Emerson liner lock vs frame locks strength?

[MrPocketsOfSteel]

I've carried several dozens of Emerson folders over 20 years, and certainly had my share of disagreements about them. But I have NEVER had one have a lock failure under use. In attending knife shows in that same time period, I've never met anyone who personally had one either.

Maybe I'm just lucky that way...

I like the way that was put. Me and some fellas were talking at a Penske shop. It's pretty interesting to hear 'normal' people/ mechanics speak when the subject is knives.

In response to JBravo. I have never personally met anyone who knew of anyone that knew For A Fact and saw the Emerson knife where the linerlock imploded. I'm not saying it hasn't happened in the history of EKI. But it is Very questionable that I can log onto here and read someone's statement about their lock giving out and then two or three more say the same thing. *rolling my eyes

 

[MrPocketsOfSteel]

For most general usage that isn't bordering using a knife in the fashion of a fixed blade or pry tool, the biggest difference between a liner lock and a frame lock is going to be the accessibility aspect, IMHO. I find a good frame lock as generally easier to use, generally less likely to develop "sticky lock", generally easier to detail strip, and generally better-suited to account for usage wear that can sometimes result in blade play or a less-than-great lockup. I do find the frame locks tend to do better with extremely dirty situations.

Many great makers like Emerson have used liner locks for years with great success. Does a test that hangs an anvil on a knife or place extreme force on the back of it in the fashion of hammer represent its capabilities? I don't personally think so. That said, I really prefer the titanium frame Lock's over the liner locks, especially if the liner is SS given titanium alloy's advantages. (IIRC Emerson uses ti liners so not an issue in this specific instance, if so.)

For abuse usage in which someone does not want to get a carbon steel fixed blade, I think the frame lock has advantages to a liner lock, but in perspective both are inferior to a fixed blade with a strong scandi, moran, or flat grind...so usage really can dictate how good or not good something may be...

Good post IMO. I was always of the mind that linerlocks....by their very nature in how they're made - inferior to a framelock. That comes just from what my eyes tell me. Having said that, after talking with an engineer who owns And Actually uses his knives, he explained to me and actually pointed to the parts he was speaking about and it made sense. He lost me a couple of times with his engineer talk but when he got down to my brain level it caused me to rethink the whole thing.

I know what I use my knives for. The normal types of stuff but then again I do like to cut on wood and I really pay attention to what I am cutting/ how much pressure I'm putting on the pivot and edge. How easy or hard the specific edge geometry peels through the wood. These Emersons are the first real linerlocks I have owned with the exception of one cheaper knife and I must say so far so good, I don't see anything out of the ordinary moving or flexing that would give me any concern. It will be very telling say a couple of years from now.....how well especially the Super7 holds up.

 

[pnsxyr]

Good post IMO. I was always of the mind that linerlocks....by their very nature in how they're made - inferior to a framelock. That comes just from what my eyes tell me. Having said that, after talking with an engineer who owns And Actually uses his knives, he explained to me and actually pointed to the parts he was speaking about and it made sense. He lost me a couple of times with his engineer talk but when he got down to my brain level it caused me to rethink the whole thing.

I know what I use my knives for. The normal types of stuff but then again I do like to cut on wood and I really pay attention to what I am cutting/ how much pressure I'm putting on the pivot and edge. How easy or hard the specific edge geometry peels through the wood. These Emersons are the first real linerlocks I have owned with the exception of one cheaper knife and I must say so far so good, I don't see anything out of the ordinary moving or flexing that would give me any concern. It will be very telling say a couple of years from now.....how well especially the Super7 holds up.

Thanks!

I think liner locks in general have gotten a bad reputation due to crappy makers doing poor liner locks that quickly fail. This same thing happened to 440C as crappy makers gave it a notorious reputation and it never really went away.

I also think in terms of the strength discussion that a few aspects that may not often be considered are the stop pin, the pivot, the bearing system, and other joints. Especially with the stop pin, how well the pin distributes loading should depend on how well the pin is integrated with the 'superstructure' (liners or integrated handle) is going to affect most normal usage and the surface area making more over less contact. In this sense, the lock is almost not even used given the force is on the stop pin. Back cuts rarely tend to be forceful on the level of something like batoning or general wood working. In terms of lateral strain, a larger pivot with more surface area to better distribute the load on the larger structure is very important. And like the above, the lock itself is really secondary to other parts that will have to withstand significantly more load. I find this to make cross-comparisons very difficult given the lock strength itself is going to vary based on how well the larger structure is done.






I don't think the cutout on the titanium lock bar on a frame lock versus the full thickness of the liner on a liner lock is really a fair comparison to consider thickness-to-thickness. The thin portion in the frame lock is further towards the back with a thicker portion in the front, and the shock it will have to handle and some of the loading dynamics won't be quite the same as a liner lock if the discussion relates to the area immediately following the lock. If the liner lock is SS and the frame lock is ti alloy, the titanium lock has a huge advantage from materials. Frame lock failures in this regard are rare; in most cases, frame lock failures seem to come from when the lock bar itself is over-extended. With that said, good liner locks also give very consistent performance.

 

[Allex]

Ok, I'll try to explain this ( that, generally speaking, a liner lock will bend easier than a frame lock )
Take a look a the sketch, if I have a pressure on the back of the blade ( like trying to close the open knife ) the main force it's Fr ( which it's parallel with the liner- because the pivot it's perpendicular on the liner and the tang and lockbar have an one point contact, more or less )
Fg force it's parallel with the tang, and it's trying to disengage the lock
Fb force it's perpendicular to the tang and the opposite force ( plus the force generated by the lock spring ) will produse the friction force that will keep the knife open (hopefully).
If the knife remains open, the Fr force it will try to bend the lockbar (on the opposite place, on the spring area, because of the cutout geometry ( short ) we'll have a compression force) . Anyway, if I have 2 lockbars with the same cutout and different thickness, the one that it's thinner will bend first.
And don't forget that for a liner lock, the only force that keep the blade away from your fingers it's the the friction force (Fb' x friction coefficient between the two metals), a drop of water on the tang could be enough for a failure.

 

[ibute21]

Interesting. Learn something new everyday. Time to eat crow.

 

[Lycosa]

Thanks for that, Allex.
rolf

 

[Allex]

You're welcome

 

[Akapennypincher]

I am sure if I purposely tried to destroy a perfectly good product by running it over in slow motion with the Rear Tandems of an 18 Wheeler, it would be destroyed.

But I am more interested in real world failures where any item fails under normal usage.

I have seen demo U-tube of all the wonderful thing you can do with a Cold Steel Knife, but in reality, unless you can personally duplicate the feat of the product being demonstrated.

Would suspect the Cold Steel demo was rigged, or check & casted like when I use to sell cookware at the County Fair.

Part of my demo was burning milk in the frying pan, that showed the ease of clean up, or burn milk. We used half & half, pour out of a Milk container, because half & half burned faster. But milk would do the same thing, but took longer because of a lower fat content in the milk.

Yes the average person could duplicate my Sliver Stone Frying Pan demo. What I did with Sliver Stone Frying Pans, but it would take a few hour of practice.

 

[Aias]

Wild stuff guys; there are times when a lockless slip joint is more than enough... and for me, those times are most of the time. While I love such knives (e.g. GEC's), a one-handed, locking folder is simply more convenient. I expect the lock to work, hold the blade open, etc... but I also know better--placing negative force on the blade (on the spine) or twisting and turning the blade in ways contrary to simple slicing applications increases the risk of lock failure. Sudden and violent stabbing moves (which are hardly the norm for me) also may present lock integrity issues. But a slow, purposeful stabs should be fine, keeping blade pressure moving from edge to spine. Although instances may arise that will put the lock to the test, the Emersons I have seem to have excellent lock-up and no play at all; I am confident they'll hold up under normal usage. For everything else, there are fixed blades, and when possible, I reached for fixed over folding. That said, my cqc super 7 has not left my pocket since I received it; I train in the use of edged weapons (knives included) and would feel confident relying on the super 7 should I have to defend my life. But really, the only thing it is slicing up are packages with nasty attitudes.

 

[cncpro11]

Ok, I'll try to explain this ( that, generally speaking, a liner lock will bend easier than a frame lock )
Take a look a the sketch, if I have a pressure on the back of the blade ( like trying to close the open knife ) the main force it's Fr ( which it's parallel with the liner- because the pivot it's perpendicular on the liner and the tang and lockbar have an one point contact, more or less )
Fg force it's parallel with the tang, and it's trying to disengage the lock
Fb force it's perpendicular to the tang and the opposite force ( plus the force generated by the lock spring ) will produse the friction force that will keep the knife open (hopefully).
If the knife remains open, the Fr force it will try to bend the lockbar (on the opposite place, on the spring area, because of the cutout geometry ( short ) we'll have a compression force) . Anyway, if I have 2 lockbars with the same cutout and different thickness, the one that it's thinner will bend first.
And don't forget that for a liner lock, the only force that keep the blade away from your fingers it's the the friction force (Fb' x friction coefficient between the two metals), a drop of water on the tang could be enough for a failure.

So are you saying that dry frame locks are much better suited for spine whacks? And where are these pictures of bent lock bars?

 

[Allex]

if the cutout has the same thickness as the spring/cutout of the liner lock, same material ( and tang geometry), both will have the same lock strength, but if the lock will not fail, the liner lock will bend easier than the frame lock, if you'll put enough force. But in normal use, you reinforce the lock (I mean a frame lock ) with your hand - more friction force on the contact point and force against disengaging the lock, so you have a much stronger lock than a liner lock.

 

[pnsxyr]

But I am more interested in real world failures where any item fails under normal usage.

My personal take is that when the knife has been engineered well and the user upkeeps it that failure under normal usage is so rare that it is hard to cross-compare locking mechanisms by those types of failures. There are tons of different locks in usage that people use every day with zero issues; so many, that it is hard to even list. In most cases, it seems other components fail long before the lock, and that many of these components are the ones that actually see the heavy stress/strain from heavy (but real-world) work.

I do think that the frame lock has an advantage when the knife itself is absolutely caked with dirt and grime and oil buildup, but I mean absolutely beyond dirty to a point in which most people would not allow a knife to get/stay that level of dirty. Additionally, I think a well-engineered frame lock is one of the best locks for compensating for long-term wear from normal and frequent usage, as evidenced by Sebenzas that are a quarter of a century old and have been used daily, but still lock up like the day it was made. A 25 year old Sebenza may have been opened and closed tens thousands of times or even more, and the design has been able to compensate for normal wear from this repeating process.

In terms of the liner locks used by Emerson, I have zero complaints of functional problems from my own usage, and have found them to perform very well with all types of usage. YMMV.

 

[Akapennypincher]

My personal take is that when the knife has been engineered well and the user upkeeps it that failure under normal usage is so rare that it is hard to cross-compare locking mechanisms by those types of failures. There are tons of different locks in usage that people use every day with zero issues; so many, that it is hard to even list. In most cases, it seems other components fail long before the lock, and that many of these components are the ones that actually see the heavy stress/strain from heavy (but real-world) work.

I do think that the frame lock has an advantage when the knife itself is absolutely caked with dirt and grime and oil buildup, but I mean absolutely beyond dirty to a point in which most people would not allow a knife to get/stay that level of dirty. Additionally, I think a well-engineered frame lock is one of the best locks for compensating for long-term wear from normal and frequent usage, as evidenced by Sebenzas that are a quarter of a century old and have been used daily, but still lock up like the day it was made. A 25 year old Sebenza may have been opened and closed tens thousands of times or even more, and the design has been able to compensate for normal wear from this repeating process.

I find your information very detailed, and good. As they say the world always is on the hunt for a better of any product. build it, market, and if indeed it is better you could be a very rich person.

 

[MrPocketsOfSteel]

Thanks!

I think liner locks in general have gotten a bad reputation due to crappy makers doing poor liner locks that quickly fail. This same thing happened to 440C as crappy makers gave it a notorious reputation and it never really went away.

I also think in terms of the strength discussion that a few aspects that may not often be considered are the stop pin, the pivot, the bearing system, and other joints. Especially with the stop pin, how well the pin distributes loading should depend on how well the pin is integrated with the 'superstructure' (liners or integrated handle) is going to affect most normal usage and the surface area making more over less contact. In this sense, the lock is almost not even used given the force is on the stop pin. Back cuts rarely tend to be forceful on the level of something like batoning or general wood working. In terms of lateral strain, a larger pivot with more surface area to better distribute the load on the larger structure is very important. And like the above, the lock itself is really secondary to other parts that will have to withstand significantly more load. I find this to make cross-comparisons very difficult given the lock strength itself is going to vary based on how well the larger structure is done.






I don't think the cutout on the titanium lock bar on a frame lock versus the full thickness of the liner on a liner lock is really a fair comparison to consider thickness-to-thickness. The thin portion in the frame lock is further towards the back with a thicker portion in the front, and the shock it will have to handle and some of the loading dynamics won't be quite the same as a liner lock if the discussion relates to the area immediately following the lock. If the liner lock is SS and the frame lock is ti alloy, the titanium lock has a huge advantage from materials. Frame lock failures in this regard are rare; in most cases, frame lock failures seem to come from when the lock bar itself is over-extended. With that said, good liner locks also give very consistent performance.

Interesting post. That last paragraph had always been my thought also. Though I have no background in knifemaking nor engineering I had always read the talk about the thin cutout of the Ti framelock to be the part you want to compare in a discussion about strength in comparing to a linerlock.

That just never really held water to what I see and experience. Like you said, often the cutout is so far down there is no way that can be a valid talking point but yet apparently many still feel it is.

Though the lock no doubt is of upmost importance, in most designs the stop pin holds the key to distributing the pressure of the cut. Having said that, I Do wish the pin was a tad bigger in the two knives I have. I don't know if they are the same in every design or not. One fella on YouTube really used the crap out of his CQC7 and ended up replacing his own stop pin......actually a couple times if I remember right. I wished I knew how to do stuff like that or knew someone who would teach me.....I'd really enjoy doing stuff like that at my age now. Ha!