What Is an OTF Knife? How Out-the-Front Knives Work
An OTF knife is a pocketknife whose blade slides straight out of, and back into, a hole in the front end of the handle. "OTF" stands for "out the front". Instead of swinging open on a pivot like a folding knife, the blade travels in line with the handle. On an automatic OTF, a spring inside the handle drives the blade forward when you work a slide or button. This guide explains how that works, the difference between single-action and double-action designs, and what to check before you choose one.
What "OTF" means
OTF simply describes the direction the blade travels: it moves parallel to the handle and exits through the front. Knives that open this way have existed in several forms. Some are gravity knives, where the blade drops out under its own weight. Others are sliding knives, where you push the blade forward by hand. The OTF knives most people mean today are automatic: a spring does the work once you activate the control.
Our OTF listings describe the action as "out-the-front automatic deployment". You can browse them in our OTF Knives collection.
How the mechanism works: slide, spring, lock
An automatic OTF has three main parts working together:
- The control. A thumb slide or button on the side of the handle. Many of our listings describe the blade deploying "with a push of the slide"; others describe it firing forward when you "press the button". Check the individual listing to see which one a model uses.
- The spring. A main spring inside the handle provides the force that moves the blade. Because the spring and control mechanism are enclosed in the handle, an automatic OTF handle is thicker or longer than a comparable manual sliding knife.
- The lock. Once the blade is out, a part at the front of the handle seats into a groove across the base of the blade to hold it open. When the blade is retracted, that same part covers the opening.
Single-action vs double-action
OTF knives come in two broad designs:
- Double-action: the same control both deploys and retracts the blade using the spring.
- Single-action: the spring deploys the blade automatically, but you have to retract or re-cock it by hand to close it.
Our product listings do not state whether a given model is single-action or double-action. If this matters to you, look closely at the listing photos and details, and contact us before you order so we can answer for the specific model.
OTF vs side-opening automatics
A side-opening automatic has a blade that pivots out from the side of the handle, like a traditional folding knife, but is released by a button and driven by a spring. An OTF blade never pivots; it moves straight forward. Spring-assisted folders are a third type: you start opening the blade yourself and a spring finishes the job. We compare all three, with a table, in OTF vs Side-Opening vs Spring-Assisted Knives. You can browse side-opening and spring-assisted models in our Folding Knives collection.
Blade shapes you will see
Our OTF listings name the blade shape in the title. The most common are:
- Dagger, a pointed, symmetrical blade. Some listings specify a double-edge dagger.
- Tanto, with an angled, squared-off tip.
- Drop point, where the spine slopes down to the point.
- Half-serrated versions of the above, with serrations near the handle.
For what each shape is good at, see OTF Blade Shapes Explained.
Sizes from mini to full-size
OTF knives are usually described by overall length (blade out) and closed length (blade retracted). Examples from our current listings:
| Size | Example listing | Overall length | Closed length |
|---|---|---|---|
| Mini | Mini OTF, Silver Dagger Blade, Blue Aluminum Handle (LE-104BL) | 5.25" | 3.25" |
| Mid-size | OTF, Two-Tone Dagger Blade, Black Zinc Alloy Handle (LE-112SBKDP) | 7" | 4.15" |
| Full-size | OTF, Flag Print Dagger Blade, American Flag Handle (LE-9929LMR) | 9" | 5.5" |
For a fuller comparison, including pocket fit, read Mini vs Full-Size OTF Knives.
Before you buy: check your local laws
Laws on automatic knives, including OTF and side-opening automatics, vary by location, and can cover owning, carrying and blade length. Laws also change. Before you buy or carry an OTF knife, check the current rules where you live and where you will carry it. The American Knife & Tool Institute keeps a summary of laws regarding automatic knives as a starting point, but it is not a substitute for checking your local law.
Where to go next
If you are choosing your first OTF, decide on size first, then blade shape, then handle and carry options (pocket clip, sheath or pouch are listed on each product). Browse the OTF Knives collection. If you have a question about a specific model before ordering, get in touch.
