Knife
From Wikipedia, the free encyclopedia
A knife is a sharp-edged (single or double edged) instrument consisting of a thin blade used for cutting and fitted with a handle. The knife can be used as a tool or a weapon. Considered by some to be one of the most useful tools of all time, its origins date as far back as two-and-a-half million years ago, as evidenced by the Olduwan tools.[1][2]
Contents
|
[edit] History
The earliest knives were shaped by percussion flaking from rock, particularly water-worn creek cobbles made out of volcanic rock. During the Paleolithic era Homo habilis likely made similar tools out of wood, bone, and similar highly perishable material that has not survived.[2][3] As recent as five thousand years ago, as advances in metallurgy progressed, stone, wood, and bone blades were gradually succeeded by copper, bronze, iron, and eventually steel. Modern knives may be made from many different materials such as carbon fiber, ceramics, and titanium.
Knives gained prominence during the Middle Ages as one of the three major items of cutlery in the western world, accompanying the fork and spoon, and in this way much of the world's population is exposed to knives on a daily basis.
There is a very active community of modern custom knife makers and collectors. The American Bladesmith Society promotes forged blades; the Knifemakers Guild promotes all custom knives.
[edit] Materials and construction
Today, knives come in many forms but can be categorized between two different types: fixed blade knives and folding, or pocket, knives. Although each has inherent advantages, the two have many similar characteristics.
Modern knives consist of a blade (1) and handle (2). The blade can be fine or serrated. The handle, used to grip and manipulate the blade safely, may include the tang, a portion of the blade that extends into the handle. The blade consists of the point (3), the end of the knife used for piercing, the edge (4), the cutting surface of the knife extending from the point to the heel, the grind (5), the cross-section shape of the blade, the spine, (6), the top, thicker portion of the blade, the fuller (7), the groove added to lighten the blade, and the bolster (8), the thick portion of the blade joining the blade and the handle. The guard (9) is a barrier between the blade and the handle which protects the hand from an opponent, or the blade of the knife itself. A choil, where the blade is unsharpened and possibly indented as it meets the handle, may be used to prevent scratches to the handle when sharpening or as a forward-finger grip. The end of the handle, or butt (10), may allow a lanyard (11), used to secure the knife to the wrist.[4][5]
[edit] Blade
Knife blades can be manufactured from a variety of materials, each of which has advantages and disadvantages. Carbon steel, an alloy of iron and carbon, can be very sharp, hold its edge well, and remain easy to sharpen, but is vulnerable to rust and stains. Stainless steel is an alloy of iron, chromium, possibly nickel, and molybdenum, with only a small amount of carbon. It is not able to take quite as sharp an edge as carbon steel, but is highly resistant to corrosion. High carbon stainless steel is stainless steel with a higher amount of carbon, intended to combine the best attributes of carbon steel and stainless steel. High carbon stainless steel blades do not discolor or stain, and maintain a sharp edge. Laminate blades use multiple metals to create a layered sandwich, combining the attributes of both. For example, a harder, more brittle steel may be sandwiched between an outer layer of softer, tougher, stainless steel to reduce vulnerability to corrosion. In this case, however, the part most affected by corrosion, the edge, is still vulnerable. Pattern-welding is similar to laminate construction. Layers of different steel types are welded together, but then the stock is manipulated to create patterns in the steel. Titanium is metal that is lighter, more wear resistant, and more flexible than steel. Although less hard and unable to take as sharp an edge, carbides in the titanium alloy allow them to be heat-treated to a sufficient hardness. Ceramic blades are incredibly hard, lightweight blades; so hard that they will maintain a sharp edge for months or years with no maintenance at all. They are immune to corrosion, but can only be sharpened on silicon carbide sandpaper and some grinding wheels. Plastic blades are not very sharp at all but are typically serrated, and are usually considered disposable.[6]
Steel blades are commonly shaped by forging or stock removal. Forged blades are made by heating a single piece of steel, then shaping the metal while hot using a hammer or press. Stock removal blades are shaped by grinding and removing metal. With both methods, after shaping, the steel must be heat treated. This involves heating the steel above its critical point, then quenching the blade to harden it. After hardening, the blade is tempered to remove stresses and make the blade tougher. With common kitchen cutlery, forged blades are often seen in more expensive knives. Forged blades can often be distinguished from stock removal blades by the presence of an integral bolster.
The edge of the knife can be sharpened to a cutting surface in a number of different ways. Flat ground blades have a profile that tapers from the thick spine to the sharp edge in a straight or convex line. Seen in cross section, the blade would form a long, thin triangle, or where the taper does not extend to the back of the blade, a long thin rectangle with one peaked side. Hollow ground blades have concave, beveled edges that are ground starting midway down the blade, instead of at the spine. The resulting blade has a thinner edge, so it may have better cutting ability, but it is lighter and less durable than flat ground blades. Serrated blade knives have a wavy, scalloped or saw-like blade. Serrations make knives ideal for cutting things that are hard on the outside and soft on the inside that might otherwise be damaged by a knife with a plain edge blade. Serrated knives cut much better than plain edge blade knives when dull, so they may last longer without sharpening, and require a special tool to be sharpened.
[edit] Fixed blade features
A fixed blade knife does not fold or slide, and is typically stronger due to the tang, the extension of the blade into the handle, and lack of movable parts.[6]
[edit] Folding blade features
A folding knife can pivot, allowing the blade to fold into the handle. Although not likely to have a guard or full tang, folding knives typically have a locking mechanism. One common mechanism, found traditionally on pocket knives, is the slip joint. Once opened, the blade does not lock, but is held in place by a spring device that allows the blade to fold if a certain amount of pressure is applied. Alternately, the lockback can be used. Like the slip-joint the lockback includes a pivoted latch connected to a spring, and can be disengaged only by pressing the latch down to release the blade.[6]
Another feature associated with the folding knife is a small knob, disk or hole that allows the user to open the knife with one hand, leaving the other hand free.
[edit] Sliding blade features
A sliding knife is a knife which can be opened by sliding the knife blade out the front of the handle. One method of opening is where the blade exits out the front of the handle point-first and then is locked into place (an example of the this is the gravity knife). Another form is a O-T-F (out-the-front) switchblade, which only requires the push of a button or spring, the knife is "slid" out of the handle, and locked into place. To retract the blade back into the handle, a release lever or button, or linerlock is pressed.
[edit] Handle
The handles of knives can be made from a number of different materials, each of which has advantages and disadvantages. Wood handles provide good grip, but are more difficult to care for. They do not resist water well, and will crack or warp with prolonged exposure to water. Plastic handles are more easily cared for than wooden handle, but can be slippery and become brittle over time. Lighter than other materials, this may result in a knife that is unbalanced or too light. Stainless steel handles are durable and sanitary, but can be slippery. To counter this, many premium knife makers make handles with ridges, bumps, or indentations to provide extra grip.
[edit] Types of knives
- For more details on the various types of knives, see Blade#Patterns of knife blades.
[edit] Knives as weapons
As a weapon, the knife is universally adopted as an essential tool. For example:
- Knife bayonet: A knife-shaped close-quarter fighting weapon designed to fit on or over the muzzle of a rifle barrel or similar weapon, used as a last-resort weapon or tool
- Combat knife: Any knife intended to be used mainly in close-quarter fighting
- Trench knife: Purpose-made or improvised knives, intended for close-quarter fighting, particularly in trench warfare
[edit] Knives as utensils
A primary aspect of the knife as a tool includes dining, used either in food preparation or as cutlery. Examples of this include:
- Bread knife: A knife with a serrated blade for cutting bread
- Boning knife: A knife used for removing the bones of poultry, meat, and fish
- Carving knife: A knife for carving large cooked meats such as poultry, roasts, hams
- Chef's knife: Also known as a French knife, a cutting tool used in preparing food
- Electric knife: An electrical device consisting of two serrated blades that are clipped together, providing a sawing action when powered on
- Kitchen knife: Any knife, including the chef's knife, that is intended to be used in food preparation
- Table knife: A piece of cutlery, either a butter knife, steak knife, or both, that is part of a table setting, accompanying the fork and spoon
[edit] Knives as tools
As a utility tool the knife can take many forms, including:[6]
- Bowie knife: Commonly, any large sheath knife, or a specific style of knife designed by Colonel Jim Bowie
- Butterfly knife: A folding knife also known as a balisong, with two handles counter-rotating around the tang such that, when closed, the blade is concealed within the handles
- Diver's knife: A knife adapted for use in diving and watersports and a necessary part of standard diving dress
- Electrician's knife: An insulated knife used to cut electrical wire
- Hunting knife: A knife used to dress large game
- Pocket knife: Also known as a multi-tool or jackknife, a knife which may contain several blades, as well as other tools
- Palette knife: A knife, or frosting spatula, lacking a cutting edge, used by artists for tasks such as mixing and applying paint, and in cooking for spreading icing
- Scalpel: A medical knife, used to perform surgery
- Straight razor: A reusable knife blade used for shaving hair
- Survival knife: A sturdy knife, sometimes with a hollow handle filled with survival equipment
- Switchblade: A knife with a folding blade that springs out of the grip when a button or lever on the grip is pressed
- Utility knife: A knife used for cutting sheet materials, including cardboard boxes
[edit] Knives as a tradition
- Kukri: A Nepalese knife used as both tool and weapon
- Laguiole knife: A traditional French pocket-knife, originally produced in the town of Laguiole in the Aveyron region of southern France in the early 19th century
- Lajinaa: A small spear, sometimes used in close range battles, used mostly by Spaniard pirates who raided trade ships in the gulf coast
- Mora knife: Similar in design to Finnish puukkos, a range of belt-knives manufactured by the cutleries of the town of Mora in Dalarna, Sweden
- Opinel knife: A simple, inexpensive, wooden pocket-knife, manufactured since the 1890s in the town of Saint-Jean-de-Maurienne in the Savoie region of France
- Puukko: A traditional Finnish or Scandinavian style woodcraft belt-knife used as a tool rather than a weapon
- Sabatier: A cooking knife manufactured in Thiers, France from well established manufacturers from the early 19th century
- Seax: A Germanic single-edged knife, used primarily as a tool, but may also have been a weapon
- Ulu: An Inuit woman's all-purpose knife
[edit] Rituals and superstitions
- See also: Ritual and Superstition
The knife plays a significant role in some cultures through ritual and superstition. As the knife was an essential tool for survival since early man[2], it can be found from the cradle—a knife placed under the bed while giving birth is said to ease the pain, or stuck into the headboard of a cradle to protect the baby[7][8]—to grave—so the dead would not be defenseless in the next world.[9][10][11] As such, the knife plays an important role in some initiation rites, and many cultures perform rituals with a variety of knives, including the ceremonial sacrifices of animals.[12] Samurai warriors, as part of bushido, could perform ritual suicide, or seppuku, with a tantō, a common Japanese knife.[13] An athame, a ceremonial black-handled knife, is used in Wicca and other forms of modern witchcraft.[14][15]
In Greece a black-handled knife placed under the pillow is used to keep away nightmares.[16] As early as 1646 reference is made to a superstition of laying a knife across another piece of cutlery.[17] A common belief is that if a knife is given as a gift, the relationship of the giver and recipient will be severed. Something such as a small coin is exchanged for the gift, rendering "payment."[8]
[edit] Legislation
Knives are typically restricted by law, although restrictions vary greatly by country or state and type of knife. For example, some laws restrict carrying an unconcealed knife in public while other laws can restrict even private ownership of certain knives, such as switchblades.
[edit] Further reading
- Everybody's Knife Bible by Don Paul, ISBN 0-938263-23-4