What is a gravity knife? Everything you need to know about gravity knives

A gravity knife is a gravity-operated folding knife that opens easily with the help of gravity or centripetal force, after which spring power assists to bring the blade into a locked position. Some gravity knives have a button on the handle to release the locking system and allow gravity to move out an inoperative blade.

Gravity knives also called gravity knives, gravity sticks, or gravity blades, are a type of folding knife with a blade that can be released from its handle into the locked position by gravity and then returned to the handle when desired.

History of gravity knives

History of gravity knives.

The gravity knife was first invented by German Luftwaffe pilots during World War II.

During WWII, gravity knives were used by military personnel to quickly cut braided nylon suspension lines on parachutes after a jump. The speed and efficiency of gravity knives would allow soldiers to quickly pack their parachutes back into their carrying bags. Since this was done frequently it increased the speed at which soldiers could exit an airplane in flight, saving lives.

When not being used for cutting parachute suspension lines, gravity knives have been used as general-purpose utility knives. Gravity Knives are also known as flick knives or flipper knives because of how swiftly they open with a simple flick of the user’s wrist (usually with the help of gravity). Gravity Knives were often considered a status symbol and could be found as a sidearm on World War II soldiers’ uniforms.

How gravity knives work

Gravity knives work through using gravity for the deployment of the blade, some models use gravity or inertia for locking while others make use of springs. The knife’s blade uses gravity for its deployment via a hole at the bottom end where air pressure is applied when swinging it down against gravity which causes it to push out further due to this increased pressure – this enables gravity knives to be easily concealed due to their small size while also making it easier to deploy the blade.

Some gravity knife models share similarities with switchblades (which are illegal according to some states within the United States), these so-called gravity-assisted knives need a button for engaging and disengaging the gravity function which is usually located on its side, this is usually used when opening so that gravity will cause the blade to slide out before pressing a second button in order for it to lock into place. Some other models have a hole at their top end which is used for locking instead of a switchblade’s button, in both cases gravity assists with deploying and locking the knife’s blade – once again if you want to carry one of these knives you need to find out whether your state allows gravity knives.

Types of gravity knives that are often confused

  • George Ibberson & Co. of Sheffield, England produced a British variation of the gravity knife after the German model became popular. It was designed for Special Operations Executive and used as a backup fighting weapon. These knives were identical to the German types, except that they had smooth wooden or plastic grips.
  • Gravity knives are, in fact, switchblades. Switchblades are not only safer than gravity knives; they’re also more advanced. Gravity knives have blades that fall out when the knife is opened; switchblades do not feature this function. The blade of a switchblade opens automatically with the help of spring after a button is depressed (this is known as “automatic transfer”).
  • The butterfly knife, which is modeled after the gravity knife, differs in several aspects. The butterfly knife relies on hand motions instead of gravity. The handle of this pocket knife is divided into two pieces that can be opened like the wings of a butterfly. When opening the handle by moving the two parts apart from each other, the blade is revealed within.
  • Other knives similar to the gravity knives are OTF knives, penny knives, etc.

What is the gravity knife’s legal status?

What is the gravity knifeā€™s legal status?

Gravity knives are classified in most countries’ legal systems as either switchblades or gravity-assisted knives with most states within the US including them under their prohibited weapons list, but some states allow gravity knives for people who possess the relevant licenses (check with your state’s laws to make sure). Law enforcement authorities will try to fit gravity knives into the switchblade category, this means that if you purchase one of these weapons without having a license then it will be illegal for you to carry or use it – even when traveling across state lines. If they do not deem gravity knives illegal they may treat them like any other knife, gravity knives are usually subject to the same knife laws as regular knives.

Laws about gravity knives in different states and countries vary greatly. The gravity knife generally falls under the category of prohibited weapons, but even this is difficult to discern due to the fact that gravity knives are often lumped in with switchblades or automatic knives based on similar appearances.

A gravity knife is designed for one purpose: quick and effortless deployment with one hand using the centrifugal force of gravity – hence the name gravity knife. Utilizing gravity to deploy the blade requires no wrist snap, flicks, buttons, or switches. Outfitted with a small internal locking mechanism (or none at all), gravity knives employ gravity as their sole means of holding the blade safely closed within the handle until ready for use. This makes it easy to pocket carry even when wearing form-fitting clothing like jeans, slacks, or suits.

Gravity knives are often confused with switchblades and automatic knives because gravity knives use gravity as a means to open the blade similar to a switchblade and also only requires the user only to apply pressure on an exposed portion of the blade in order to cause it to extend. Unfortunately for gravity knife owners, this is considered a prosecutable offense due to misunderstandings about gravity knives as well as ignorance about how gravity knives work. Gravity Knife law can be further complicated by laws that target specific brands or looks of gravity knives. For example, gravity knives that look like Balisong knives may fall under Balisong Knife law even if they do not work like a Balisong knife.

States That Classify Gravity Knives As Illegal

Switchblade Knife law also applies to gravity knives, but gravity knives are often treated separately due to their separate operational mechanisms.

The gravity knife is classified as an illegal weapon in the following states:

  • New York gravity knives are considered switchblades if they have a blade that can be opened automatically by gravity or centrifugal force. Because of this, simple possession of a gravity knife in New York may result in criminal charges for criminal possession of a weapon in the fourth degree (PEN 220.00). This crime is usually prosecuted as a class A misdemeanor punishable by up to 1-year imprisonment and/or a $1,000 fine. However, carrying gravity knives with locking blades or manufactured as Balisong-style gravity knives are prosecuted as a class D felony punishable by up to 7 years imprisonment and/or a $5,000 fine.

  • New Jersey gravity knives are also considered switchblades if they can be opened automatically by gravity or centrifugal force. Because gravity knives fall under New Jersey switchblade law, simple ownership of gravity knives is punished with criminal charges for possession of an illegal weapon (N.J.S.A 2C:39-4) which makes gravity knives illegal weapons in the state of New Jersey. This offense is typically charged as a fourth-degree crime, but gravity knives that have locking blades are sometimes charged as third-degree crimes depending on the facts surrounding the case. Fourth-degree crimes are punishable by up to 18 months jail time and/or a $10,000 fine.

    Third-degree crimes are punishable by up to 5 years imprisonment and/or a $15,000 fine.

    Safety gravity knives (knives that open with gravity or centrifugal force without locking blades) are legal in the state of New Jersey. However, gravity knives that look like Balisong gravity knives can be prosecuted under Balisong Knife law if they do not work like a Balisong knife.

    Blade Length: The blade size of an illegal gravity knife does not matter for New Jersey and New York gravity knife laws. However, gravity knives with larger blades tend to be more expensive and cumbersome. As a result, gravity knives with blades longer than 2.5 inches are generally reserved for professional use while gravity knives with blades shorter than 2.5 inches are common among gravity knife owners and easier to conceal.

    New Jersey gravity knife law enforcement focuses more on the blade size of gravity knifes rather than gravity knives themselves because gravity knives without locking blades cannot be opened by centrifugal force alone and thus can only be opened manually. Thus, gravity knives that look like Balisong gravity knives (i.e., gravity knives that work like Balisong gravity knives) tend to have blades less than two and a half inches in length despite the fact they may not technically fall under New Jersey gravity knife law.


Why is a gravity knife illegal?

The problem with gravity knives is that they are considered concealed weapons because their defining characteristics make them easy to hide, and they can be opened quickly--making them dangerous instruments in self-defense.

What is a gravity knife used for?

A gravity knife can be used for a multitude of purposes but also has restrictions. In the US, gravity knives are illegal if they have a blade that is over 2 inches when extended from the handle.

What states are gravity knives illegal?

It is illegal to carry gravity knives in the following states: Alaska, California, Florida, Illinois, Kansas, Minnesota, Missouri, Nevada, New Jersey, New York, North Carolina, and Tennessee. It is also illegal to sell gravity knives in the following states: Minnesota, Missouri, and Tennessee. In the remaining 45 states, gravity knives are legal for ownership but remain illegal to carry concealed or open if you're a convicted felon.