Knife Shown:
Kershaw Leek

An assisted-opening knife bridges the gap between manual folders and automatics. The user begins opening the blade manually using a thumb stud, flipper tab, or opening hole. Once the blade rotates past a detent that holds it closed, an internal torsion bar or coil spring assists the remainder of the opening arc. Unlike an automatic, the blade cannot deploy without direct pressure on the blade itself.

Assisted mechanisms became widely popular in the late 1990s as manufacturers sought faster one-handed deployment without falling under automatic knife definitions in many jurisdictions. These knives typically incorporate modern locking systems such as liner locks or frame locks and often ride on washers or bearings for smoother pivot action. Assisted designs are now common in everyday carry, combining mechanical speed with relatively simple internal construction.

Knife Shown:
Pro-Tech/SMKW Godson

An automatic knife uses stored spring tension to deploy the blade when a button or actuator is pressed. In a traditional side-opening automatic, the blade pivots from the handle on a hinge, much like a manual folder, but a coil or leaf spring drives it open once released. A plunge lock, typically a spring-loaded steel bar engaged by a button, secures the blade in both the open and closed positions. This system allows true one-handed operation without manual blade movement.

Automatic knives saw increased development in the early 1900s, particularly by George Schrade. Their legality has fluctuated over time, especially in the United States under mid-century federal restrictions, though many states have since revised those laws. Modern automatics benefit from precision machining, improved spring materials, and tighter tolerances, resulting in greater reliability and structural integrity than early examples.

Knife Shown:
Lovins Customs Strix

The balisong, or butterfly knife, uses a split-handle construction rather than a single-handle scale-and-pivot system. Two handle halves rotate around pivot pins attached to the blade tang. When closed, the handles enclose the blade completely. When opened, the handles swing into alignment to form a single grip behind the blade, usually secured by a latch.

Historically associated with the Philippines, particularly the province of Batangas, the balisong’s exact early history is debated, but its modern form gained international attention in the 1900s. Mechanically, the balisong differs from other folders because the blade does not pivot independently within a frame. Instead, the handles move around the blade. Modern balisongs often use bushings or bearings at the pivots to control blade play and improve smoothness. While functional as cutting tools, they are widely known for manipulation techniques that rely on precise balance and handling.

Knife Shown:
Reate/SMKW EXO-M

The Gravity knife relies on centrifugal force or a simple downward flick to deploy its blade once a locking lever is disengaged. Unlike an automatic knife, it lacks a powered spring; instead, it uses a free-sliding blade that drops into place with a satisfying mechanical "clack." This design rose to prominence during World War II as a specialized tool for the German Fallschirmjäger (paratroopers). These soldiers needed a reliable, one-handed cutting tool to free themselves from tangled parachute lines, a task where a traditional two-handed folder would be useless.

While historical models were utilitarian and blunt, the design has seen a high-tech renaissance in recent years. Makers like Reate Knives have redefined the category, using precision machining, designs, and premium materials like titanium and Bohler Elmax steel to create "modern gravity" folders. These new versions, such as the Exo series, have turned a once-obscure military tool into a centerpiece of modern EDC, proving that gravity is still one of the most reliable deployment methods available.

Knife Shown:
Spyderco Para Military 2

Modern folding knives refer to designs built with modern materials, precision machining, and engineered locking systems. Unlike traditional slip joint knives, most modern folders incorporate positive locking mechanisms that secure the blade during use. Common systems include liner locks, frame locks, axis-style crossbar locks, compression locks, and button locks.

Opening methods are typically optimized for one-handed use, with thumb studs, flippers, or opening holes. Pivots may run on phosphor bronze washers or ball bearings for smooth action. Blade steels frequently include high-performance stainless or powder metallurgy formulations designed for improved edge retention, toughness, and corrosion resistance. G10, micarta, titanium, aluminum, and carbon fiber handle scales are widely used, often paired with stainless steel liners or full titanium frames. Pocket clips are standard, allowing secure carry. The modern folding knife emphasizes structural strength, ergonomic shaping, and efficient deployment, making it the dominant category in EDC knives.

Knife Shown:
Leatherman Arc

The Multitool is the "Swiss Army" philosophy taken to its conclusion. Its history dates back to the late 19th century, when the first iconic red-handled knives integrated blades, screwdrivers, and openers into a single, pocketable frame using a clever system of layered backsprings.

By the mid 1970s, Leatherman had evolved the design into the plier-based powerhouses we see today. These modern versions flip the script, using folding handles to conceal a central set of pliers while tucking saws, files, and drivers into the sides. While a dedicated folding knife focuses on the perfect cut, the multitool focuses on the total solution, trading a bit of blade ergonomics for the ability to fix a loose screw or nip a wire on the fly.

Knife Shown:
Microtech Ultratech Gen III

Out-the-front knives deploy the blade straight forward through the front of the handle rather than pivoting from the side. Most OTF knives are automatic and use an internal spring and rail system. In single-action designs, a thumb slide deploys the blade, but it must be manually reset into the handle to re-cock the mechanism. In dual-action designs, the same thumb slide both deploys and retracts the blade. Internally, a spring-driven carriage engages the blade tang and moves along guide rails cut into the handle chassis.

Because the blade travels in a linear path, OTF knives require precise machining to maintain alignment and minimize lateral play. Early OTF designs were sometimes fragile, but advances in materials and manufacturing have improved durability. The straight-line deployment can be useful in confined environments where a rotating blade might be obstructed.

Knife Shown:
Case XX Trapper

The Traditional folding knife stands as a masterclass in the philosophy that if something isn’t broken, you don’t fix it. These knives rely on time-tested patterns that predate modern locks, commonly using a slipjoint mechanism where a tensioned backspring holds the blade in place. Most include a "half-stop", a notch at the 90° mark, to ensure the blade doesn't snap shut on your fingers during use.

Classic patterns like the Barlow, Stockman, and Trapper were born on 19th-century ranches and workshops, and were tailored for specific trades. With handles crafted from jigged bone, hardwoods, or rugged stag, traditional pocket knives offer a soul and "pocket feel" that modern tactical knives rarely replicate. They require two hands and a bit of patience to open via a nail nick, favoring a slower, more intentional pace of work.