Since the invention of the gravity knife, it is surrounded by controversies because of various reasons. The duration period of the gravity knife is about 50 years and there is a lot of interesting history that you will get to know regarding it in the overview of the gravity knife.

The gravity knife might be controversial but it is a versatile knife with many uses that you can accomplish. We will also enlighten you regarding how the gravity knife works and as well as you will get to know about some types of gravity knives. We also answered some FAQs that will arise in your minds. Keep on reading to know about the in-depth details of the gravity knife.

Overview of Gravity Knives:

Just like the name suggest the gravity knife does have a connection with the earth’s gravitational force. The design of the blade is foldable and it remains within the handle, for unfolding the blade all you have to do is use the motion of your hand and additional gravitational force will help the blade come out of the handle. The thought behind the design of the gravity knife is for quick and easy opening with the help of a wrist flip.

The use of the gravity knife is very common amongst a lot of labourers and carpenters. However, what makes the gravity knife controversial is the law that some governments have for making the gravity knife illegal. There are cases where people who carried gravity knives have been arrested in the past. However, some things changed in the present as the state of New York allows carrying the gravity knife legally.

The origin of gravity knife is in Germany, and the knife was made during the period of World War II. The purpose of the knife was to help German troopers rescue themselves whenever they used to get tangled in the ropes of a parachute. There was always a risk surrounding them because there was a chance that the opposition forces would attack them.

The invention period of the gravity knife was in 1937 was made by the German Air Force. You are yet to know how the German Knife works and we have explained details regarding it below. Have a look at it.

How does the gravity knife work?

The whole working mechanism of the gravity knife depends on inertia and the earth’s gravitational force which causes the blade to release when it is folded. During the era in which the gravity knife was made, the idea of using a spring for releasing the blade was not known.

You can open the gravity knife easily with one hand. The blade is heavier compared to the sheath, so when the gravitational force works on the blade, it easily separates for opening up which seems just like how you see a parachute land. The gravity knife is compact and small in size to easily fit in your pockets.

When you will point the knife toward the ground, the blade gracefully opens up from a folded position. To keep the knife folded when you are not using it, there is a lever that helps you to lock the blade. You can just flip the knife back to its folded position without touching the blade which ensures your safety so there is no chance of accidental cuts. This amazing mechanism of opening the blade using the gravitational force makes the gravity knife easy to carry, use and access.

Even at present times, you will find that the blade of the gravity knife remains folded in the frame that is situated inside a wooden handle. The frame material is metal. You can flip open the blade with only one hand.

Types of gravity knives: 

There are two types of gravity knives. The feature that makes these two types differ from each other is how the blade opens up.

  1. Standard Gravity Knife: The standard gravity knife is similar to most of the folding knives that you find on the market as it has a hinge on the side that controls the opening mechanism of the blade. For opening the standard gravity knife you will need to press a lever that you will find on one side and then flip your wrist. The lever present ensures that the blade does not open up loosely. The inertia caused because of the flipping results in the opening of the blade.
  2. OTF gravity knife: The full form of the OTF gravity knife is out the front. The design of the OTF gravity knife ensures that the blade of the knife can be withdrawn within the hilt of the knife. The position of the lever is present at the top of the hilt which makes the blade slide out. For opening up the blade the lever has to be pulled so that the hilt of the knife moves forward, bringing out the blade while the lever locks the blade in position.


  1. What is the point of a gravity knife?

Ans: The main point of a gravity knife is that the knife can open up with one hand in emergencies with just one flicking movement of the wrist. You don’t have to worry about the knife opening if one of your hands is busy as the gravitational force does the work for you to open the blade.

  1. What makes a knife a gravity knife?

Ans: According to the law of New York, a gravity knife is defined to have a handle that has the blade situated within, which you can bring out by simply flicking your wrist as the gravitational force brings it out.

  1. Are gravity knives legal in the US?

Ans: Not the entire US, but some states do consider gravity knives illegal.

  1. Is a button lock a gravity knife?

Ans: A button lock cannot be considered a gravity knife as there is a need to hold the lock to release the blade which eliminates the idea of requiring gravity for bringing the blade out.

Common uses of the gravity knife:

You can use the gravity knives for many useful reasons, we have listed some common ones. Check them out.

  1. To avoid tricky situations, the gravity knife is used by paratroopers.
  2. The gravity knife is not suitable for fighting yet some people used the gravity knife for combats.
  3. The marlinespike can be used for untangling knots of ropes.
  4. You can use the gravity knife for piercing, fixing, and also cutting.
  5. You can also keep the gravity knife for self-defence as it is compact to fit in any small space.

Where to buy Gravity Knives:


To sum up, the gravity knife is indeed a unique knife that you can add to your collection because of the opening system that is safe and only relies on the earth’s gravitational force. If you are someone who enjoys paragliding, keeping a gravity knife for safety would come in handy just like people used to keep in history.

In situations, when one of your hands is busy, you need a blade to quickly get rid of tangles, a gravity knife will be your saviour. With a simple flicking of your wrist, the blade unfolds with gravitational force and inertia pulling it out from the handle. You will love how the gravity knife is safe to carry since it is lightweight and compact to easily fit in your pockets making it convenient to take it out when you are in instant need.


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