For years, OTFs were seen more as gimmicks for those who love novelty and less as serious, competently designed knives that could function as an everyday carry (EDC) option or acquit themselves well when placed into a self-defense situation. Part of that negative reputation owed to OTFs’ admittedly unique and flashy method of blade deployment, but something more was at work. The early entrants into the market tended to be of lower quality. Cheap components, shoddy construction, and questionable durability combined to create the impression that OTFs were just junk. Today, though, the situation is very, very different. Manufacturers of premium OTFs create aesthetically attractive knives that function exactly as intended each and every time you need to use them. Of course, this begs an obvious question: What differentiates a premium OTF from one of lower quality?

In this article, we will examine two elements that set high-end automatic knives apart, namely their locking and trigger mechanisms. After touching briefly on how OTFs work in general, we will discuss the different types of mechanisms and explain what you should expect when buying a premium OTF.

How Does an OTF Work?

Not all of what distinguishes a premium OTF is apparent from simply looking at these knives’ externals, so it’s helpful to brush up on exactly how they work. Start by visualizing the handle of a closed, double-action OTF, and then imagine that you can see through it. Inside, you’d find the blade, the triggering mechanism (more on that in the next section), and a pair of blade catches connected by a spring. Closer examination would reveal grooves worked into both sides of the handle’s interior, corresponding knobs near the rear of the blade that guide its path as it slides, and latches that keep the blade catches in place.

When a user engages an OTF’s trigger mechanism, it places pressure on the attached spring. Once the spring reaches its maximum tension, the blade pushes the latches aside and shoots forward until the forward-facing catch secures it in place. Tension is once again placed on the spring, and engaging the deployment mechanism causes it to pull the blade in the opposite direction.

There is one type of OTF that doesn’t employ this elegant, symmetrical arrangement, and that’s the single-action OTF. These sorts of knives only automatically deploy the blade and require the user to draw it back into the handle manually. Single-action OTFs tend to be budget offerings, and you generally won’t find such locking and deployment mechanisms on premium options.

Locking and Trigger Mechanisms

All OTFs follow a somewhat similar internal design, but that doesn’t mean that they’re all identical. Several standard variations exist in their locking and trigger mechanisms, variations that can significantly impact the look, feel, and usability of a knife. Following are the major variations you can expect to find when purchasing an OTF.

Tang Lock / Frame Lock

When an OTF’s spring-powered blade shoots forward, a slight spur on blunt end of the blade fits into a catch to halt its movement and lock it in place. If it didn’t, we’d have a ballistic knife on our hands, a weapon that fires a blade like a bullet and that is pretty much universally illegal. OTF blades usually lock in at the tang or farther down on the handle. While indistinguishable when the knife is buttoned up, these two different ways of locking can significantly impact an OTFs usability, which we will discuss in greater detail in our final section.

Spine-Mounted Lever

Another major way in which OTFs differ (and one that is fully evident before you even pick one up) is in the style of employment or trigger mechanism. The most common way to trigger the ejection of a blade is with a lever that slides back and forth on the frame. Raised and textured spine-mounted levers appear frequently and create a noticeable dimple on an OTF’s outline.

Body-Mounted Lever

Levers also turn up on OTFs’ bodies, usually in the middle of a handle and intended to be facing away from the palm. They often don’t rise as high as the spine-mounted variety or have quite as dramatic texturing. Also, some might appreciate that they blend better with an OTF’s overall aesthetic.

Plunge Lock / Button Lock

Our final trigger is one more commonly associated with switchblades rather than OTFs. On newer automatic knives, you’ll find them referred to as plunge locks, but they’re still sometimes dubbed button locks. By pressing down on them, you can swiftly extrude an OTF’s blade. While this might seem advantageous, plunge locks come with several distinct design compromises. In order to avoid accidental deployments, OTFs will often have button locks sit flush with a small housing on the handle. Additionally, plunge-lock OTFs are necessarily single-action knives.

What Distinguishes the Mechanisms of Premium OTFs?

Given that most OTF offerings employ some combination of the mechanisms described above, doesn’t that mean there’s no real difference between these elements in a premium OTF and a bog-standard one? Should you feel free to make your purchasing decision based on whatever catches your eye? Well, perhaps not, and let us explain why.

All blades that fold or retract into a handle run the risk of moving when you don’t want them to, which is why they feature locking mechanisms. While both tang locks and body locks can secure an OTF blade, they won’t necessarily function equally well. Some argue that the length of extrusion allowed by tang locks predisposes them to wiggling, so consider a body lock when looking for stability, particularly in a premium OTF.

At TAKCOM, we offer OTFs with both spine-mounted levers and body-mounted levers, both of which offer specific benefits and drawbacks. The former are easier to operate while also running the risk of snagging on clothing. The latter will prove simple to draw, but you may struggle for purchase when engaging it. No matter the option, a premium knife maker will ensure that both styles are reasonably unobtrusive and offer enough traction to move the lever using a reasonable amount of force. Button locks won’t appear on most premium OTFs since they remove the possibility of single-handed operation.

TAKCOM provides high-end OTF in multiple configurations, everything from our aggressively stylized Nighthawk to our eminently pocketable Stubby, and we carefully craft our locking and trigger mechanisms to ensure the best possible operating experience. Browse our full selection.