The locking system of a folding knife determines its safety and ease of use: it stops the blade closing on your fingers while you cut. The main mechanisms are the slip joint, which holds the blade without locking it, the back lock, the liner lock, the frame lock and brand-specific systems such as the Axis Lock or the button lock. For everyday use, they are all valid: the right choice depends mostly on your habits and your hands.
Why the lock matters
A folding knife works on a pivot. Without a lock, pressure on the spine of the blade or a twisting force can close it. A reliable locking mechanism makes the knife safer for everyday tasks: opening a cardboard box, cutting a rope, preparing a picnic or trimming a branch. It also affects how you open and close the knife, with one hand or two.
The slip joint
This is the oldest system, the one found on most Swiss Army knives and many regional knives. A spring pressed against the heel of the blade holds it open or closed, but without locking it: with enough force, it closes.
The Spyderco UK Pen is a fine modern example. With this type of knife, you quickly learn to cut by pressing on the edge and never on the spine of the blade. For Swiss Army knives, see our guide how to choose a Swiss Army knife.
- Strengths: simplicity, slimness, tradition.
- Limits: no true lock.
The back lock
A spring located in the spine of the handle drops into a notch in the heel of the blade. To close it, you press the part of the spring that protrudes from the back of the handle. Sturdy and proven, this is the system of the famous Buck 110, a benchmark folding knife for decades, and of many Spyderco knives such as the Delica.
- Strengths: very strong, easy to understand, ambidextrous.
- Limits: closing often takes both hands.
The liner lock
A metal strip, cut from the inner liner of the handle, moves behind the heel of the blade as it opens and locks it. To close, you push this strip to the side with your thumb. It is a common system on modern pocket knives, such as the Kershaw Shuffle II, whose ring also works as a bottle opener.
- Strengths: one-handed closing, compact mechanism.
- Limits: generally designed for right-handers, to be checked before buying.
The frame lock
The same principle as the liner lock, but it is a part of the handle itself, often steel or titanium, that acts as the lock. The result is thicker and more rigid. The CRKT Squid, with its steel handle, shows this system well in a compact format.
- Strengths: very rigid, few parts.
- Limits: knives are often heavier.
Brand systems
The Axis Lock (Benchmade)
A small bar, pushed by springs, slides in a slot in the handle and locks the heel of the blade. By pulling the bar back, you release the blade with one hand, whether you are right- or left-handed. The very light Benchmade Bugout is fitted with it.
The button lock
A button on the handle locks the blade; you press it to release it. On the Civivi Elementum Button Lock, it locks the blade in both the open and closed positions.
The Virobloc ring (Opinel)
Simpler still, Opinel's rotating ring locks the blade in the open position from the N°6 upwards. A rustic system that has proved itself since 1955.
How to choose?
- For light, traditional use: a slip joint, discreet and pleasant.
- For everyday robustness: a back lock or a frame lock.
- For ambidexterity and one-handed operation: an Axis Lock or a button lock.
- For a compact format: a liner lock.
Whichever system you have, check regularly that the lock engages firmly, without play, and keep the mechanism clean. A drop of oil on the pivot from time to time is enough. Discover our selection in the Folding knives and Branded pocket knives collections.
Frequently asked questions
Which is the safest locking system?
A well-designed back lock, frame lock or Axis Lock all offer an excellent level of safety for everyday use. Build quality matters more than the type of mechanism.
Is a slip joint knife dangerous?
No, if used correctly. The blade is not locked: you cut by pressing on the edge, never on the spine of the blade.
Which system for a left-hander?
The back lock, the Axis Lock and most button locks are ambidextrous. Liner locks and frame locks are often designed for right-handers.
How do you look after the mechanism?
Clean the handle to clear out dust and residue, dry it, then put a drop of oil on the pivot. Check that the lock engages without play.
What is a "flipper" knife?
It is a way of opening, not of locking: a tab at the back of the blade lets you open it with a press of the index finger. It is paired with a locking system, often a liner lock or a frame lock.
Knives are sold only to customers aged 18 and over. Carrying a knife is regulated by law: find out about the legislation in force wherever you take it.