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12 Different Types of Folding Knife Locks

Different Types of Folding Knife Locks

Types of Folding Pocket Knife Locks

Once you begin studying knives, you start to understand that even relatively small alterations in their design can completely change their end uses. The inclusion of a few additional inches of blade length can move a knife out of the everyday carry (EDC) category and into survival, where extra breadth and heft allow the user to chop and stab more easily. Giving a blade two sharp edges rather than one decisively moves the knife from a utility implement to one intended for combat and similarly unfortunate circumstances where bringing maximized cutting area into play as quickly as possible is of utmost importance. And being able to open a knife by exerting pressure on a lever and engaging a complex arrangement of springs (such as one does with a double-action OTF) aids handicapped individuals, first responders, and other users who only have the use of one hand in a given situation.

One important but often neglected knife element is the type of lock used on a folding pocket knife. Believe it or not, the seemingly simple selection of a particular lock type greatly impacts the way in which one can use a knife. In this article, we will discuss 12 folding knife locks, how they work, and their various advantages and disadvantages.

Slip Joint

Let us begin our discussion of blade locks by talking about a type of knife that, strictly speaking, doesn’t actually *lock*: the slip joint knife. While not the absolute earliest type of folding knife found in the historical record, it still has an impressive pedigree. The first slip joint knives appeared in the middle of the 17th century and boast an amazing variety of styles and brand names. Barlow, scout, dog leg, hawkbill, trapper, and whittler knives all qualify as slip joints. Companies such as Case, Buck, Herder, Marlin, Victorinox, Oldtimer, and Fox Knives also produce slip joints.

There are several reasons why slip joint knives make the list even though they don’t technically qualify as locking knives. First, understanding how slip joints work is essential for comprehending other folding knife locks. Second, a slip joint does hold a knife open with relatively firm pressure, allowing it to function as though it locked in many situations. The inclusion of a spring secreted in the handle keeps the blade either opened or closed. Only by exerting pressure greater than that provided by the spring can the knife be shut or readied.

Spine Lock (aka Back Lock)

The spine lock may very well be the most popular type of folding knife lock in the United States, and it’s a natural evolution from the slip joint. Much like the slip joint, spine locks feature a spring that helps keep the blade closed and facilitates its opening. However, on the pivot point where the blade meets the tang, you’ll find some sort of notch or catch into which a corresponding piece of metal should fall. That metal in question is a thin length situated along the knife’s spine, hence the name. As a user opens the blade usually by working a finger into a nail groove near the blade’s spine and pulling to overcome the blade’s tension, the lock mechanism lifts and then falls into place. A cutaway near the butt of the knife allows the user to press the end of the lock so that it clears the notch, letting the blade fold into the handle.

Spine locks are common because they’re relatively uncomplicated to create and provide excellent stability. However, they’re difficult to open with one hand unless the manufacturer has included a stud or hole near the knife’s pivot point.

Mid Lock

Though often listed as a distinct kind of lock, a mid lock is really just a variation of the spine lock, featuring a slim length of metal that holds the blade open by dropping into an indentation near the pivot point. However, the divot appears in the middle of the spine rather than near the heel of the handle. This shorter column makes the locking action somewhat stronger, and while some argue that the positioning of the divot makes such knives easier to open one-handed, others find it a bit more awkward.

Button Lock

Button locks are nearly as mechanically simple as spine locks, but they’re found on knives that open in varying ways. You’ll find button locks on both automatic and manual knives, and while they’re radically different kinds of knives, the simple button lock remains the same on both. Also known as plunge locks, button locks feature a small button located near the pivot point which pushes a perpendicular stud that’s attached to a spring, locking the blade either open or closed.

One major advantage of button locks is how easy they are to open. They make for excellent one-handed knives no matter if they’re automatic or not. Unfortunately, button locks aren’t anywhere near as sturdy as spine locks and can accidentally open if the button gets pressed while being carried.

Lever Lock

Almost exclusively found on stiletto-style knives, lever locks function similarly to button locks, even though you won’t find them on manual knives. Traditionally, a spring positioned near the blade’s pivot point maintains tension as the blade presses against a pin fitted perpendicularly to the tang. The lever is connected to the pin, and flipping it draws the pin back, causing the blade to deploy. Some lever locks also feature a sort of safety, much like those that appear on firearms; these versions require users to flip the lever and then press down on it to fire the knife.

Knives with lever locks excel at single-handed use and work well ambidextrously. They aren’t very strong, though, and won’t stand up to much force or pressure.

Liner Lock

Another common folding knife lock, liner locks are among the least complex locks mentioned in this article, bested in simplicity by only fiction folders. One could even argue that they’re more basic than slip joints. Liner lock knives feature a spur of metal on the inside of the handle that moves independently of the frame and remains under tension. Users open the blade, and the liner slips to the side, locking into place against the pivot place and keeping the blade from moving. Sliding the liner out of the way with a thumb is all one needs to do in order to disengage the lock.

While liner locks are generally quite strong and reliable, poorly made examples do exist and are prone to failure. Some liners also include a spring to help keep the metal under pressure, which adds another potential failure point. Liner locks aren’t ambidextrous, meaning that lefties will have to make sure they’re purchasing the right knife. And strong blows or particularly hard use may cause the liner lock to slide out of place, destabilizing the blade. Still, liner lock knives are easy to make and simple to use, which makes them a favorite the world over.

Frame Lock

Virtually identical to liner locks in function if not design, frame locks forgo the spur of metal slipped into the handle, making a section of the frame itself into the lock. Most frame locks have a small cutaway that allows a section of the handle to serve as a liner. They’re also often made of titanium, which won’t deform under regular, variable tension. They offer all of the same benefits and drawbacks as liner locks with the added wrinkle of some models having convoluted designs that make operating them a bit awkward.

Ring Lock

For more than 125 years, the company Opinel has stood for French knifemaking, claiming users from every social strata. Agricultural workers adopted Opinel blades, as did Pablo Picasso. They have always been highly practical knives, and n element of them encapsulates that as much as the ring lock, an innovation that the company introduced in 1955. Though it has since spread to other brands of knives, Opinel featured the original version, although its design is hardly complex. A metal ring fitted around the knife’s bolster both rotates and features a slit through which the blade can move. Twist the ring, and the knife remains open or closed.

Decent quality knives with a ring lock can be found at affordable prices due to the lock’s simplicity. Ring lock knives are also fairly easy to ready with a single hand. However, their strength is somewhat lacking, meaning that ring locks are only appropriate for utility-style knives.

Clasp Lock

French fur traders preferred clasp lock knives, and it’s easy to see why: The locking mechanisms on these styles of knife are simple, robust, and strong. Unlike slip joints, clasp locks don’t have springs to aid them in remaining open. Instead, they feature a finger of metal or even a ring on the exterior of the knife near the pivot that’s connected to an interior post. Once fully opened, the post drops into a corresponding slot in the blade. In order to close the knife, one must manually lift the clasp prior to folding the blade.

Clasp locks are relatively tough and can endure long use. Still, they’re difficult to ready using just one hand, and the way the clasp juts from the handle makes them prone to snagging on clothing.


A branded offering from Benchmade Knife Company, the AXIS lock is in the same family as the spine lock, but the way in which the idea is implemented certainly sets it apart. It employs a straight-pushing spring that assists the user in opening the knife, but it doesn’t feature any sort of spine-mounted release. Instead, a cutout next to the bolster houses a small switch connected to a steel bar. When opened, the spring helps guide the blade to a fully extended position, causing the bar to click into a corresponding slot on the blade’s pivot. Pulling back on the switch moves the bar so that the blade can swivel closed.

AXIS locks are designed to remedy the difficulty in opening a spine lock with one hand. Knives with this type of lock almost always include a thumb stud to aid easy, ambidextrous opening. There are really only two downsides to AXIS locks. First, their springs lose strength with time. Second, they tend to be rather expensive when compared to other options.

Tri-Ad Lock

The Tri-Ad lock is another branded option that also riffs on the traditional spine lock, as well as on the mid lock. Glancing at a knife with one of these systems, you could be excused for thinking that it remained exactly the same since you can’t tell the difference from externals. A Tri-Ad lock looks identical to them. However, the guts of the knife are quite different, particularly the slotted section in the pivot near the tang. Instead of a simple latch, Tri-Ad locks have a puzzle-like insert that looks a little like a hammer. This close, oddly shaped fit combined with an added stop pin make Tri-Ad locks incredibly stable. The only real downsides to these knives are their price and the fact that they’re only offered by a single manufacturer.

Compression Lock

The Spiderco compression lock is our final branded lock, and this one avoids the spine-lock template, selecting instead the tried-and-true liner lock. One of the elements of a liner lock that makes it somewhat difficult to use is the fact that you must reach under the handle in order to disengage it. The compression lock moves the position of the liner to the handle’s spine and connects it to a spring. When compressed, it moves a slim piece of metal into a gap between the tang of the blade and a strategically positioned spur on the blade. Super secure a relatively mechanically simple, compression locks are marred by the same downsides as the Tri-Ad lock: They appear on expensive knives produced by a single company.

TacKnives offers many different kinds of folding knives with varying types of locks. Browse our selection today!

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