Different Types of Pocket Knives

The 4 Main Types of Folding Knives

Knives are as old as people themselves. According to The Knife Hub, archeologists date the earliest stone knives to 2.6 million years old, and the biblical book of Genesis records the creation of metal implements, saying, “Zillah also bore Tubal-cain; he was the forger of all instruments of bronze and iron.” However, all of these knives had something in common: They were relatively simple in design.

Historians generally trace the invention of the first folding knife back to around 500 B.C. in Europe, and so-called friction knives whose wielders held them open during use through pressure on an extended section of the implement’s tang date to ancient Rome. (In fact, Museum Crush reports that the first known historical example of the Swiss Army knife comes from Rome. This silver knife featured “a spoon, knife, fork and toothpick, a spike used for extracting meat from the shells of seafood and a spatula which could have worked as a toothbrush or for scooping paste from bottles.”) Even though the principle of folding knives has remained the same down the years, today’s folding knives are far more advanced. In this article, we will explain the differences between the four primary types of folding knives.

Slip-Joint Knives

When you think about whittling or the Boys Scouts, the type of knife that likely comes to mind is the slip-joint knife. Indeed, slip-joint knives make for simple everyday carry (EDC) blades. This category of folding knife lacks a locking mechanism, remaining open due to a spring near the pivot point on the knife’s spine. Sometimes these knives are called Barlow knives since the Barlow family of Sheffield, England, was allegedly responsible for their design. In addition to the eponymous Barlow, notable brands include Victorinox, Buck, Kershaw, and Old Timer.

Lockback Knives

Lockback knives are similarly old designs with some dating them back to the 17th century. Unlike slip-joint knives, though, they combine a spring with some sort of locking mechanism, often a latch. But know that applying hard-and-fast rules to this category of knives in dangerous since it’s one of the most diverse categories on the market.

Below you will find some of the most common types of folding knives. Also, check out our folding-knife offerings here at TacKnives.

Linerlock Knives

These knives feature a tensioned piece of metal that slides into a machined groove along the knife’s tang once it has been opened. To close the knife, you must push back the flap of metal and then fold the knife into the handle. These are among the most common and simplest sorts of lockback knives. Frame-lock knives function similarly with the biggest difference being that the handle itself slides against the tang after opening the knife.

Back-Lock Knives

Another common variant, back-lock knives feature a locking mechanism running along the knife’s spine. The base of the blade has a notch carved into it near the pivot, and the mechanism slips in, locking it. A divot near the base of the handle allows users to lift the mechanism.

Ring-Lock Knives

These are simple folding knives that secure the blade in place with a rotating sleeve of metal. Sometimes dubbed a “collar,” this sleeve has a vertical slit in it that allows the blade to fold back into the handle. When rotated to the side, though, its solid section keeps it locked during use.

Automatic Knives

Automatic knives differ in the mechanism they use, but they all have a singular goal: To extend a blade as quickly as possible. This type of folding knife may use kinetic energy or gravitational force to cause the blade to spring out. Because of their ability to deploy quickly, automatic knives are often preferred by military personnel, police officers, and first responders. Note that some states have banned these blades, so before you peruse our selection at TacKnives, check your local laws.

Out the Side (OTS) Knives

As the name suggests, out the side (OTS) knives fold into the handle like most pocketknives and deploy from the grip in a parabolic motion. OTS knives use springs to power the blade, and users can press a button or lever to activate it. If you’ve seen a classic Italian switchblade, you know exactly how an OTS automatic knife works.

Out the Front (OTF) Knives

OTF knives also employ springs and deploying levers or buttons. In almost all aspects, they’re virtually the same as OTS knives. However, the blades extend vertically straight out of the the front of the knife. Since they don’t have to swing out to the side, OTF knives require less clearance to get open than OTS knives, making them more appropriate for use in constricted spaces.

Gravity Knives

Gravity knives look very similar to other kinds of automatic knives, but they operate on a different principle. Whereas OTF, OTS, and variations on the venerable switchblade employ the kinetic force of a compressed spring to eject the blade, the force that makes gravity knives work is right there in the name. These devices originated in World War 2 as parachutists’ tools, a knife that they could deploy one handed should their chutes get snarled, allowing them to quickly free themselves.

Like other knives mentioned above, gravity knives come in multiple configurations. Some lock and some don’t, and the method of blade deployment can include a lever, button, or switch. Note, though, that no matter the design, you’ll have to hold the knife pointing down before the blade will extend!

Butterfly Knives

Our final knife is in a category all its own and needs little introduction. The inimitable butterfly knife originates from Southeast Asia and also goes by the name of “Balisong” or “fan knife.” A butterfly knife features the unique design choice of a vertically split handle with each half secured to its shortened tang. Each handle rotates the opposite direction to enclose the blade, and a small latch holds the handle open or shut. Skilled users can open the blade with a single. More skilled owners have populated YouTube with compilations of complicated knife flips.

Here at TacKnives, we carry many different kinds of folding knife. Check out our selection today!