Fortunately, newer folding knives have added more than merely a pivot point and a finger grip so they can remain open during use. Folding knife designs have multiplied exponentially to the point where basically any kind of folding knife you can imagine is available — and so are some you might not have! Innovations abound, from the truly useful to the wildly artistic to the bewilderingly idiosyncratic. Such diversity owes to variance in a number of factors, which include …

Size. Not every folder is designed to fit in one’s pocket, and you won’t have trouble finding examples with six-inch blades, examples that are every bit as long as most forearms and better suited for slashing through jungle foliage than quartering an apple. Similarly, you can also discover itty-bitty folders with blades little more than an inch, tiny knives intended for quotidian tasks (such as slicing twine) or extreme situations (like slicing free a seat belt or scraping a branch to make kindling).

Locks. While some folding knives don’t lock, most do, and the method of locking can dramatically alter how it functions. We’ve written at length about the most common kinds of folding locks, and that article includes detailed descriptions that we won’t repeat here. Suffice it to say that a folding knife with a slip joint or a ring lock will serve you well in utility contexts, while a button lock or lever lock is more appropriate when you need to deploy a blade quickly. Meanwhile, clasp locks and the ever-popular lever lock do a good job of standing up to increased force during use.

Opening Mechanism. The ways in which users open folding knives also differentiate different designs. Both the oldest types and some created just prior to World War 2 used gravity to deploy the blade. On the other end of the spectrum, spring-assisted knives have used buttons to open famous folding styles such as the stiletto. Other mechanisms between these two options in terms of complexity require the user to make contact with a mechanism near the blade’s spine and manually open the knife. The nail nick is the tried-and-true option that appears on classics such as Old Timer slipjoints, and thumb holes fulfill much the same purpose. Finally, thumb studs allow wielders to deploy knives with such speed that some confuse them with speedy OTF automatics.

Handle Design. The handles of folding knives (indeed, the handles of basically *all* knives) fall into two broad categories: natural or synthetic. But each of those camps contains a manifold number of options. Natural handles may come constructed from bone, horn, leather, cord, or wood — and the types of wood used boggle the mind. Rosewood, oak, ebony, bloodwood, mesquite, blackwood, ironwood, cherry, walnut, maple, birch, bocote, hickory, amboyna, and more. Synthetic materials also offer many different options. Some are inexpensive and durable (polypropylene, polyoxymethylene), and others are pricey, yet formulated to be nigh indestructable (TeroTuf). Some combine attractiveness with usability (Micarta), and others sacrifice looks for toughness (Zytel). Folding knives have so many handle options that one can almost certainly find one with the desired combination of handling, hardness, and aesthetic appeal.

Clip Type. Clips designed to secure a knife in the pocket or on a belt have become common, and even a clip can significantly influence the usability of a knife. For instance, most regular clips are of solid construction and leave the butt of the knife partially exposed, making it easier to drop it. Wire clips remove much of the material, which renders the clip and the knife somewhat harder to spot. Clips made of milled metal are far stronger than traditional ones and difficult to bend, break, or otherwise deform. And deep-carry clips fully conceal a folding knife for maximum discretion.

Blade Type. By now, the theme should be evident: Basically every element of a folding knife comes in multiple permutations. That axiom holds true for blade types as well. Just as they vary in size, so folding knives also vary in style of blade. Drop points, one of the most familiar folding-blade styles, appear on everything from whittlers to tactical knives to EDC options. Clipped blades (where essentially one-third of the material near the knife’s tip has been removed, making an effective stabbing point) and spear points (bilaterally symmetrical blades that are usually sharpened on both sides) are the other two most common blade shapes. However, chisel-shaped tantos based on ancient Japanese designs have gained popularity, and more niche options such as the hook-nosed Wharncliffe and the curled hawkbill have also found fans. And one must also take into account the grind of the blade in addition to its shape, the way in which metal has been removed around its cutting edge to make it sharp. Some common grinds are …

• Hollow Ground: Designed for extremely sharp knives, the beveled section descending to the cutting edge has been removed until it is concave.
• Flat Ground: Used on generalist knives, flat grinds feature a beveled area that’s neither concave nor convex.
• Scandi: A style where the blade starts out unground and then in shaped in a straight, severe “V,” Scandi grinds remain strong over time and are easy to sharpen.
• Chisel: This sort of knife is only ground on one side.
• Hamaguri (蛤): This word originally referred to a specific kind of Japanese clam, and the shape of a hamaguri knife grind resembles that fat Asian delicacy. Essentially the opposite of a hollow-ground blade, a hamaguri bows out and works well when chopping.

Asymmetrical: This is a catch-all terms for blades featuring a different grind on each side. Such knives are intended to tackle different sorts of tasks or to have the strengths of one grind remediate the weaknesses of another