Pocketknife

A pocketknife is a knife with one or more blades that fold into the handle. It is also known as a jackknife, or a folding knife. It may be referred to as a penknife, though a penknife may also be a specific kind of pocketknife. A typical blade length is.
Pocketknives are versatile tools, and may be used for anything from whittling and woodcarving, to butchering small game, gutting and filleting small fish, aiding in the preparation of tinder and kindling for fires, boring holes in soft material, to opening an envelope, cutting twine, slicing fruits and vegetables or as a means of self-defense.
Pocketknives may also be used in conjunction with other tools and equipment for woodcraft and bushcraft.
Specialised designs are also used for mushroom hunting and gardening. Pocketknives designed for gardening include pruning knives, which are folding knives with long curved blades used for pruning, trimming cuttings, taking buds and preparing material for grafting.

History

The earliest known pocketknives date to at least the early Iron Age. A pocketknife with a bone handle was found at the Hallstatt Culture type site in Austria, dating to around 600–500 BCE. Iberian folding-blade knives made by indigenous artisans and craftsmen and dating to the pre-Roman era have been found in Spain. Many folding knives from the Viking Age have been found. They carried some friction binders, but more often they seem to have used folding knives that used a closure to keep the blade open.

Peasant knife

The peasant knife, farmer knife, or penny knife is the original and most basic design of a folding pocketknife, using a simple pivoted blade that folds in and out of the handle freely, without a backspring, slipjoint, or blade locking mechanism. The first peasant knives date to the pre-Roman era, but were not widely distributed nor affordable by most people until the advent of limited production of such knives in cutlery centers such as Sheffield, England commencing around 1650, with large-scale production starting around the year 1700 with models such as Fuller's Penny Knife and the Wharncliffe Knife. Some peasant knives used a bolster or tensioning screw at the blade to apply friction to the blade tang in order to keep the blade in the open position. The smallest Opinel knives are an example of the peasant knife. The knife's low cost made it a favorite of small farmers, herdsmen, and gardeners in Europe and the Americas during the late 19th and early 20th century.

Slip joint knife

Most pocketknives for light duty are slipjoints. This means that the blade does not lock but, once opened, is held in place by tension from a flat bar or leaf-type backspring that allows the blade to fold if a certain amount of pressure is applied. The first spring-back knives were developed around 1660 in England, but were not widely available until the Industrial Revolution and development of machinery capable of mass production. Many locking knives have only one blade that is as large as can be fitted into the handle, because the locking mechanism relies on a spring-loaded latch built into the spine or frame of the handle to lock it and it is difficult to build in multiple levers, one for each blade. Slipjoints tend to be smaller than other typical pocketknives.
Some popular patterns of slipjoint knives include:

Pattern	Description	Image
Barlow	The Barlow knife has a characteristically long bolster, an elongated oval handle, and one or two blades. It is assumed to have been named after its inventor, although there is some dispute as to which Barlow this actually was. First produced in Sheffield, England, the Barlow knife became popular in America in beginning of the nineteenth century.
Camper or Scout	The traditional camper or scout knife has four tools: a large drop point blade along with a can opener, combination cap lifter/slotted screwdriver, and an awl or punch. Many other combinations of large and small drop point blades, a Phillips-head screwdriver, saw, etc. are also considered camper/scout knives.
Canoe	The canoe knife is shaped somewhat like a native American canoe and typically has two drop-point blades.
Congress	The congress knife has a convex front with a straight or shallow concave back. It usually carries four blades.
Cotton Sampler	Longish handle compared to single shorter blade. Blade is scalpel shaped with a belly. Bolster on blade end only. Lanyard hole makes hand carrying easier for frequent field use.
Dog Bone	Double bolstered handle with a blade opening from each end. The blade is symmetrical, with roughly parallel sides.
Dog Leg	A double bolstered handle with a significant cant, resembling the shape of a dog's hind leg. Can have one or two blades that open from the same end.
Elephant's toenail	The elephant's toenail is a large design similar to the sunfish but usually tapers on one end giving it the "elephant's toenail" shape. These knives, like the sunfish, usually have two wide blades.
Hawkbill	Technically a blade type, but also a traditional single-bladed slip joint knife with a single bolster on the blade end, and a teardrop-shaped handle.
Lady Leg	Drop point blade paired with a clip point blade, with a handle shaped like a lower leg with a high-heeled shoe, which forms a functional bottle opener.
Marlinspike	A single sheepsfoot or hawkbill blade, with a large marlinspike, to assist in untangling knots or unravelling rope for splicing on the opposing side.
Melon Tester	Single long and narrow drop point blade, used for taking a sample from watermelon.
Muskrat	Two narrow clip point blades, one from each end, with double bolsters.
Peanut	A smaller knife with a clip point and drop point from the same end, double bolsters on a slightly wavy handle.
Penknife	The penknife was originally intended to sharpen quill pens, but continues to be used because of its suitability for fine or delicate work. A penknife generally has one or two pen blades, and does not interfere with the appearance of dress clothes when carried in the pocket.
Sodbuster	The sodbuster or Hippekniep or Notschlachtmesser has a simple handle with no bolster and only one blade. It is an economic design, usually with wood or celluloid scales, lacking metal bolsters.
Sow Belly	Has a handle with deeply bowed "belly", similar to a stockman, but more pronounced. It may have a single clip point blade, or a sheepsfoot and clip point blade opposite a shorter spey blade.
Stockman	The stockman has a clip, a sheep's foot and a spey blade. They are usually middle-sized. There are straight handled and sowbelly versions.
Sunfish	The sunfish is a large design with a straight handle and two bolsters. The blades are usually short, but both the handle and blades are very wide. Sunfish knives usually have two blades.
Toothpick	Elongated knife, with a single narrow clip point blade. Handle has bolsters at both ends, and is turned up or tapered on the opposite end of the blade. Variations include oversized versions called Arkansas or Texas Toothpicks, and miniaturized version, called a Baby Toothpick.
Trapper	The trapper is larger knife with a clip and a spey blade. The blades are usually hinged at the same end.
Whittler	The whittler is a type of pen knife with three blades, the master blade bearing on two springs.

Multi-tool knives

knives formerly consisted of variations on the American camper style or the Swiss Army knives manufactured by Victorinox and Wenger. However, the concept of a multitool knife has undergone a revolution thanks in part to an avalanche of new styles, sizes, and tool presentation concepts. These new varieties often incorporate a pair of pliers and other tools in conjunction with one or more knife blade styles, either locking or nonlocking.
Multitool knives often have more than one blade, including an assortment of knife blade edges as well as a selection of other tools such as bottle openers, corkscrews, and scissors. A large tool selection is the signature of the Swiss Army Knife. These knives are produced by Victorinox and Wenger and issued to military services and sold to the public. Similar to the Swiss Army knife is the German Army knife, with two blades opening from each side and featuring hard plastic grips and aluminum liners. The U.S. Military utility knife, issued by the United States Army, Navy, and Marine Corps, was made for many years by the Camillus Cutlery Company and Imperial Schrade as well as many other companies. It was originally produced with carbon steel blades and brass liners, but with the onset of the Vietnam War was modified to incorporate all-stainless steel construction. The current-issue U.S. military utility knife has textured stainless grips and four stainless blades/tools opening on both sides in the camper or scout pattern and has an extremely large clevis or bail. The Victorinox Swiss Army Soldier Knife has been issued a National Stock Number to be authorized for issue to US service members. This is the first time a US military issued utility/pocket knife that was not manufactured in the United States has been adopted.