Frame lock compared to back lock

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maximus83

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Nov 7, 2011
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In popular production knives, what are the pros and cons of a well executed frame lock versus a well executed back lock? For instance: compare a Zero Tolerance 0560/0561/0562 frame lock, to back locks such as those you see on Spyderco knives (like the the Native 5, one version of the Manix, the Chinook) or a Cold Steel Triad lock.

Is one more likely to fail under heavy lateral stress?
Is one more likely to fail under heavy vertical stress?
Is one more likely to wear out under regular usage?
Is one more likely to fail if you get dirt in the mechanism?
Is one lock type overall likely to be stronger/safer than the other?
 
The frame lock is stronger and easier to maintain. But, neither knife should fail if you use it correctly, because you should never use a knife in a manner that loads heavy stress on a mechanical latch. For that kind of work, you should be using an appropriate fixed blade.

n2s
 
If these questions really matter than you need to start using your knives properly or get a fixed blade.
When using a folder properly in most situations ( processing game may be a different story ) the blade is pushed into the open direction and doesn't really need to lock.

One may be stronger than the other, but if people would learn not to rely on them they wouldn't have to get so hung up on what's the latest and greatest locking mechanism and just pick knives they like based on other aspects.

I don't think you should focus which is supposedly stronger, but which one you prefer the operation of.
 
Hickory n steel said:
If these questions really matter than you need to start using your knives properly or get a fixed blade.
When using a folder properly in most situations ( processing game may be a different story ) the blade is pushed into the open direction and doesn't really need to lock.

One may be stronger than the other, but if people would learn not to rely on them they wouldn't have to get so hung up on what's the latest and greatest locking mechanism and just pick knives they like based on other aspects.
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Condescending BS. I know how to use a folder (very little, in my case, I'm going almost entirely fixed). Still interested in the discussion of the relative merits of different locking systems, and last time I checked, this is a knife forum. Thanks for nothing.
 
Blade HQ, and some others have tests on UTube.
IMHO Frame locks are the most reliable.


As you will see... the tests are pretty sketchy at best.
 
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To some small degree I agree.

However it is the scalloped out area of the frame that fails on frame locks under stress. Not so much a slippage of the frame outwards.

I prefer them mainly because they are less prone to failure due to debris in the mechanism. the blade itself both prevents debris large enough from getting in, and the wiping action of opening the blade will clear most small debris.
Just my opinion.
 
maximus83 said:
Condescending BS. I know how to use a folder (very little, in my case, I'm going almost entirely fixed). Still interested in the discussion of the relative merits of different locking systems, and last time I checked, this is a knife forum. Thanks for nothing.
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Im sorry if I offended you or something, I guess I just wasn't very clear.
I wasn't saying that strength completely doesn't matter.
What I was saying is that if an important knife buying decision was based around lock types you shouldn't let supposed strength keep you from buying a knife you like.
In most normal use a knife is forced against the back spacer, lock bar, stop pin...ect so you shouldn't be in danger of one folding on you unless using your knife in an unsafe manner.

Now as far as strength goes, I have more confidence in a lock bar than a stop pin to well stop my blade.
Not to say that lock bars fail all of the time but they are much smaller than a much larger lockbar.
Tests normally seem to test how well a lock holds a blade open which may be their job, but what they need to test is how much Force it takes for a knife to fold backwards which is the direction a blade is forced during normal use.
I may be wrong, but I think a stop pin might fail before a back lockbar in most cases.
 
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I would be very grateful to have a sharp blade fail backwards vs failing closed.

My only concern in using folders is a failure rendering me with a few less digits, and I've broken a lot of folders. (still have the digits tho)
 
Zombie411 said:
I would be very grateful to have a sharp blade fail backwards vs failing closed.

My only concern in using folders is a failure rendering me with a few less digits, and I've broken a lot of folders. (still have the digits tho)
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You would probably come away with much less harm if any at all, but how when just cutting stuff normally will a non garbage knife close on you.
I am simply asking because I've never had even a slipjoint with weak springs close on me.
I could see an issue when trying to penetrate thick materials, but I always hold the blade near the tip when piercing thick things because I don't want to stab myself if the blade slips.

Am I not right in thinking that the most Force is exerted in the opened direction ?
 
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Charlie Mike said:
The biggest strength of the framelock is your grip reinforces the lock.
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I wonder how true that is. Atleast for the way I grip the knife the lockbar site more in the crook of my fingers in my left or right hand. I seriously have wondered for a long time if the force I put on a lockbar while gripping my knife normally would be enough to stop the lock from failing. consider that the force would have had to be enough to cause that lock to fail in the first place. Also under normal use I am not gorilla gripping my knife or holding it in such a way as to maximize the pressure applied to the lockbar. Obviously every hand and every knife is different.

Is a framelock stronger than a backlock? Depends on the knife but I always thought a backlock was stronger. That's assuming the framelock is properly built which frame/linerlocks seem to get more problems. I have heard people of the opinion that linerlocks are safer than framelocks due to them bowing against the opposite liner and jamming the blade open. Atleast that's what they say they're supposed to do. If you look at the relief cut on most framelocks it is not much thicker than a linerlock.
 
Charlie Mike said:
The biggest strength of the framelock is your grip reinforces the lock.
Click to expand...

This is accurate. Simply stating "frame locks are stronger" is inaccurate. Many people fail to realize friction is the main holding force of a framelock, not the bar itself.

In my opinion framelocks are like duct taping mirrors to a sports car. Sure it works, but there is too much performance variation to deserve a place on a precision machine. Just my opinion, but I know a master knifemaker who also dislikes frame locks, so there is a basis.

Without reinforcement, backlocks are stronger by far. But it only takes a relatively mild grip to increase the frame lock strength by a significant margin.

Let's be realistic though: unless you plan to use your knives as icepicks in the reverse direction, you'll be fine. Framelocks win for ease of use, so I would recommend it on that basis.
 
Cutlover said:
This is accurate. Simply stating "frame locks are stronger" is inaccurate. Many people fail to realize friction is the main holding force of a framelock, not the bar itself.

In my opinion framelocks are like duct taping mirrors to a sports car. Sure it works, but there is too much performance variation to deserve a place on a precision machine. Just my opinion, but I know a master knifemaker who also dislikes frame locks, so there is a basis.

Without reinforcement, backlocks are stronger by far. But it only takes a relatively mild grip to increase the frame lock strength by a significant margin.

Let's be realistic though: unless you plan to use your knives as icepicks in the reverse direction, you'll be fine. Framelocks win for ease of use, so I would recommend it on that basis.
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That is exactly how I plan on using my knives actually.
 
Look, there must be a valid reason why cold steel
went back to its version of the lock back
(Namely the triad lock).
Figure, over the years,
the liner lock has had its share of every knock imaginable
From just about every knife reviewing you-tuber.
Especially one concerning locking failures due to spine whacking test
which in most cases, would cause enough shock to disengaging the contact area
Of both the vibrating blade and "locked" liner.
The one great thing that liner lock system have,
Is that unlike the back spring lock system which creates resistance,
the blade on a liner lock pivots freely as adjusted by the friction on its pivot screws
Thus Allowing for a looser or faster blade opening.
The beefier frame locks may offer some ability to take on more stress
In so far as undue or excessive force, leading to the liner bar bending or deforming.
There are three stress points in a liner lock system.
This would be the pivot, the locking bar and back stop pin.
A folding knife would become undone if the materials in any one of these
Points fail to take on an applied amount of stress beyond its inherent capability.
Lateral stress is something concerning the pivot and pins holding the handle together.
Again, if the materials of these parts are soft or brittle the threads would fracture or disintegrate.
I would be more concerned of the technical specifications found on these threaded parts
Far more than anything else.
 
I think liner springs and frame springs are prevalent because they are cheaper and easier to mass produce. They aren't the best locks.

Hand pressure doesn't help much with frame springs. This is because the fleshy, soft part of your finger is what is pressing on the frame spring. The soft, easily compressed pads of your fingers don't really provide as much pressure/resistance as you might think.

This doesn't mean frame or liner sprung knives are low quality; there is much more to a knife than the lock (ergonomics and edge geometry are arguably more important).
 
Strength isn't the only factor. Backlocks posses a strong bias towards closing that frame locks do not have. I appreciate that myself. Frame locks are less sensitive to dirt and more often pocket lint. I have had pocket lint build up over time in a backlock. It is easy enough to clean out but also easy to not notice.

I personally prefer backlocks.
 
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