An OTF Knife, also known as an out-the-front knife, sliding knife, telescoping knife, or angel blade, is a pocketknife with a blade that opens and closes through a hole in one end of the handle. This design contrasts with the majority of utility knives, which are either standard folding knives or are "fixed blade" sheath knives (having no mechanical operation). "OTF" only refers to the basic portion of the knife's mechanical operation where the

blade A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Histor ...

slides parallel with the handle to deploy.

Switchblade A switchblade (aka switch knife, automatic knife, pushbutton knife, ejector knife, flick knife, Stiletto, flick blade, or spring knife (Sprenger,Benson, Ragnar (1989). ''Switchblade: The Ace of Blades''. Paladin Press. pp. 1–14. . The sw ...

s and gravity knives provide a great variety of different OTF mechanisms.

"Gentlemen's" OTF knives

Illustrated above are four very small OTF knives. Figure A shows simple rocking jaw type button, and Figure B is a roll-lock design. Both figures depict gravity knives that fall open. The leading edge of the roll cap or jaw acts as a hole cover when closed, and rests in a groove milled across the open blade tang in order to lock open. Figures C and D are known as sliders or sliding knives. The knife blade must be pushed with the button along the length of the handle, finger pressure must overcome friction. The lock buttons on C & D are not automatic releases. Figure C is a Christy Cutter (trademark) Details on the Christy Pocket Knife
/ref> and Figure D is an antique design. The simplicity of sliding mechanisms have allowed some knife manufacturers to build extremely thin gentlemen's models, that are very comfortable to pocket.

Automatic OTF knives

An automatic OTF knife blade travels within an internal track or channel in the same manner as a manual slider or gravity knife. But the automatic main spring drive and button mechanism enclosed within requires a switchblade handle to be thicker or longer than a similar size gravity or sliding

knife A knife ( : knives; from Old Norse 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidence ...

. The term "Slider" is usually not applied There are two types of "Out the Front" automatic knives, DA-OTF (double-action) and SA-OTF (single-action). Double-action OTF knives deploy and retract with a multifunction button and spring design. Single-action OTF knives deploy automatically, but must be manually cocked or retracted to close.

Gravity OTF knives

A gravity OTF knife is also not considered a slider, because the blade extends outward by force of gravity or inertia, instead of finger pressure. The most famous gravity knife is the Fallschirmjaeger-Messer, or German paratrooper knife of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. The term gravity knife should primarily reference the Fallschirmjaeger-Messer as the archetypical example.

Spring-assisted gravity knives

Some civilian gravity OTF knives have a small helper spring to kick out the blade. This partial spring drive is not sufficient to classify this type of knife as a switchblade, because it does not drive the blade out to full lock.

Sheath-deployed telescoping knives

Another type of telescoping sliding knife is the Kershaw Ripcord. This is a sheath knife that partially retracts into the handle, and has a small scabbard cap covering the remaining blade tip. The design utilizes a specialized belt hanger/holsters that grasps the retracted blade so the blade is pulled fully open when unholstering. It is a unique compact fixed blade alternative. During the 1990s, a similar sheath-activated sliding knife with embossed Red Star handle was sold in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, claimed to be a

police The police are a constituted body of persons empowered by a state, with the aim to enforce the law, to ensure the safety, health and possessions of citizens, and to prevent crime and civil disorder. Their lawful powers include arrest and th ...

knife from the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. However, no proof of this assertion has been shown.

Roll-lock sliding knives

A roll-lock knife is a type of sliding knife in which the blade rides on a track running the length of the scales, tilting into a detent to lock open or closed. Examples would be the Benchmark Rollox, or its licensed derivative, the CRKT Rollock. Sliding knives like the Rollox are not considered inertia or gravity knife.

Spring-assisted out-the-front knives

Schrade and Smith & Wesson have both recently introduced OTF knives that are opened by sliding forward a handle attached to the blade to engage the torsion spring. As it is classified as spring-assisted, it is not proscribed by the Federal Switchblade Act or most state laws on switchblades.

References

* The AKA, Automatic Knife Association Website * The AKTI, American Knife & Tool Institute standard knife definitions https://web.archive.org/web/20080514111826/http://www.akti.org/PDFS/AKTIDefinitions.pdf * Switchblades of Italy, by Zinser, Fuller, Punchard & Saltzman 2003 Turner Publishing {{Knives Pocket knives