Originally made of rock, bone, flint and obsidian, knives have evolved in construction as technology has, with blades being made from bronze, copper, iron, steel, ceramics and titanium. Most modern-day knives follow either a fixed-blade or a folding construction style, with blade patterns and styles as varied as their makers:
Fixed: A fixed blade knife (like these SOG Knives), sometimes called a sheath 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 moving parts.
Folding: A folding knife connects the blade to the handle through a pivot, allowing the blade to fold into the handle. To prevent injury folding knives typically have a locking mechanism.
The blade edge can be straight or serrated, or a combination of both. A serrated blade has a cutting edge that has many small points of contact with the material being cut. Cuts made with a serrated blade are typically less smooth and precise than cuts made with a smooth or straight edge blade. A serrated blade has a faster cut, but a straight edge blade has a cleaner cut.
A blade consists of:
Point: The end of the knife used for piercing.
Edge: The cutting surface of the knife extending from the point to the heel.
Spine: The thickest section of the blade.
Fuller: The groove added to lighten the blade.
Ricasso: The flat section of the blade located at the junction of the blade and the knife’s bolster or guard.
Guard: The barrier between the blade and the handle.
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 tangs (extending part way into the handle) or full tangs (extending the full length of the handle, often visible on top and bottom).
The handle of knives can be made from a number of different materials, and are produced in a wide variety of shapes and styles:
Wood: Provides good grip and are warm in the hand. Modern stabilized and laminated wood handles are usually water resistant.
Injection molded: Made from higher grade plastics, they are trademarked under names such as Zytel™ or Grivory™, and are reinforced with Kevlar™ or fiberglass.
Rubber: Kraton® or Resiprene-C materials are generally durable and cushioning.
Leather: Used on some hunting and military knives.
Skeleton: Refer to the practice of using the tang itself as the handle, usually with section of material removed to reduce weight. They are often wrapped to enhance grip.
Stainless steel/aluminum: Durable and sanitary, these handles are often made with ridges or bumps to enhance grip.
Types of Knives and Tools
Throwing Knife: A knife designed and weighted for throwing.
Boning Knife: A knife used for removing the bones of poultry, meat and fish.
Bowie Knife: Commonly, any large sheath knife, or a specific style of large knife.
Hunting Knife: A knife used to dress large game.
Machete: A large, heavy knife used to cut through thick vegetation.
Survival Knife: A sturdy knife, sometimes with a hollow handle filled with survival equipment.
Utility Knife: A short knife with a replaceable triangle blade.
Tactical Knife: Any knife intended to be used by soldiers in the field, as a general-use tool.
Pocket Knife: A folding knife designed to be carried in a pants pocket.
Lockback Knife: A folding knife with a mechanism that locks the blade into the open position.
Multi-Tool: Combines a folding knife with other tools and implements, such as pliers, scissors, screwdrivers and more.
Slip Joint: Found most commonly on traditional pocket knives. The opened blade does not lock, but is held in place by a spring device that allows the blade to fold when pressure is applied.
Lockback: Also known as the spine lock, the Lockback includes a pivoted latch affixed to a spring, and can be disengaged only by pressing the latch down to release the blade.
Liner Lock: Uses a leaf spring-type liner within the groove of the handle that snaps into position under the blade when it is deployed. The lock is released by pushing the liner to the side, to allow the blade to return to its groove set into the handle.
Frame Lock: Also known as the integral lock or monolock, this locking mechanism uses a partial cutout of the actual knife handle, rather than a separate liner inside of the handle to hold the blade in place.
Arc Lock: A locking mechanism exclusively licensed to SOG Specialty Knives & Tools. A cylindrical bearing is tensioned by a rotary spring rather than an axial spring.