What is this I hear about liner locks . . .

G

gitarmac

Joined
Jan 20, 2001
Messages
401
. . . being weak? Should I not open and close my liner locks for hours on end like I do my other ones? I'm asking cause I really like my tenacious and it's making me want a spydie just like it with better steel - and a liner lock. The sage looks like a really nice knife, I'm surprized I hadn't read more about it here.

I don't want to spend a hefty amount of money on one if a liner lock wears out fast though. Or maybe I don't care, the sage looks really cool with the carbon fiber scales and flat ground blade!
 
A properly fitted liner lock is actually very strong. When the liner properly engages the blade tang, it is physically stopping the blade from closing in a manner that is very hard to defeat. The problem, however, is that as the lock wears, it moves across the blade tang until the knife either locks up improperly (the liner is obstructing the tang but is all the way to the opposite side, resulting in a looser lockup than when the liner is engaging the tang face to face) or doesn't lock at all (the liner fails to stop the blade from folding).

Because of the design, by definition, as the metal of the lock wears against the blade tang, the lock will move, and the lockup will change. This is why a proper liner lock is angled to provide room for wear as it faces the blade tang. This is also why the LAWKS system was invented -- it's a little piece of metal that blocks the liner so it cannot close.

m16sf-lawks.jpg




Another issue is that, depending on how the knife is gripped, it may be possible to dislodge the liner simply by hodling the knife tightly (depending on the contour of the lock cutout, the size of your hand, and myriad other factors that may be mitigated through proper knife design).

As long as you inspect your locks regularly to make sure the blade tang is properly engaged, and verify that you cannot accidentally disengage the liner by squeezing the handle in your fist, there is not a problem.
 
Much like ANY lock, a crappy one will wear out in a hurry while a good one won't.

If it starts out life engaging the tang past the 1/2 way point OR the tang geometry is wrong (ie flat) then don't buy it. If it has both those problems, run away.
 
A realitively simple (if not crude) fix for that worn linerlock will work if the knife has room.
If the lock is traveling all the way across the tang of the blade so it lodges against the opposite liner, you can epoxy a small piece of shim stock against that opposite liner to 'hold the lock off'.
This will usually line the lock back up with the tang, but will only work if there's room, clearance, etc. It's worked for me in the past.

JMH
 
Actually liner locks are surprisingly strong. Strength is not their weak point. Reliability is another issue depending on types of pressures coming together that can hit it just the right way in use to make it be sometimes easier to defeat than at other times. The best locks are both strong in all the right ways and reliable which is why the Axis lock by BenchMade, the Arc lock by SOG and the ball lock by Spyderco are among the best of locks currently available which are offering the best of both those two things to hope for in your EDC. For many these locks are the best thing to come around in folding knives since sliced bread but they require a lot of machining and small moving parts with small springs set just right compared to the liner and frame locks which will always be more popular just for the simple fact that they do work for most people, are relatively easy to make and have a wider margin of tolerance for everything from the manufacturing stand point. All partly why so many makers and manufacturers as well as end line users love them.

By the way you can open and close your knife all day long. There are some that think the Wave on Emersons contributes to faster wear but I know of nothing out there substantial enough to prove that. Where I think a thin liner lock suffers most based on my own tests and observations doing field testing for some production companies is in the spine whacking trials. This indented the locks severely at times and caused others to sometimes become sticky, on others it increased lock travel inward to where the knives appeared to be well used by looking at them from the stand point of lock wear and on a few others at times it caused vertical play to be noticed. These were severe tests and not real life examples of what can happen in most normal uses but it did show me in a big way that spine whacking a liner lock or frame lock due to the nature of the impact and the forces involved is a not a very good thing to do. In fact I would have to say that spine whacking lockbacks or any other lock type is undue stress and abuse of the lock mechanism and not a good idea.

I advise users of new frame and particularly new liner locking folders to get to know the knives first before going to town with them and make sure the lock is moving in far enough to be relied upon. Its also adviseable on one that you have a question mark about to do some spine pressure tests to insure the lock doesn't slip or move toward release with tip pressure on the blade. (keeping fingers clear of cutting edges of course)

Once you know you can trust it for these things its generally good to go but as has been reported more times than I can recall liner locks can sometimes show their inherant reilability weakness and this has come up many times more with those type locks than others IMO. All can fail though and this advise should be taken across the board with no particular maker or brand in mind.

STR
 
If you already have a linerlock, don't sweat it. Just be careful. If you're thinking about getting a new knife, I'd sure try to find something with a different lock. Cutting in a normal fashion normally doesn't cause problems, but with a linerlock, the first indication that it's failing is that it...well...fails. CRKT's LAWKS is an addition that makes me feel much more secure, but the knife I trust most has an axis lock.

Any lock can fail, but it's surprising how many fail right from the get-go. I always test any knife I'm going to use or carry, and I've seen failures in all types. Flipping open a knife and closing it will cause wear. With a linerlock, you can generally see the wear before it becomes a problem.

I trust frame locks more, and I like lock-backs a great deal. With the LAWKS, I think a linerlock becomes one of the strongest locks. Still, I like that little shim between the liner and the frame.

CRKT_M21_blokada_det.jpg


The Lake and Walker Knife Safety (LAWKS) is a great innovation.
 
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