An OTF Knife, also known as an out-the-front knife, sliding knife, telescoping knife, or angel blade, is a

pocketknife A pocketknife (also spelled as pocket knife) is a knife with one or more blades that fold into the handle. They are also known as jackknives, folding knives, Everyday carry, EDC knife, or may be referred to as a penknife, though a penknife may a ...

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 Sharpness (cutting), sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they a ...

slides parallel with the handle to deploy.

Switchblade A switchblade (also known as switch knife, automatic knife, pushbutton knife, ejector knife, flick knife, gravity knife, flick blade, or spring knife) is a pocketknife with a sliding or pivoting blade contained in the handle which is extended ...

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 the knife 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 Stone Age, 2.5 million years ago, as e ...

. The term "Slider" is usually not applied to automatic knives. 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 German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

paratrooper knife of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. 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 A red star, five-pointed and filled, is a symbol that has often historically been associated with communist ideology, particularly in combination with the hammer and sickle, but is also used as a purely socialist symbol in the 21st century. ...

handle was sold in the

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, claimed to be a

police The police are Law enforcement organization, a constituted body of Law enforcement officer, people empowered by a State (polity), state with the aim of Law enforcement, enforcing the law and protecting the Public order policing, public order ...

knife from the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. 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. In the US, 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