Growing Fear of Liner Locks

Mar 12, 1999
The last few days I've been reading a growing number of posts seemingly denigrating "liner locks." Liner locks, they say, have failed the dreaded "whack" tests and many knowledgeable knife enthusiasts warn about failure during "hard use" or other dire situations threatening to the digits. Why, even the much-worshipped MT SOCOM (a knife I personally covet) has been, should I say it, "blasphemed" by someone claiming the MA SOCOM failed the spine whack test better than 50% of the time.
Have I, after a considerable investment in liner lock(LL) folders, done nothing more than throw a lot of money away on a tool that will fail me?
Is it possible that the opponents of LLs are unknowingly being influenced by their bias? Have we have lost a little perspective here? It would be helpful if someone could provide a war story or two or three where the LL failed during use (no saturday night special knives). I can't seem to find a frame of reference that can instruct me about what sort of situation calls for something other than a LL.
I don't ever expect to put myself in a situation that requires the use of a knife to extricate myself. However, suppose that happens and all I have is my trusty LL; am I dead meat?

[This message has been edited by Jumbi (edited 13 July 1999).]
Here here. I personally don't care if a knife is a liner lock or lockback. I have tried to get members to tell me if they had a lockfailure or breakage. Only a few told they had a failure and two have had a lockback break. These were do to abuse or poor materials/construction. As long as you get a quality folder, use it sanely, and maintain it, I think you don't have to worry.
Jumbi, I own liner locks and, generally, prefer them. The only failure that I have had was my own dumb fault in doing a "whack" test while pushing on the liner. And that seems to be the crux of the matter: that one may, in certain circumstances, push on the liner and release the blade. Now the knife that did this was a VERY early Terzuola Clipit C15, one that was serial-numbered and had black anodized aluminum scales, hence a very early production of a liner lock. My subjective impression is that later production of liner lock knives tended to make the liner less vulnerable. Please note that this discussion applies only to quality made knives. With bargain specials, all bets are off.

Walk in the Light of God,

Try an apogee it will do the spine test hehehe And dent your wooden desk top a real good one. You have to take into consideration that locks wear. Buy a knife from a maker who takes care of the knife before and after the sale. Also one who gives a damn about performance not $$$$$$$$
$$$$$$come with performance. I am not perfect and Im sure that others out there are not either . Some of us give a damn though!

Web Site At
Take a look!!!

I have a custom liner lock trainer. It is identical to the sharpened folder except for a dulled down blade. I used it for full force thrusts on my heavy bag for about 5 months without any problems, and then it started to disengage with thrusts. I sent it back to be adjusted and it has held strong for months of training now.

I suppose my hard use could be described as "abuse." However, my $20 one-piece aluminum trainer hasn't complained about the punishment.

So the point is that a liner lock can be very effective, but it may need adjustments with hard use.

Thank you gentlemen, I appreciate all of your well-considered input. And, may I add, I agree with your comments.
I suspect that unless the knife is of extremely poor quality, proper care should enable it to withstand that one-time, most trying event where we have to depend upon its performance. I suspect that most of us will never experience that degree of violence that will wreck us and our liner lock. Those who ARE in a position where they must be prepared for such events because it comes with their territory, probably have tools designed especially for whatever they may encounter.
Thanks again
I don't think you're remotely "dead meat"! I think a lot of people draw the wrong conclusions from the lock reliability test reports. One of the most important conclusions is: YOU SHOULD TEST YOUR LOCKS! It's not a safe lock just because it's a Microtech, or a Benchmade, or made by some fancy custom maker. We as users should demand quality and safety, and ultimately we're the ones responsible for making sure our knives are reliable. I feel liner locks can be made safely, and I feel that way because I've tested some liner locks very very hard with no problems. I also know that many liner locks -- or just locks in general regardless of type -- may run into problems if the user works the knife hard.

One important point:

> Is it possible that the opponents of LLs are unknowingly being influenced by
> their bias?

This is a HUGE post hoc ergo propter hoc. Almost to a person, everyone warning about liner locks came from the point of view that liner locks are very reliable, and only switched their point of view as more data came in. And speaking for myself, I'm not an "opponent" of liner locks, in my mind. Rather, I want to point out that 1) people should test their locks, and 2) way too many liner locks are failing tests or failing in use. Liner lock makers clean up their act and make sure their locks are reliable, I'll happily jump back on the bandwagon.

Until then, there's always Darrel's Apogee

Joe, great insight! That's exactly what happened to me. My first liner lock, Mini-AFCK, sold me on one handed knives and liner locks in particular. I was conviced it was the only way to go! One day while sharpening it, it folded and almost bit me. I had never tested it (newbie). After examining it I found I could hold the handle in one hand, press the spine of the blade with the other and watch the liner lock SLIDE across the base of the blade and fail!

It will eventually make it's way back to BM and get fixed.

Then came the Axis lock and I'm in love again! Yes, I tested this one!

"Attitude - the difference between an ordeal and an adventure!"
I have never had a lock-back or a liner-lock fail me. And I have never tested a knife with a spine whack test either, it seems like unjustifiable abuse of quality cutlery.
I familiarize myself with the amount of pressure required to disengage particular locks and then I use said knives with caution and respect, any knife can close on you if you try hard enough.

"All of our knives open with one hand, in case you're busy with the other"

[This message has been edited by Stompy (edited 14 July 1999).]
I have stated before that I am not for or against any particular type of lock, but I must be assured that that a particular knife will hold under stress. And as Joe stated, it just seems like there are many liner locks that are failing all types of stress tests.
That said I do have faith in my AFCK, because I have put it through it's paces and it has passed with flying colors. But it does seem that Microtech's have been failing on a regular basis these days. This is why I have put all of my M/T's away for the time being, at least until Microtech can tell me how to solve this problem(if they can).

No offense meant, but why would you carry a knife that you know has limitations? Are you 100% sure that you will never have to use the particular knife that you are carrying on any given day to save your life?
Jumbi, testing generates much more failures than use because it is intended to simulate stresses that would occur at the optimal level of use so its easy to see how you can have a knife and use it fine for a long time without it every having a problem. It only needs to happen once for you to really wish it had not, and my fingers are far more important to me than that so I will obviously make sure to the best of my abilities that the lock is secure before I use it.

Great comments all!!
Ok, I can't really dispute the advantages of testing; the more info you have, generally the better prepared you are. Perhaps not being an engineer may have something to do with my lack of understanding of the utility of "whacking" a knife on its spine; I mean, when would I ever employ a knife that way? If I were to do a test, I think the way Axel Yup uses his trainer would more closely simulate the type of stresses likely to be encountered when using a tactical folder. Isn't there a more representative test out there that is less destructive?
I fail to see the utility of weakening a perfectly good knife by bringing it to the breaking point thru destructive testing or severe abuse. Perhaps we should be demanding more of the manufacturer by clearly defining our quality requirements and driving them to improve their production processes to the point where their testing will provide us with the assurances we seek. Now, I realize that some would say "we can't rely on them in a situation so imortant." Well, we can't really go around driving our new vehicles into brick walls to test th integrity of the passenger compartment either; at least not frequently.

Nevertheless, It's really disturbing to hear that a knife like a Microtech, touted as being the epitome of quality and designed for use in life-threatening situations is, in fact, potentially unreliable; sorta like discovering that "the emperor has no clothes."
As I see it we need two things:
1) A more reliable, realistic, less destructive, way of testing the integrity of liner locks.
2) Flex our muscles as consumers and demand knives that won't fail.
I've said it before and I'll say it again. The linerlock isn't bad. For the general public, it will more than serve your needs. But for folks who wants to squeeze every ounce of performance out of a knife? Well, they get nit-picky. And that's what you see quite often on here; many knife-knuts getting picky. Of course, by saying that, I am admitting that I am one of them.
I think that alot of the fear of linerlocks comes from the testing we do on our own knives. Not everyone whacks them, but I think just about everyone does the little blade wiggle test, both horizontal & verticle, and I have seen Linerlocks want to fold with just that alone. I think that the reason that there are so few failures during use here is because of this type of testing (and the spinewhack). Every one of us wants to have some reassurance that the lock is going to hold up, so we usually give them a little test.

Like Joe said , our locks should be tested when we get them. It only makes sense. I have seen all sorts of fancy folders fold with just light taps to the spine. This is not just a consideration for defense, but for safety in general. One situation I can see happening is working in confined spaces where the knife has the possibility to hit stuff when moving around (under car dash, in engine compartment) It seems silly, but then again, I have had a knife fold when I tapped it on my knuckles. Having your vorpal sharp folding megaslayer slap shut on you index while under the hood can make for a bad day.

We test everything for reliability, especially for defensive purposes. It would be stupid to go buy a gun and some hot rod ammo for it and then just load it up and start packing it without testing to see if the ammo will feed and shoot straight. I certainly would not want to go into combat with an unfired M16.

With all this testing going on, a certain pattern has developed, and that pattern seems to show that linerlocks tend to fail quite often, followed closely by lockbacks. What is truly disconcerting is that it when it comes to companies producing linerlocks, it does not seem to matter how high up the quality ladder they are, there are still alot of Lemon Linerlocks produced. Lockbacks tend to be lower end items, and it does not surprise me much that they would recieve a little less care in manufacturing, but I think that it should make everyone wary that even a $200 linerlock might not hold up.


It is not a matter of whether or not you are paranoid, it is a matter of whether or not you are paranoid enough.

[This message has been edited by Yekim (edited 14 July 1999).]
Jumbi, you bring up an important point in regards to the validity of the test. There obviously has to be some reason for doing it. You could get any knife to fail if you really wanted to. For example I could take a Sebenza and apply a blowtorch to the blade until the temper was removed and then write up a description of how lousy the edge holding and durability were. It would obviously fail the "blowtorch test".

I don't know why the spine whack test was started but I can easily imagine why for combat related uses you would want the knife not to fold under this test. It is straightforward as the knife might recieve exactly that kind of strike. As for utility folders, while I can't think of a situation where any knife that I would be using would recieve a stress in exactly that manner (unless its something fairly obtuse like something dropping on it), I can think of situations where it will see stresses that are similar in nature. For example I could be digging/prying with the tip and the knife could slip which could result in a sudden torque on the pivot. Or I could slice deeply into something and jerk the folder out.

As with everything else its of little value to test something in a manner that is not important to you so it is very important to know what the reason for doing the test in the first place is. As for the solution, well it would be very straightforward to have a QC guy in place that randomly tests the folders.

The point about damaging the knife through the testing is important. Some of the more stressful tests do wear a knife and why you have to be sensible in applying them. For example if your Axis (or whatever) took a few hard shots from a stick it would probably be time to stop. If you continued beating it you could probably force it to fail. Is this really a failure of the lock or just premature wear? Probably the latter. Then again some locks are supposed to stabilize with wear (rolling lock).

Another thing worth noting is that the spine-whacking test isn't necessarily doing a whole lot of damage. I do all my tests with light to moderate force -- I'm not looking to take chunks out of the table with the blade spine. Typically, these light whacks don't do damage, but they can make the liner wear a little more quickly. But this test actually has an upside -- many times, the spine whack test can seat the liner, so after an initial failure, it never fails again. So the spine whacking test can cause damage if you're really whacking the thing hard, but done moderately causes only a little wear and can even improve your knife!

I saw your post on another thread (about the Gerber folder) and it made me start wondering the same thing. I was going to post something and you beat me to it.
Is the "spine whack" test really necessary?
Is it really indicative of normal knife use (abuse)? When do you plan on using the back of your knife blade as a hammer? A stabbing, twisting test seems more realistic. I could see putting on some pressue to make sure the lock is firm, but I've seen on another thread where someone taped some knives to a baseball bat and then swung them into trees! Ouch! Not gonna do that to my $150 knife.
It's kind of like shooting a derringer at 50 yards to see how it groups.
Maybe it makes more sense on double edge blades too! Take care.

"May you live in interesting times"

AKTI - A000389
IN MY OPINION, I SAY THIS, AFCK, AFCK, AFCK............This in my opinion the most reliable liner lock in the world, more reliable than the military, socom, genesis, and several of my customs, sure some of em are made like crap, but did the lock fail, DID ANYONE'S AFCK FAIL THE SPINE WHACK TEST, if it did, i bet its a very small number. Please read my reply on page 2 of the post "Socom lock failure", on Knife reviews, a very good reply there........

"Am I open-minded, or just Ignorant"....
It's kind of like shooting a derringer at 50 yards to see how it groups.

What knives were being taped to a baseball bat? Is this the next step up to the 'whack' test? The 'McGuire' test?

If somebody is breaking liner locks or lock backs on a regular basis or inducing multiple lock failures it is time to switch to fixed blades. Or consider using a hammer

You and I seem to be of the sme mind about this "whacking" business. My question generated some interesting pro and con discussion that has really been great. But like you, I will probably take it somewhat easy on my gear. However, I think I should give this testing business some thought; I'm sure there's a happy medium in all of this (and my pappy always told me to strike [whack] a happy medium)

There is a lot of experience in this thread that has provided some great counsel; really appreciate the input.