Automatic Knives: What to Consider When Shopping for One

Automatic Knives: What to Consider When Shopping for One

Posted by Clayton on Feb 25th 2016

Knives come in a variety of styles and sizes, and are intended for a myriad of uses. From the box-cutter knife to the meat cleaver, knives are an essential tool—hence the creation of portable knives in case anyone needs to use one for a particular task or an emergency.

Automatic knives, originally designed for military, law enforcement, and emergency responder use, have single or double action mechanisms that deploy the blade with a simple push of a button or by moving a lever with your thumb.

Today, these knives have become popular with the general public. The opening mechanisms, the way the blade deploys, blade lengths, and sizes vary considerably. If you are in the market for an automatic knife, here are a few things to consider before finalizing your purchase.

OTF (Out The Front) Knives

An out the front blade springs out directly from the handle. A single action OTF, often called a switchblade, requires the user to manually retract the blade. These types of OTFs have stronger springs to keep the blade inside the handle. A double action OTF can retract the blade with the press of a button.

When the knife is closed, there is tension on the blade while it remains locked inside the handle. When a button or slide is pressed, the blade springs out.

You can tell a switchblade from an assisted opening knife (see below) and other knives by the position the blade rests in. If you don’t see anything blocking the blade when it is inside the handle, it is not a switchblade. Also, if the blade opens without any real effort on your part and has a button that deploys the blade, it is likely a switchblade.


If you are able to opt for a switchblade in your state, the type of spring, along with blade quality, is one of the most important things to consider. A switchblade relies on its spring to operate.

Given that the spring in a switchblade is constantly under tension when it is closed, which is most of the time, the springs eventually must be replaced. Springs are not quite as critical with assisted opening knives. The springs do not wear out as easily.


Assisted Opening Knives

Many knife enthusiasts choose assisted opening knives instead of switchblades due to the difficulty in obtaining a switchblade legally. Federal and state governments regulate the sale and possession of switchblades.

These types of knives also use a spring, and are called spring-assisted knives. The knife blade deploys with the assistance of a spring mechanism. Unlike a switchblade, there is no spring under tension when the knife is closed.

When the knife is in the closed position, the user must use a thumb stud or lever. The stud or lever has some resistance provided by a spring. The torsion bar catches the blade once you press down the stud or move the lever, and the blade is propelled out of the handle. The blade then locks in place for use.

Side Opening

A side opening knife has a blade the folds into the handle from the side. Some of them deploy using gravity. You flick your wrist, and the blade pops out and locks in place. Other automatic knives use various types of release mechanisms to deploy the blade.


Release Mechanisms

There are lots of different release mechanisms available today for automatic knives. The most common are the lever lock, clamshell, button, toggle and squeeze. It depends on the user’s preference as to what type is best. Pressing a button or sliding a lever, to most people, makes a knife more convenient to use.


The average length of an automatic knife blade is around 3-3 ½ inches. The overall length of automatic knives usually is around 8 inches, though they can be bigger. Single or double edges knives are available. The blades are usually constructed of a type of stainless steel.

CPM S30V is considered a high-grade form of steel ideal for knives. It is easier to sharpen than other powder steels. This type of steel is extremely strong and durable. High-end automatic knives use this type of steel in the blade, which substantially increases the cost. M390 is another very high quality steel that you will find often in brands like Microtech Knives.

Final Thoughts

These are only some of the things you should take into consideration when choosing an automatic knife. Once you determine your basic requirements, use this site to find an automatic knife that matches your personal preference in terms of color, style, and budget.