharpen at 12-15 degrees.

Typical knives sharpen at 22 degrees. Knives that chop may sharpen at 25 degrees. In short, the harder the material to be cut the higher the angle of the edge. The composition of the stone affects the sharpness of the blade (finer grain produces sharper blades), as does the composition of the blade (some metals take/keep an edge better than others).

Examples of sharpening tools are the clamp-style systems, which use a clamp with several holes with pre-defined angles. The stone is mounted on a rod and is pulled through these holes, so that the angle remains consistent.

Another variant is the crock stick setup, where two sticks are put into a plastic or wooden base to form a V shape. When you pull a knife up the V, the angle is held for you, as long as you hold the blade perpendicular to the base.

Remove a wire edge (burr) if one forms during sharpening. Use a slighly steeper angle with very light pressure to do so. If not removed, it will break off in use, and the knife will instantly become dull. An alternate method of removing a wire edge is stroking from side to side on a very fine stone, using light strokes. This will flip the burr back and forth as it is ground off.

To feel for a wire edge, move your thumb lightly across the edge. It should come off with no resistance. If you feel a little bit of pull at the edge or the nail is sightly abraded, you may have a wire burr.

Honing stones (also called
whetstones) come with coarse and fine grits and can be hard or soft describing whether the grit comes free.

Arkansas is a traditional source for honing stones, which are traditionally (though a poor practice) used with water or honing oil.

India is another traditional source for stones.

Ceramic hones are also common, especially for fine grit size.
Water stones (both artificial and natural) come in very fine grits. They are stored in water, and develop a layer of slurry which dulls the edge if you hone the blade as if honing into the stone. Generally, these are more costly than oilstones. Oil is not to be used on these.

Oil is sometimes used to lift the metal dust, called swarf, off the stone. This is generally bad to do during polishing. There are better ways than oil to clean a hone.

Coated hones, which have an abrasive, sometimes diamonds, on a base of plastic or metal are another kind of hone. Rather expensive, are sharpening blocks made with

Stropping a knife is sometimes a finishing step. This is traditionally done with a leather strap impregnated with abrasive compounds, but can be done on paper, cardstock, or even cloth in a pinch. It will not cut the edge significantly, but produces a very sharp edge with very little metal loss. It is useful when a knife is still sharp, but has lost that 'scary sharp' edge from use.

Other times the final step is done with a steel. This fine process can effect alignment of the edge. Realigning the edge goes a long way in keeping the knife sharp, as often times, a rolled edge will make an otherwise sharp knife dull.

Mechanical Consideration of Rolled Edges

If a knife is used as a scraper or encounters hard particles in softer materials or is used asymmetrically, there may be a sideways load near the tip. In this case the knife should resist bending or breaking.

Making some simplifying assumptions about the forces and the knife edge's ability to resist them may shed some light on ideal sharpening. Assume the knife is thin and the force is applied at the very edge.

Sheets of material are bent by stretching the outside or compressing the inside. Both the area taking the force and the lever arm converting force to torque are proportional to thickness, so the bending resistance is proportional to the square of the thickness. (That explains the strength per weight of aluminum, compared to steel.)

If the force is applied at the edge, the bending torque is proportional to the distance from the edge. So, in this case, the ideal cross section is proportional to the square root of the distance from the edge. This is a (microscopic) parabola. This contrasts to the usual practice of trying to sharpen knives to a wedge near the edge.

Perhaps this sheds light on the function of razor straps and on the practice of using two angle guides to sharpen a knife.
On the other hand if the type of use cannot be predicted, it may be better to sharpen it to a wedge and let the first use bend the edge to an appropriate curve.

A wedge shape has the property called "scale invariance". It has the same relative shape for any depth of cut.

Legal considerations

Even small knives are forbidden on all commercial airliners and are among the illegal imports that may be confiscated at airports by customs staff even if packed in luggage.

The knife laws of different countries vary, but are generally strict in Western countries.

Knife laws in U.S. cities vary tremendously. In
Texas, for example, individuals may carry knives openly or concealed so long as they are single-edged, and are not daggers, switchblades, or gravity knives (balisong legality is questionable — there have been convictions). In some other States, fixed-blade knives are banned, open carry is banned, and sometimes concealed carry of anything except pocketknives is banned.

Cities have ordinances further restricting these laws; in San Antonio, TX, it is a violation to carry a folding knife having a locking blade. In some metro areas such as Washington, D.C., going into office buildings or museums, or simply loitering, carrying even small 3" folding knives can be problematic.

Other restricted areas in the U.S. include court buildings and federal property (the latter of which technically has a limit of 2.5inches for blades).

Carrying knives in public is generally forbidden by law in many countries. Exceptions may be made for hunting knives, and for knives used for work-related purposes (e.g. chef's knives).

Automatic knives (
switchblades) are almost universally banned from civilian carry if not possession. Balisongs (butterfly knives) are only slightly less stigmatized, and tend to be treated as switchblades by unfriendly law enforcement agencies.

Most Western European nations are very unfriendly toward all knives other than small pocket knives and similarly small tools, which are nonetheless not allowed on planes or in certain other venues.

Even multitools like the
SwissTool, Gerber multitools, and Leatherman multitools are often frowned upon, due to their having relatively large blades and/or locking ability.

Knife modifications

Knives can be sometimes be customised to the user and/or application:
The handle can be altered in shape (for better grip) or material (to prevent electrical shock or burns).

The surface finish of the blade can be darkened or polished.

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