Liner locks: Pros and cons

Barry H

Barry H

Joined
Nov 3, 1999
Messages
1,679
I am curious what the rank and file believe to be the strengths and weaknesses of liner locks. I would also like to know how the major manufacturers rank in their use of this lock. Thanks for all input.
Barry H
 
I personally like liner-locks for their ease of one-handed opening and closing; especially their closing. I find the new locks, like Axis/rolling, require a bit more effort to close with one hand.

I also believe that a well made liner-lock is fairly safe from accidental closures.

What do I NOT like about liner-locks? Only the poorly made ones, and those with thin liners.
 
BTTT....
Any other comments? I have had two knives from reputable companies, fail due to liner lock failure. I was hoping to get some more feedback.
Barry H
 
I have spine whacked all of my liner locks and can not get one to fail that way. And this includes 6 BM's, 3 CRKT's, and even half a dozen $5 knockoffs (which I don't carry). I have no problems with a well made liner lock. There is a possibility of accidentally disengaging, and I can do it on purpose with all of them, but not in a natural grip or one I would ever use for any other purpose than trying to make the lock fail. When I use a liner lock, I make sure I'm not holding it in a way that facilitates this failure, like I do with any kind of folding knife. So yes, I like them, I trust them, and I use them. Though I do like the Axis lock better.

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Jason aka medusaoblongata
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"I have often laughed at the weaklings who call themselves kind because they have no claws"

- Zarathustra
 
I love liner locks, I have never cut myself while closing these knives, I have however come close though. I've used my BM Setinel almost daily for three years and the liner lock has never weekened.

I don't think you will have a problem with any of the major companies. I have heard reports of bad lock up with some BM's, after 3 of thier liner locks. I have never had this problem. But it is a good idea to inspect any knife before you buy it. MT's BM's Spyderco's all have excellent liner locks in my opinion. Periodically check your knives for bad lock up, needless of who makes them.

You should check out the axis locks though. I my self find my 730 to be as easy to flick open as it is to flick it closed. I also feel that this is one of the strongest lock up mechanisms on the market.
 
I think the key issue here is 'good fit' from a quality company. I've never had one problem, and 3/4's of my knives use liner locks. My Emerson Commander locked up so tight, it was a pain to close, but then, that knife is built more for strength than for precise cutting.--OKG
 
I've cut myself before while closing the liner lock. Removed alot of skin off the tip of my thumb (no permanent damage except it feels a little numb at the very tip). Closed it quickly and didn't get my finger out of the way.

Anyways, I'm a little more careful now. I normally don't have any problems with liner locks. I've seen some that will unlock by lightly tapping on my knee though. I don't trust those.

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Chang and the Rebels of the East
(Southern Taiwan Shall Rise Again!)
taiwan.gif
 
I personaly prefer lockbacks. As I understand the lockbacks most common failure is that little pivot pin that locks the whole mechanism. Although lockbacks are not that sensitive to dirt, too much dirt or pocket lint will prevent the lock from fully engaging.

However as I said, I still prefer lockbacks.

Here is why: A liner locks weakest point is the blade pivot itself. After some frequent usage it may just brake. Further on, failures in a liner locking mechanism often depend on the small tolerances in the locking mechanism. In order to avoid a failure, the knife requires some carefulness in order to avoid too much dirt, lint and also liquids interfeering with the locking mechanism.

Also, after years (sometimes shorter) of usage, the spring will get softer and this may result in an unpropper engagement of the blade resulting in a misfold. Watch out for this!
 
I think that most major manufacturers have solved their liner lock problems. You can still get one that sucks, but it is less likely than just a year ago. I trust my Spyderco Military, Terzuola ATCF, Microtech LCC M/A and CRKT KFF implicitly. None have shown signs of loosening or major wear and lock-up rock solid. I am very tough on locks too (ask Senator). One thing that is a requirement when purchasing a liner lock is to inspect it before you buy it. Axis and Rolling locks don't really need this, but the knives they are employed on usually have other problems that DO need inspection. I can safely recommend the Microtech LCC and the Spyderco Military as liner locks that probably don't need to be inspected. They are pretty consistent in quality. YMMV.

Later,
Chris
 
I've had knives with liner locks that didn't fail, but made me nervous because of the position of the liner lock on the blade.

Overall, I like them, because they are easy and convenient to use.

I have cut myself a few times and shave the top of my thumb all the time as Commrade Chang mentioned. But that was always due to carelessness.

Personally, I prefer integral locks like on my CR Sebenza and my Elishewitz Diablo.
 
Barry,
It sounds as if you've already had some good experience in terms of getting to know which brands not to buy.
smile.gif
Rather than cast aspersions on the hit or miss liner lock QC efforts of some major manufacturers, how about I just say that I can highly recommend the liner lock folders that are produced by Microtech. Only once have I had one of their knives that didn't give me a rock solid liner engagement on the first half of the blade tang. In that one instance, the blade locked up tightly, but did so slightly beyond the halfway point. I called MT and they immediately agreed that this shouldn't be the case. I sent the folder back to them and they had it repaired free of charge and returned to me in under a week. For my money that sure beats having to listen to some other company try and convince me that a liner that goes all the way across the tang isn't really a problem.

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Semper Fi

-Bill
 
liner lock likes:

- very smooth action because no spring action on blade

- doesn't require knifemaker to have sophisticated tools to make

- plenty strong

liner lock dislike:

- can spring open in pocket, due to lack of spring acting on blade, and the fact that the ball bearing detent is so difficult to get just right

- right- or left-handed, not ambidextrous

- Often unreliable due to extreme difficulty in doing consistently right. I know many people thing only the bad-quality liner locks have reliability problems, but this is basically a tautology. If you define any unreliable liner lock as having bad-quality, then you end up dismissing the real problems. The fact is, even among the best liner lock makers and manufacturers, there's a surprisingly high number of unreliable liner locks. And it gets worse from there. The conclusion I draw from this is that the liner lock format is so difficult to get right, that even high-quality makers have problems with it. There are also too many problems it's susceptible to: white knuckling, continuous or impact force on the spine, torquing, or any combination of the above.

That said, there are definitely makers and manufacturers who are much better than other when it comes to their liner locks. But if you're talking about the liner lock format as a whole, it is not as reliable as even a lockback, in my experience.

Joe
 
 
I have also had several liner locks from reputable companies fail. The most common failure was that when i squeezed the handle in a firm grip during heavy cutting, on some occasions, the liner would unlock duw to the inward pressureon the lock and angle of the bevel on the liner. (I hope I described that correctly. That is why I like the liner lock to be somewhat recessed. One of the best examples of the recessed liner is PC's KFF.

The single best Pro for the liner lock of course is the ease of one hand opening and closing. it is fairly easy to manipulate the knife in the hand to engage and disengage the knife.

As already mentioned though, a con would be that your thumb that is doing th unlocking can be potentially cut whiel closing the knife.

Sp bottom line? Get a liner lock with a recessed liner.................or get a Rolling Lock, Button Lock, Axis, etc...
 
Thanks very much for all the feedback. I especially learned lots after reading Joe's post. Right now, I am about ready to sent back a Spy. Military for inspection of the lock. I have only had this blade less than 4 months and there is a lot of play in the blade when its locked. This didn't happen over night, however. I just noticed the problem yesterday: If I hold the blade in my left hand and the handle in my right and try to close the blade without disingaging the lock, I can see and feel the lock move away from the inside of the blade, almost to the point of disengagement. I really don't like this scenario. Seems to unsafe for me. What suprises me the most is that it's a Sypderco. I have every intent on giving Spyderco an opportunity to correct this problem--I have too many other Spydies. I think they produce a great product> So I guess I learned more than I wanted to know about liner locks. I must have gotten one that falls into Joe"s "dislikes" category!
Thanks again.
Barry H
 
In my opinion, the strength of the liner lock, as far as the custom knife world is concerned, is that it is easy to manufacture by hand. Sure, they take some expertise to make work well, but the tools and technology needed to cut a lock bar out of a Ti liner are quite simple. You can even have your liners laser or water jet cut for you.

Another strength is that they are quite strong if they hold, especially if they are cut from fairly thick stock.

The primary weakness of the liner lock, is that even when made to perfection, it relies on friction between the lock bar end and the blade tang to keep it in place. Wear, dirt, over lubrication, under lubrication, handle torqueing, and a lot of other variables can reduce that friction to the point where a sharp impact to the blade spine, or even hand closing pressure, will cause it to release. I have experienced this with liner lock folders made by the acknowledged best makers. It is not the fault of the makers, it is the fault of the mechanism.

The liner lock is old tech. The integral side lock, the Lake/Walker LAWKS system, the Axis lock, the Rolling Lock, the SpeedTech button lock, the Spyderco Compression lock, the Sawby lock, and various button locks all make it obsolete for hard use cutting tools. It is just fine for fancy folding pocket knives though. Just keep in mind that "folding" is the key word.

[This message has been edited by Steve Harvey (edited 11-08-2000).]
 
Pro: easier to close one handed, smoother on average than a lockback.

Con: May catch on gloves while heavy cutting or may be engaged while heavy cutting.
 
I do not think most folders are suited to 'heavy usage', I switch to fixed blades.

That being said, I think that the main advantage of liner locks is the 'one hand' closing. Even this advantage becomes a liability if the detent is not correctly done. I have one BM that likes to open at the slightest nudge.

I think that lockbacks are more susceptible to dirt and are harder to keep clean.

All in all, I prefer linerlocks over lockbacks. (And framelocks over either!)

Steve-O
 
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