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The Difference Between Assisted and Automatic Opening Knives

Automatic knives (also known as switchblades) and assisted opening knives are often confused with one another, because they tend to look the same to the untrained eye and are functionally similar. However, understanding the difference between these two knives is important. This is because switchblades are regulated or even illegal in some states and localities in the U.S. whereas assisted knives are legally considered no different from regular pocket knives in most areas.

How an Automatic Knife Works

An automatic knife, is a knife in which the blade springs open when a button on the handle is pressed. When closed, the blade is under continuous tension from a spring, being held closed by a button, switch or other mechanism. When the button is pressed, the tension on the blade is no longer held in check and the blade moves to the open position.

There are two general types of automatic knives, the folder, and the OTF (Out The Front). The folder design is only a slight departure from a standard folding knife, in that it adds a simple spring to force the blade open as soon as the button or switch is released.  The OTF knife is however, an almost universally automatic design. In this design, when closed, the blade is fully contained within the handle, sliding forward and backward to open and close the knife, much like a pen opens and closes.

How an Assisted Opening Knife Works

An assisted opening knife, sometimes called a spring-assisted knife, is a knife that springs open only after the blade is slightly pushed open with force from the user.

Unlike the automatic design, there is no mechanism physically blocking the blade from moving when it's in the closed position. The knife is held closed only by internal spring resistance, usually provided by a second spring opposing the main spring. This is often referred to as a "bias towards closure". As the user begins opening the knife by pressing on a thumb stud or flipper lever attached to the blade, this internal resistance is overcome, and the main spring or torsion bar catches the blade and propels it to the open position where it locks into place.

So Which is Better?

In practice, the operation of folding knives in both categories is almost identical in everyday use, with the only difference being what part of the knife you push to open the knife. A commonly mentioned benefit of the OTF design is that is is easily closed with one hand, by simply pulling back on the switch much as one would to open it. Alternatively, an assisted or automatic folder is usually almost as easily closed one handed, by releasing the locking mechanism and pressing it closed against one's pant leg, or any stationary object. Assisted knives benefit from simplified legal implications in most places and may give the user more peace of mind. Though sometimes hotly debated, for the most part, the answer to this question comes down to personal preference and the needs of the individual user.

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