Knife

A knife is a sharp object used for cutting things, based on the simple machine concept of a wedge. The most common design for a knife is that of a sharp metal blade attached to a handle by means of a tang. Knives have been used as weapons and tools since the stone age, and various developments include the sword and the machete.

Knives were among the first tools used by man in the Stone age, originally consisting of a single piece of sharpened flint.

Anatomy of a Knife

A knife has a blade, a tang and a handle. The tang is an extension of the blade into the handle, so that the handle can be strongly attached to the blade.

Every sculptured curve of a knife blade or handle has a name and purpose.

First, there are several basically different types of knife blades: normal, spey, clipped, sheeps-foot and ulu.

A normal blade has a curving edge, and flat back. Most kitchen knives are normal blades. A dull back lets one use fingers to concentrate force, and makes the knife heavier and stronger for its size. The curve concentrates force, making cutting easier. Therefore, it can chop as well as pick and slice. Traditionally the curve helped skin and scrape the skin of small animals. The point helps one to cut cones and pick at small objects. The single edge is also less expensive to produce than a double edge.

A spey blade has two curved edges. The idea is to make a blade that slices in either direction, and whose point is strong and sharp. This allows the knife to be moved within an opponent's body to create damage. Daggers, switchblades and fighting knives are spey. Traditional daggers strengthened the point. The modern "scientific" style uses bigger curves to concentrate forces for slicing (rather than a straight edge as in old-fashioned daggers).

A clipped blade is like a normal blade with a clip off the tip to make the tip thinner and sharper. Sometimes the back edge of the clip has a "cut swedge" that can be sharpened to make a fighting knife. The clip is the classic shape for a pocket knife. The sharp tip makes the blade exceptional as a pick, or for cutting in tight places (like food, or opening packages). This is the preferred shape when a knife is the only eating utensil, because it skewers food best. It's also the best knife for cutting skin while dressing an animal.

A sheepsfoot knife has a straight edge, and a curved dull back. It give the most control, because the back, dull edge is made to be held by fingers. It was used to trim sheep's hooves. It's also used for whittling.

An ulu knife is a sharpened half-circle. It's all edge, with no point, and a handle in the middle. It's good for scraping, and sometimes chopping. It is the strongest knife-shape.

Knives designed for specific purposes exist in large numbers. Some examples include butchering, hunting, curing, fishing, woodcarving, cooking and combat.