Why Are Gravity Knives Illegal In So Many US States?

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The knife is one of mankind's oldest and most versatile tools, with origins that go back more than 2 million years. Metal blades appeared about 10,000 years ago, and various types of knives are now used for household tasks, to harvest and prepare food, perform surgery, and cut and shape building materials. Similar to how some states have strange laws regarding driving, regulations for knives vary as you travel around the United States. One notable exception are gravity knives, which are banned by federal law in the U.S. Unlike switchblade knives that use a spring system to release the blade with the push of a button or flick of a lever, gravity knives harness inertia to allow users to deploy the blade with one hand. Although they're sub-categorized by opening style and blade type, many gravity knives can be deployed with just a flick of the wrist.

Gravity knives were banned by the Federal Switchblade Act of 1958, which prohibits knives that open "(1) by hand pressure applied to a button or other device in the handle of the knife, or (2) by operation of inertia, gravity, or both." The New York City council passed a comprehensive weapons ban in 1909 that was expanded to include switchblades in 1933; an update to the law banned automatic folding knives even for work purposes in 1956. These laws were meant to protect people from violence involving knives, but violent crimes involving guns are now much more common. In 2023, 1,562 Americans were murdered using knives or similar tools; that same year more than 7,000 murders were committed using handguns. U.S. weapons law might be somewhat stuck in a long-ago era when criminals flashed switchblades instead of Glock pistols, but it's important to know the law and follow it whenever you travel.

Alongside the federal law, the majority of the United States have their own restrictions on the sale and use of automatic knives in terms of type, blade length, who can use them, and how they need to be carried. States where gravity knives have been explicitly prohibited include California, Illinois, Massachusetts, New Jersey, and New York. In the Empire State, gravity knives may only be used by law enforcement or by people actively hunting, trapping, or fishing. These laws vary greatly from state to state, so it's important to do your research before traveling to another part of the country. 

You could face felony charges in some states, including California. There, fixed-blade knives must be carried in a sheath below the waist, and automatic knives with blades longer than two inches can't be carried in public or a vehicle. If you have a Swiss Army Knife, it must be  folded and concealed in a pocket or bag when you're in California. Although laws vary widely from state to state, there are a few consistencies that can help you plan. Even in California, it's legal to carry a folding (non-locking) knife with a blade that's 2.5 inches long or less. We chose the Victorinox Compact model as the best Swiss Army Knife for everyday carrying, but its 3.6-inch blade makes it illegal in that state. In New York and Florida, folding knives that don't fall under the switchblade or gravity knife classification can have blades with a maximum length of 4 inches, and Texas allows folding knife blades up to 5.5 inches long. It's generally safe to carry small blades, but check local laws to make sure your knife and planned use of it are legal in the states you plan to visit.