A knife is a handheld sharp-edged instrument consisting of handle attached to a blade used for cutting. The knife is a tool that can be used as a weapon. Its origins date as far back as two-and-a-half million years ago, as evidenced by the Oldowan tools.

History

image:The knife Grinder - 1853.jpg

The earliest knives were shaped by knapping (percussive flaking) of rock, particularly harder rocks such as obsidian and flint. During the Paleolithic era Homo habilis likely made similar tools out of wood, bone, and similar highly perishable materials that have not survived. 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. The first metal (copper) knives were symmetrical double edged daggers, which copied the earlier flint daggers. In Europe the first single edged knives appeared during the middle bronze age. These replaced daggers, which by that time had evolved into swords. Modern knives may be made from many different materials such as alloy tool steels, carbon fiber, ceramics, and titanium.There is a very active community of modern custom knife makers and collectors, who often pioneer the use of new materials in knives. In the United States, The American Bladesmith Society promotes forged blades; the Knifemakers Guild promotes all custom knives.

Materials and construction

main: Knife making Today, knives come in many forms but can be generally categorized between two broad types: fixed blade knives and folding, or pocket, knives.

image:Knife parts.jpg Modern knives consist of a blade (1) and handle (2). The blade edge can be plain or serrated or a combination of both. The handle, used to grip and manipulate the blade safely, may include the tang, a portion of the blade that extends into the handle. Knives are made with partial (extending part way into the handle) and full (extending the full length of the handle, often visible on top and bottom) tangs. The handle can also include a bolster, which is a piece of material used to balance the knife, usually brass or other metal, at the front of the handle where it meets the blade. 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 ricasso (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, or a portion of the tang to protrude as a striking surface for pounding or glass breaking.