A liner lock is a locking mechanism used for foldable pocket knives. A few years ago this was by far the most common lock and it is still a valid choice with many benefits.


As the name suggests the liner lock makes use of the handle liners. A classic build of folders is made of two scales which make the part of the handle you touch when holding the knife. Most handle materials are good to the touch but not tough enough to work as a handle on their own. So many handles have liners. Either they are the same size as the scales or they lie in “pockets” in the scales. Either way, to make a liner lock, a part of one of the liners is bent so that it jumps behind back of the blade when its open. To close the knife you push the liner back into place so you can move the blade.

Liner lock usually is a very reliable locking mechanism. There are just a few things to consider:

  • The length of the lock must match exactly the length to the blade. The lock is most stable if the locking part is centered in the back of the blade.
  • The notorious “spine whack” test where you hit a hard surface with the spine of an open blade can damage the lock permanently. The material withstands enough force to keep the blade locked. But “whacking” it exceeds everything this mechanism was made for.
  • Depending on the material of the liner it might need an extra layer of hardened steel at the point of contact to the blade. This is more common with a similar locking mechanism: The frame lock.

Variants of liner lock

Since liner lock is very common and proven mechanism there are variants. Like L.A.W.K.S. (and it’s automatic variant) that puts bolt behind the lock so that it can’t open without releasing the bolt before.

Many liner lock double as a way to keep the blade in the handle. They often feature a detent ball that presses into a hole in the blade to keep it shut.