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Knife

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A knife is a specialized tool or weapon defined by having a cutting edge or blade.

Knife parts
Knife parts

This tool is one of the earliest instruments used by humanity. Evidence of its existence dates back at least 2.5 million years.

Stone Knife, Nok Museum
Stone Knife, Nok Museum

Early versions were crafted from organic or natural materials like wood, bone, and stone. Materials such as flint and obsidian were common in these ancient times. As metallurgy and manufacturing improved, the materials used for blades changed significantly. Humans began using copper, bronze, iron, and steel to create more durable edges. Today, advanced materials like ceramic and titanium are also used in modern knife production.

A modern knife is composed of several distinct parts that work together.

Knife parts
Knife parts

The blade is the primary component and contains the cutting surface. This surface extends from the point, which is used for piercing, to the heel. The thickest part of the blade is called the spine. On single-edged knives, the spine is the side opposite the edge. Some blades feature a fuller, which is an optional groove used to make the blade lighter. The ricasso is a flat section of the blade located near the junction of the blade and the handle. To prevent a user's hand from slipping onto the edge, many knives include a bolster or guard. The handle is the part used to grip and manipulate the blade safely. At the very end of the handle is the hilt or butt, which can be used for blunt force.

Knives are categorized by their mechanical construction, primarily as fixed-blade or folding knives.

Fixed Blade Full Tang Survival Knife
Fixed Blade Full Tang Survival Knife

A fixed-blade knife, sometimes called a sheath knife, does not fold or slide. These are often stronger because they lack moving parts. Many fixed-blade knives utilize a full tang. A tang is a portion of the blade that extends into the handle. A full tang reaches the entire length of the handle, providing significant strength. In contrast, a folding knife connects the blade to the handle through a pivot. This allows the blade to fold into the handle for safer storage.

Swiss army knife open 20050612 (cropped)
Swiss army knife open 20050612 (cropped)

To prevent injury, folding knives usually include a locking mechanism to keep the blade open during use.

There are many different locking mechanisms used in folding knives to ensure safety.

Folding knife locking mechanisms
Folding knife locking mechanisms

A slip joint is common in traditional pocket knives and uses a spring to hold the blade. A lockback, or spine lock, uses a pivoted latch that must be pressed to release the blade. The linerlock, invented by Michael Walker, uses a side-spring lock that can be operated with one hand. Another variation is the frame lock, which was updated by custom maker Chris Reeve for the Sebenza. More complex systems include the compression lock and the axis lock, which uses a cylindrical bearing. Some automatic knives use a button lock to release the blade via a spring. These mechanisms allow for different levels of strength, legality, and ease of use.

The manufacturing of a blade involves specific metallurgical processes to ensure performance.

Chinese knife factory
Chinese knife factory

Makers typically use either forging or stock removal. Forging involves heating a single piece of steel and shaping it while hot with a hammer or press. Stock removal involves grinding away metal to achieve the desired shape. After shaping, the steel must undergo heat treatment to change its properties. This process requires heating the steel above its critical point and then quenching it to harden the metal. Finally, the blade is tempered to remove internal stresses and increase toughness.

Material choice is critical because different alloys offer different advantages.

Morakniv Basic 511 Carbon Steel 5
Morakniv Basic 511 Carbon Steel 5

Carbon steel is an alloy of iron and carbon that can be extremely sharp. While it holds an edge well, it is vulnerable to rust and stains. Stainless steel, an alloy containing chromium, is highly resistant to corrosion but may not hold as sharp an edge. High carbon stainless steel attempts to combine the benefits of both materials.

Damascus Bowie
Damascus Bowie

Laminated blades use multiple layers of metal to balance toughness and corrosion resistance. Damascus steel is a specific form of pattern welding where different steel types are welded together to create visible patterns. Other materials include titanium, which has a high strength-to-weight ratio, and ceramic, which is hard and lightweight but very brittle.

Knives serve a massive variety of specialized roles across human culture.

Old Swiss table knives
Old Swiss table knives

Hunters use hunting knives, while soldiers rely on combat knives. Kitchens utilize many specific types, such as the chef's knife, paring knife, bread knife, and cleaver. Table knives include butter and steak knives for dining. Some knives are designed for specialized tasks, like throwing or juggling. Others hold deep cultural significance, such as the kirpan used in religious ceremonies. Because of their versatility, knives remain essential tools in almost every human activity, from food preparation to survival.

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🖼️ Images & Media (25)
File:Damascus Bowie.jpg
Damascus Bowie.jpg
File:Knife parts.jpg
Knife parts.jpg
File:Fixed Blade Full Tang Survival Knife.png
Fixed Blade Full Tang Survival Knife.png
File:Morakniv Basic 511 Carbon Steel 5.jpg
Morakniv Basic 511 Carbon Steel 5.jpg
File:Chinese knife factory.jpg
Chinese knife factory.jpg
File:Microtome-knife-profile.svg
Microtome-knife-profile.svg
File:CKc Pen Knife.jpg
CKc Pen Knife.jpg
File:Swiss army knife open 20050612 (cropped).jpg
Swiss army knife open 20050612 (cropped).jpg
File:BM-AxisLock.jpg
BM-AxisLock.jpg
File:Folding knife locking mechanisms.svg
Folding knife locking mechanisms.svg
File:OTF knife GM08.jpg
OTF knife GM08.jpg
File:Складной нож Минск цена 85 коп 1980-е годы ф5.JPG
Складной нож Минск цена 85 коп 1980-е годы ф5.JPG

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