Liner Locks, Thumbs up or Thumbs Down?

I find personally, having large hands, the liner lock is not at all for me. Tightening my grip on the knife will usually unlock the blade! Not something that makes me feel to comfortable as keep all my tools shaving sharp.

Lockbacks used to be the same, but as most are fairly well recessed now, I don't find this to be a problem and the area of my hand in contact with the lockback does not move it as readily as I move the liner lock.

The new styles appear pretty interesting and look like they may be harder to unintentionally disengage. I guess time will tell, but anyway, no more liner locks for me.

The only linerlocks I have are custom, and they will not stand up to heavy lock testing. What set the linerlock up on the road to public success was not its strength, but the fact that you could open and close it with one hand. It become the "worry beads" of the knife community!

Given the position of the cutting edge, the direction of the cut, the tight grips being talked about here, and the fear of blade closing then one should rather be looking to a fixed blade knife.

The guys here talking about their tight grips are obviously worried about the knife twisting in their hand and closing. They should be looking at the handle ergonomics rather than the blade lockup.

Regards, HILTON
Well said, Hilton.

I marvel sometimes at how concerned people get about the strength of a lock when they have no need present or future to use the knife in a way that would break the lock. I own several 3" bladed liner locks that rarely do more than cut packaging. Do I need a rolling lock or integral lock or axis lock to do that? Certainly not. I don't even need a locking folder at all. A Case Trapper will do the job just fine. If the strength of the lock is really the issue then a knife with no lock at all is really the solution. The fixed blade is the way to go.

Lock strength is really more an issue of fashion than utility isn't it?

Knife Outlet

Liner locks are just fine, IMHO. For really rugged use and abuse, I prefer fixed blades. Much safer... and they were designed to be stronger in the first place. Use the right tool for the job and there will be no problems with respect to the tool. Now operator error...
David :

As well I agree, if you want to use a knife hard, use a fixed blade.

Or just buy one with a decent lock. There are locks out there that are easily strong enough and stable enough so that any forces that would cause the lock damage are likely to break the blade before that happens. It is possible to make a lockblade that has more function than a "just in case" senario and is strong enough to use as hard as you want. There is no reason to say "go buy a fixed blade" except as an excuse to not make a lock correctly.

Now if you want to argue that it is important to have the lock very easy to open and close rather than security and strength, well that's cool, different strokes and all that. But the fact remains that stable locks can be built and there are lots of people selling lockbacks that make no warnings about using it hard. Reeves Sebenza for example, or the Mission MPF, or the Axis, or the rolling locks and others.

HiltonP :

The guys here talking about their tight grips are obviously worried about the knife twisting in their hand and closing. They should be looking at the handle ergonomics rather than the blade lockup.

It is not a problem with ergonomics. That aspect becomes an increasing factor when fatigue sets in, but it is a concern even when you are not tired at all. It just depends on what kinds of work you do with your lockbacks.


[This message has been edited by Cliff Stamp (edited 25 June 1999).]
Thumbs up for the liner lock. Les said it long time ago, but it bears repeating: The general public will find the linerlock more than suitable for their needs.

What we have on here, however, are knife fanatics who are not satisfied with locks that are merely adequate for whatever the reason may be. Also, being knife fanatics, we're always fascinated by the latest gadgetry.

That being said, I don't see anything wrong with the lockback either.. when it's done right. And this technology is far more widely available than either the Axis or the Rolling Lock. Cold Steel is a good example of how a company have seen nothing wrong with a good lockback and have stuck with it.

My personal preferences does not represent the views of the public. So what if I don't like linerlocks? They're here to stay.
It would be well to remember that the most popular knife with its most fanatic owners is the Spydie Military, a liner lock. I suspect that the opposition to liner locks is based on the same concern as the opposition to ATS-34. If cheaply and sloppily made, both are problematical, at best. If the ATS-34 is not heat-treated and tempered properly, it is brittle, and if the liner-lock is not properly made, with good materials, it will not work right. Spydie, for example, uses quality materials and does excellent work and their liner lock knives are solid, but I have seen "El Cheapos" that I would not trust to open letters! The liner lock is not a tolerant system. It seems to be either great or awful.

Walk in the Light,
I agree with Les:

(The general public will find the linerlock more than suitable for their needs.)

As the Outdoor Edge warranty states: "This is a quality cutting tool and should be treated as such. Any use of this knife for other than cutting is considered abuse and voids this warranty."

If you want to smash something use a sledge hammer. If you need to pry apart 2x4's use a crow bar.

The only time I really use knives hard is when I'm taking apart deer and elk, and then I'm using a fixed blade.

I am not saying a lock should not be designed as strong as possible, I just think it's dangerous forcing and smashing things with a razor sharp cutting tool. As they say Doo-Doo happens! If you are not cutting, you are much better off with a blunt tool to force, pry and smash with. If you do have a folder that is strong enough to accomplish these tasks you have a strong knife and all the power too you. Just be careful!

Outdoor Edge Cutlery Corp.

David Bloch,

I have a lot of respect for your ability to consume opinions and advice to the ends of assurance of quality on your products. The Magna looks like a good one, and I'm looking forward to getting one. Thanks for respecting us as well.

SB, lockbacks are in general far more stable. They are however more awkward to close. There are also a fair amount of people who believe that liner locks are in general stronger than lockbacks - which I don't think it true. They are definately not more secure.

David, cutting covers a lot of ground as it basically means separate into pieces. I don't smash things up with folding knives or do any chopping with them as they don't have the balance or the weight. I will do assisted chopping with them and may use the butt as a hammer. This depends on the model of course. The Spydero Calypso Jr. is not of much use in this dept. but then again it was not designed for it. Some folders are though - so it can be done.

David and Fred --

You both focussed on lock "strength" in your reply in this string. I just want to point out that every single liner lock complaint, without exception, is based on lack of *reliability*, not strength. I just want to make sure that is crystal clear, there are no strength complaints, the liner lock format is very strong. The strength thing is a non-issue.

For your uses, I agree with you that you probably won't run into liner lock problems often. But there are two things to remember:

1. Not of all us use our folders so lightly. Anyone doing anything beyond very light utility work can end up torquing the blade -- get your knife stuck in cardboard and twist it out for example. Don't scoff about that one, I got email from a guy whose SOCOM gave him a number of stitches due to failure on torquing exactly the way I described. And anyone really using their self-proclaimed "tactical" folders to train will likely see plenty of liner lock failures.

2. If a knife proclaims itself overbuilt, or suitable for heavy use, or "tactical", then like it or not that's the way I'm going to judge it. If you've made an overbuilt folder that really won't stand up to anything beyond "gentleman's" use, then you really have not made an overbuilt folder. And let's be real: put many overbuilt liner lock folders to hard testing, and way too many will fail, in far greater percentages than you'll see strongly-built lockbacks fail. Not a problem if you use your overbuilt folders as gent's folders.

Once again, many of these issues, such as torquing problems, are not ergonomic issues. They are design pitfalls in the liner lock itself, and careful implementation and testing must be done to make sure your liner lock doesn't fall prey to these problems. And this is again one of my problems with the liner lock -- most other lock formats do not have major torquing or spine-pressure issues, at least not to the extent liner locks do. Again, liner locks are easy to build, but difficult to build consistently reliable.

I wish David Bloch luck, and hope he carefully tests his locks rather than dismissing the liner lock complaints as "testing is too tough", "should use a fixed blade instead", etc.


[This message has been edited by Joe Talmadge (edited 25 June 1999).]

[This message has been edited by Joe Talmadge (edited 25 June 1999).]
To Joe T.:

You always offer solid, sensible advice and I agree completely.

In a way I consider you to be the Papa Bear or Merril Lynch of Blade Forums. Shut up everyone! Dad's speaking.

Wishing the best and thanks for the support.

Outdoor Edge Cutlery Corp.

David Bloch,
I would never buy a linerlock. On the cheaper models, the little bit of the lock is uncomfortable to grip. On the more expensive ones, well, it's still a liner lock.
I tried a number of models ranging from a Benchmadeup to a Sebenza, and regardless of the lock quality, I simply didn't find them that easy or comfortable to use. I was holding the Sebenza thinking, ' if only this had a different lock; I'd be interested'.
I'm anxiously awaiting my BM 710. As far as I'm concerned, lock back, or Axis all the way.
Speaking of lockbacks, what's up with that Cold Steel Voyager mid-lock. I loved my old lock-back bucklite. Too bad they changed the design.

My 0.25 cents.
To Chizpuf:

I agree there is nothing wrong with a good old lockback. The only problem from a manufacturers standpoint is lockbacks are out of style.

Styles come and go and I certainly am waiting for the the tried and proven lockback to come back into style.

Outdoor Edge Cutlery Corp.

David Bloch,
"Why Linerlocks are not the best"...By Yek

Linerlocks are inherently danderous by design, and are not as stable as other designs for a plethora of reasons. Most blatantly obvious is the fact that the linerlock does not transfer the closing forces in a straight line to a structural component, but at a slight angle, thus putting some sideways force at the junction between the lock and the tang. This means that the lock relies alot on only spring tension supplied by the leaf, and by friction. which is not reliable because of wear and contaminants.

Another reason that Linerlocks are not the most reliable of locks is because of inevitable inconsistancies of manufacture. I have seen locks from reputable companies fail like a $2 Jaguar, some closing by either hand pressure or even by rpaaing the spine on my knuckles. Life would suck for a companiy to have to hire a guy to spinewhack every knife before it goes out.

One of my personal reasons for disliking linerlocks is because I have found very few that were comfortable. Many knives have the liner protruding a little bit, or have the handle that protrudes a little into where the index groove should be, and that it just annoying. Alot of other knives have a cut out in the handle, and I find that the fleshy part of my index finger rests on the liner which is a discioncerting feeling.I was priveledges to handle a few of my friend's Kit Carson folders (model 4's I think) and they lack finger grooves and protrusions and are made the way a linerlock should be made, and they are still easily (willfully) disengaged when the user wants to close it while minimizing the possibility of accidental disengagement caused by the liner being easily accessed by the fleshy parts of the fingers.

All in all, there are possibilities for new locks, and it seems like, as with everything else, the simpler, the better. Hell, I have a few ideas that I have been kicking around when it comes to lock designs. I am sure that there are others saving for a patent lawyer as well.

Just my thoughts...

Happily flicking my Axis in a catatonic state....


It is not a matter of whether or not you are paranoid, it is a matter of whether or not you are paranoid enough.
Well, I've been digging through my own memory as well as talking to friends who used to work in a knife store and see knives busted up every which way. None of us can ever recall seeing a linerlock "broken" from use.

I'm not talking about closing failures - much good has been said about that very real problem in less-than-well-designed linerlocks. I'm talking about this fear of what Snickersnee calls a floppy little sheet of metal being unable to bear the forces against the blade. This is simply untrue. The linerlock, while thin, is opposing those forces in a way very optimal to its geometry. I have NEVER seen one warp or buckle. The worst I have seen is that they get jammed above the blade; this happens if they travel too far over, and it means the jam open, not close on the user.

I have seen lockbacks break from forces exerted on the blade. The locking bar snaps just behind the tab that fits in the blade notch and the blade is allowed to over-travel like a straight razor. Seen this on some premium knives and plenty of cheap ones.

I disagree with Yekim and others who have questioned linerlock strength. Strength is not the issue! If it is, please produce some account of a linerlock knife (over $10 and not in the context of Spyderco's breaking machine) that has had its liner fold or buckle under stress against the blade spine. I don't think this happens in any reasonable circumstance or we'd have seen one by now.

I have seen a BM CQC-7 that had been run over by an armored vehicle... that was definitely "broken" but I don't think it should count


(Why else would a bear want a pocket?)
The liner lock while a good basic lock cannot even compare to the Rolling Lock in terms of strength and wear. The Axis lock and rhe Rolling Lock while new to the market will eventualy get a greater acceptance.
There will be a few other manfactures making the Rolling Lock in the near future it is as ecominical to make as a liner lock and has a longer life span as it wears in not out and smokes any liner lock in terms of strength. Will it make the liner lock disapear, I doubt that, there are more slipjoint (non locking) knifes made than all the locks combined.

Bob Taylor

Some days it's not worth chewing through the restraints and escaping.

I am not saying that the lock would fail from breakage, but that it fails because the lock wants to slip out from engagement. Because of the angles, the liner tends to be forced in the direction of unlocking, not towards the opposite side. I know a linerlock can be made strong, and I have seen bum lockbacks too. To me it is like trying to stack blocks that are not perfectly square. It just don't werk.

As for those who think that if you need a tough knife, you have should carry a FB, I have to disagree. Life has a tendency to put us in situations where, despite our best efforts, we are ill prepared. I cannot always have a 4" fixed blade on me. Expediant field repairs often catch me unprepared and away from the proper tooling for the job. I always have a folder on me, and sometimes I have to use it for things that stress it well beyond what a knife was intended for. It is comforting to know that it will not let you down when you need it most. Whether for defense, or just a "security blanket" having confidence in something when the chips are down sometimes makes the difference between life and death.

Not everyone can pack a sharpened prybar to work, or around town. A folder with a reliable lock on it is often our only choice. Though I have some well executed linerlocks, as a whole I have lost faith in the design. Each one has to be inspected before purchase to account for manufacturing defects or inconsistancies. That alone is something you really do not have to worry about with the Axis and Rolling locks, or even lockbacks for the most part. IT is like the old Chevy 5.7 liter diesel, I am sure there were a few that ran forever, but as a whole, they were lemons.

This is an interesting thread for me. As a design engineer with 25 years experience, I have learned to look at most mechanisms from both a "failure mode assessment" standpoint (what might go wrong and what happens when it does); and a "manufacturability assessment" standpoint (how easily made, how does the mechanism match the production methods available). I should also say that I'm presently learning to make knives. After I've got a half dozen or so fixed blades under my belt, I'll be designing and making a folder, most likely a liner lock.

I've purchased two "good, but relatively inexpensive" lockbacks (Spyderco & SOG) and one "good but mass produced" liner lock (Benchmade Crawford Leopard) to examine. I've also looked at as many folders in all classes as I could get my hands on. I'll state the following only as my observations (not to be confused with with the knowledge that comes from long experience):

Lockbacks have several parts which would be relatively difficult to make one at a time. These same parts are easily made in quantity however, and don't have too many tight tolerances. (Good for mass production, bad for custom makers.)

Lockbacks are relatively insensitive to loose/tight blades, particularly important for the twisting failure mentioned earlier. This is at lest partly because of the way they engage the blade.

Liner locks are easily created out of parts that knives have to have anyway (the blade and a liner or frame). There are several interacting dimensions which are critical enough to require either very tight tolerances or hand fitting. The fitting of the blade to lock "should" be relatively easy for a custom maker, but a real money pit for the mass producer.

There are a lot of liner locks which are either poorly designed or poorly fitted, even before you get to the question of access to the release. In some cases I've seen different examples of the same knife behave very differently.

Some liner locks don't like loose blades. Some people like to loosen the blade pivot so that the blade can be flicked out easily. Unfortunately...

Most liner locks don't like the blade to be flicked. (I don't blame them.) Look where the liner meets the blade with a normal opening vs. flicking it open. Over time this has got to be a real reliability problem.

Most liner locks are not "engineered". I'm not trying to be critical here. The people I've talked to have solid mechanical aptitude and have learned what works "the hard way". The problem is that it's got to be difficult to know how close you are to not working. Even with today's engineering tools it's not easy to analyze. What you have is a simple mechanism with very complex interactions, particularly taking into account tolerance and wear.

I'm going to try a liner lock when I get to that point, mostly because I want to look into the engineering; and because I can more easily make the parts one at a time.

Thanks for your patience. Sorry if the post got carried away (this is only my second), but it's nice to get excited about engineering agin.