Gravity Knife

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Gravity Knife

Published: December 27th, 2024

The concept of the gravity knife traces its roots to the 18th century when early examples appeared in various forms. However, the modern gravity knife as we know it today originated in Germany during the 1930s and was developed to meet the specific needs of airborne warfare. German Fallschirmjäger (paratroopers) faced unique challenges when deploying by parachute, particularly the risk of becoming entangled in their rigging lines. A standard folding knife was impractical in these scenarios due to the need for two-handed operation, prompting the design of the Flieger-Kappmesser (flyer’s folding knife) in 1937.

The Type I Flieger-Kappmesser was a groundbreaking design. Featuring a gravity-deployed blade and a folding rigging spike, the knife allowed German paratroopers to free themselves from tangled parachute lines or harnesses quickly. The blade, deployed by pressing a lever and using the force of gravity, could be locked into place for stability. The rigging spike was equally essential, providing a secondary tool for knotwork or prying.

Initially issued to Luftwaffe personnel, the Flieger-Kappmesser proved its value on the battlefield. Its utility extended beyond parachute operations, becoming a multipurpose tool for survival and field tasks. Later models, such as the Type II, incorporated refinements in materials and locking mechanisms, ensuring reliability in combat conditions.

During World War II, British forces captured a number of Type I Flieger-Kappmesser knives. Recognizing their utility, the British government commissioned George Ibberson & Co., a prominent knife and cutlery manufacturer in Sheffield, England, to produce a British version for the Special Operations Executive (SOE) and other clandestine units.

Under the initial contract, 500 Sheffield gravity knives were made, closely modeled after the German original. These knives featured either smooth wood or textured plastic scales, with a gravity-deployed blade and a folding rigging spike or awl. Despite their similarity to the Flieger-Kappmesser, the Sheffield gravity knives found distinct applications in covert warfare.

Flieger-Kappmesser (flyer's folding knife)

- The "modern" gravity knife originated in Germany as a knife for German Fallschirmjäger (paratrooper)

- The Flieger-Kappmesser (flyer's folding knife) (pictured above) was developed in 1937

Ibberson Gravity Knife

- During WWII the British commisioned George Ibberson & Co to replicate the Flieger-Kappmesser knives

- The Ibberson Gravity Knife (pictured above), were utilized by the British SOE operatives

In the hands of SOE operatives, the gravity knife was considered a secondary combat weapon. Instructors noted that the folding rigging spike could be employed for silent sentry elimination by targeting the carotid artery. This dual-purpose design made the Sheffield gravity knife invaluable for sabotage missions and other covert operations.

Following World War II, gravity knives gained popularity among civilians, collectors, and various military organizations. The designs became symbols of military ingenuity, with many surplus knives finding their way into the hands of collectors. The German-made gravity knives, particularly the wartime models, became prized artifacts of military history.

The widespread availability of gravity knives post-war brought with it a new wave of controversy. Often lumped into the same category as switchblades, gravity knives were portrayed in the media as dangerous weapons associated with crime, despite their utilitarian origins. This portrayal contributed to legislative efforts aimed at regulating or outright banning gravity knives.

In the United States, the Federal Switchblade Act of 1958 restricted the interstate commerce of automatic knives, including gravity knives. State and local governments followed with their own laws, some of which adopted vague definitions that led to arbitrary enforcement. For example, New York State’s gravity knife laws relied on a "wrist-flick test" to determine legality, resulting in thousands of questionable arrests until the law was repealed in 2019.

Despite legal restrictions, the gravity knife remains popular among collectors and enthusiasts. Modern manufacturers have reimagined the design, introducing contemporary materials and engineering to enhance performance and aesthetics. Companies like Reate Knives have produced high-end gravity knives, such as the Exo series, blending historical design with cutting-edge technology.

At its core, the gravity knife’s defining characteristic is its deployment mechanism. Unlike switchblades, which rely on springs, gravity knives use a sliding mechanism and the force of gravity or centrifugal force to deploy the blade. This simple yet effective design reduces the risk of mechanical failure, making the knife reliable in adverse conditions.

The original German models included a lever for blade deployment and locking, a robust handle, and a folding rigging spike. Modern adaptations have refined these features, often incorporating lightweight materials like CNC aluminum, titanium, or carbon fiber for improved durability and portability.

Reate logo

- Today, companies like Reate have helped popularize the gravity knife with their Exo series

The history of the gravity knife is one of innovation meeting necessity. Originally devised as a life-saving tool for paratroopers, it evolved into a versatile instrument embraced by various user groups. As knife enthusiasts and historians continue to explore the gravity knife's rich past, its story serves as a reminder of how tools can bridge the gap between practicality and art, necessity and invention. Whether as a collector’s item, a survival tool, or a modern reinterpretation, the gravity knife holds a unique place in knife history.

Written by Drew Clifton

What to Buy

The Reate Exo Mini Gravity Knife is a compact, innovative tool designed for precision and style. It features a 2.5" CPM 3V tool steel dagger blade with a stonewash finish, offering durability and sharpness for a variety of tasks. Its unique pivoting frame and reverse-positioned button lock make deployment smooth and intuitive, just a flick of the wrist, and gravity does the rest. The bead-blasted titanium handles, accented with burlap Micarta inlays, provide a blend of modern aesthetics and secure grip. Measuring 3.7" closed and weighing only 3.8oz, this knife is perfect for everyday carry. A bead-blasted titanium pocket clip ensures secure and convenient storage.

The Reate Exo-U Gravity Knife combines precision, style, and innovation. Its 2.4-inch stainless steel Wharncliffe blade ensures clean, controlled cuts, while the dual black and gray finish adds durability. The gravity deployment system offers quick, effortless blade access, secured by a black button lock for safety. The green diamond-patterned aluminum handle delivers a rugged grip and striking aesthetic, perfect for EDC enthusiasts. Compact at 3.5 inches closed and weighing just 2.55 ounces, it includes a black tip-down pocket clip for secure carry.

The Reate Exo-M Gravity Knife combines precision engineering with a 3.7" Elmax powder steel drop point blade, dual satin and black finish, and an innovative gravity deployment system. Featuring a safety lock for added protection, titanium handles with Micarta scales, and a smooth out-the-front mechanism, it offers reliability and ease of use. Compact at 4.9" closed and 5.07oz, it includes a black leather sheath with a belt loop, stickers, and a microfiber cloth. This knife is a premium addition to any collection or everyday carry.

Expert Reviewed

T.C. Barnette

T.C. Barnette

T.C. Barnette is a dynamic media personality and the esteemed spokesperson for SMKW (Smoky Mountain Knife Works), where his passion for knives intersects with his captivating on-screen presence. With a magnetic charisma and deep expertise in cutlery, T.C. has become a beloved figure in the knife community.

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