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Strongest, most reliable (and more) folder locks
- Thread starter e_utopia
- Start date
e_utopia,
I can see that not everyone agrees with your summary but thanks for making the effort. Your summary gives good fodder for discussion.
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Hoodoo
Why dost thou whet thy knife so earnestly?
The Merchant of Venice, Act IV. Scene I.
I can see that not everyone agrees with your summary but thanks for making the effort. Your summary gives good fodder for discussion.
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Hoodoo
Why dost thou whet thy knife so earnestly?
The Merchant of Venice, Act IV. Scene I.
I'll take Rob and Spark's comments one level further. A frame lock, such as my BM Pinnacle, can be dowright unreliable in a left hand. A slight torque is applied when you grip a knife. With the right hand, this supports the framelock. With the left hand, the torque is towards opening it up. In a perfect world, no torque would happen and things are safe. In the real world, especially with a strong working knife that is otherwise extremely trustworthy, this very slight turning can easily disengage a framelock. When it does the results are not pretty.
Course most folks are right handed. But what happens when you need to use your left, or weak, hand? I suspect that the chances of an accident are even greater for the right hander that is forced to use his left hand (assuming he hasn't practiced weak hand use). Neither the Axis nor Rolling locks have this UAF (user anoyance feature).
[This message has been edited by Codeman (edited 09-14-2000).]
Course most folks are right handed. But what happens when you need to use your left, or weak, hand? I suspect that the chances of an accident are even greater for the right hander that is forced to use his left hand (assuming he hasn't practiced weak hand use). Neither the Axis nor Rolling locks have this UAF (user anoyance feature).
[This message has been edited by Codeman (edited 09-14-2000).]
e_utopia,
I'm not sure where you got the initial data on the amount of force it requires to cause lock failure, but in the uber-spine whack test that I conducted and posted under Serguisz's review of the pinnacle lock, I found the Axis lock to be more resistant to abuse then the frame lock. I got flamed for posting my test, but in a nutshell, I struck the back of the blades with an axhandle to cause lock failure. You can do a search for it if interested.
FWIW, I still carry the sebenza most of the time. I like its looks and the simplicity of the lock.
I'm not sure where you got the initial data on the amount of force it requires to cause lock failure, but in the uber-spine whack test that I conducted and posted under Serguisz's review of the pinnacle lock, I found the Axis lock to be more resistant to abuse then the frame lock. I got flamed for posting my test, but in a nutshell, I struck the back of the blades with an axhandle to cause lock failure. You can do a search for it if interested.
FWIW, I still carry the sebenza most of the time. I like its looks and the simplicity of the lock.
What would you consider Spyderco's!!!?
I have REKATs and they are awesome, and now I have an AXIS and it too is terrific. But I tell you, I have carried more Spydies over the years, and they have been more then reliable, and not one has ever failed me!
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What we do today in life...echoes in eternity...
Every man dies...not every man lives...
I have REKATs and they are awesome, and now I have an AXIS and it too is terrific. But I tell you, I have carried more Spydies over the years, and they have been more then reliable, and not one has ever failed me!
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What we do today in life...echoes in eternity...
Every man dies...not every man lives...
Eutopia,
I really doubt a frame lock would be stronger than an axis or rolling lock or even some liner locks.
I think you forget to take some things into account. Frame locks are only as strong as their weakest part obviously, and they are usually thinned out to allow the lock bar to bend. This thinning out causes the lock bar at it's thinnest part to be about 1/16" usually. This is in the range of some liner locks. When pressure is applied to the lock and the lock gives way this will be the first thing to go. The 1/16" portion of the bar will bend outwards. A 1/16" thick liner lock will be stronger than a frame lock because a frame lock's lock bar is off center. When pressure is applied the bar wants to bend outwards, and it will. A 1/16" liner lock is more centered and would require more pressure to cause the liner to bend. The scale also helps reinforce the liner.
Gripping a frame lock is a reliability issue and has nothing to do with strength.
Spark:
Frame locks do not purely rely on your grip. It is just that your grip enhances the locks reliability.
I really doubt a frame lock would be stronger than an axis or rolling lock or even some liner locks.
I think you forget to take some things into account. Frame locks are only as strong as their weakest part obviously, and they are usually thinned out to allow the lock bar to bend. This thinning out causes the lock bar at it's thinnest part to be about 1/16" usually. This is in the range of some liner locks. When pressure is applied to the lock and the lock gives way this will be the first thing to go. The 1/16" portion of the bar will bend outwards. A 1/16" thick liner lock will be stronger than a frame lock because a frame lock's lock bar is off center. When pressure is applied the bar wants to bend outwards, and it will. A 1/16" liner lock is more centered and would require more pressure to cause the liner to bend. The scale also helps reinforce the liner.
Gripping a frame lock is a reliability issue and has nothing to do with strength.
Spark:
Frame locks do not purely rely on your grip. It is just that your grip enhances the locks reliability.
Sal Glesser
Moderator
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- 11,665
Interesting thread. thought to throw in some additional opinion.
Reliability is more a function of the manufacturing than type of lock design. A well made anylock can be very reliable. A poorly made anylock will probably not be reliable.
These locks (well made) are going in excess of 100 inch/lbs per inch of blade. I don't think that manual pressure against a lock makes a big difference in lock strength at those numbers.
As mentioned, Frame locks do have their weakest point at the thinned out area which permits bending. this affects ultimate strength. But reliability will be found in the engineering and attention to detail at the interface. Chris Reeeve knives are an example of careful attention to that interface (IMO) making them very reliable.
BTW The new Spyderco Chinook (James Keating design) is a lockback. The lock stregth is exceeding 200 inch/lbs per inch of blade. That is in there with both the Rolling lock and the Axis lock. It's simple, strong, safe, reliable and it's only a lockback.
sal
Reliability is more a function of the manufacturing than type of lock design. A well made anylock can be very reliable. A poorly made anylock will probably not be reliable.
These locks (well made) are going in excess of 100 inch/lbs per inch of blade. I don't think that manual pressure against a lock makes a big difference in lock strength at those numbers.
As mentioned, Frame locks do have their weakest point at the thinned out area which permits bending. this affects ultimate strength. But reliability will be found in the engineering and attention to detail at the interface. Chris Reeeve knives are an example of careful attention to that interface (IMO) making them very reliable.
BTW The new Spyderco Chinook (James Keating design) is a lockback. The lock stregth is exceeding 200 inch/lbs per inch of blade. That is in there with both the Rolling lock and the Axis lock. It's simple, strong, safe, reliable and it's only a lockback.
sal
- Joined
- Feb 7, 2000
- Messages
- 3,221
Okay, I was going to let this thread die, as it seems to be misunderstood, but I guess not.
Hugo, this is looking at theoretical perfect examples of these locks. If not, the strength of the liners, pivot pin and stop pin would tend to play as much of a part in the strength of the lock as would the lock mechanism itself. If, however, you simply want to see and example of knife testing, you might take a look at the link I posted in the other thread (there's a link to that thread at the top of this one). These specific rankings, however, also take into account adjustments to attempt to account for the manufacturing differences between the knives I have actually seen test results for, and the perfect examples this ranking ranks.
Codeman: I'm not following. I can't see where this torque you refer to is applied. Can you elaborate?
Ray: sorry, I haven't read that review. Can you tell me if it was an old-style Pinnacle or hte newer version? The newer one has a re-designed lock which, while easier on the hand, is not as strong. Also, was the handle compressed, as it would be if you hand was holding it? Even a slight bit of hand pressure can significantly strengthen the frame lock.
Glad you got the point that lock strength is only one part of the knife, though. So many others seem to have missed that, and choose based solely upon the lock.
Dangelo, do you mean lockbacks?
JQ: [edit]
Sal: yup, that's why I wanted to look at theoretical perfect examples of each, to eliminate the question of manufacturing standards. Question: do you have any pictures of your lock-testing machine I could see? I have a couple of suggestions, assuming it is as I think it is, based upon the descriptions you and others have posted.
Anyone else who reads this: as I often say, if you need anywhere near the failure strength of any well-made lock, you really need a fixed blade, as any lock could have a micro-fissure (or other flaw) in it which would cause failure at much lower force than would be expected. The lock is a safety device, and a convenience device (blade stays put instead of floppin around), but does not replace a full tang.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-15-2000).]
[This message has been edited by e_utopia (edited 09-18-2000).]
Hugo, this is looking at theoretical perfect examples of these locks. If not, the strength of the liners, pivot pin and stop pin would tend to play as much of a part in the strength of the lock as would the lock mechanism itself. If, however, you simply want to see and example of knife testing, you might take a look at the link I posted in the other thread (there's a link to that thread at the top of this one). These specific rankings, however, also take into account adjustments to attempt to account for the manufacturing differences between the knives I have actually seen test results for, and the perfect examples this ranking ranks.
Codeman: I'm not following. I can't see where this torque you refer to is applied. Can you elaborate?
Ray: sorry, I haven't read that review. Can you tell me if it was an old-style Pinnacle or hte newer version? The newer one has a re-designed lock which, while easier on the hand, is not as strong. Also, was the handle compressed, as it would be if you hand was holding it? Even a slight bit of hand pressure can significantly strengthen the frame lock.
Glad you got the point that lock strength is only one part of the knife, though. So many others seem to have missed that, and choose based solely upon the lock.
Dangelo, do you mean lockbacks?
JQ: [edit]
Sal: yup, that's why I wanted to look at theoretical perfect examples of each, to eliminate the question of manufacturing standards. Question: do you have any pictures of your lock-testing machine I could see? I have a couple of suggestions, assuming it is as I think it is, based upon the descriptions you and others have posted.
Anyone else who reads this: as I often say, if you need anywhere near the failure strength of any well-made lock, you really need a fixed blade, as any lock could have a micro-fissure (or other flaw) in it which would cause failure at much lower force than would be expected. The lock is a safety device, and a convenience device (blade stays put instead of floppin around), but does not replace a full tang.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-15-2000).]
[This message has been edited by e_utopia (edited 09-18-2000).]
E_utopia:
This is false. A properly made liner lock has a blade tang angle which will square perfectly with the liner. When this happens the liner will not slip no matter how much force is applied. Also when force is applied friction is caused and this lessens slippage further.
Which frame lock is this? I'm not sure about the S2 but Benchmade's Pinnacle is thinned out, but you need to look in between the scales to see it. If a frame lock truely was 1/8" then it would be very hard for you to close the knife.
Again, I have to disagree. It does not matter how thick the rest of the frame lock's lock bar is. It's thinnest point is 1/16" and that will be the first to go. Even if the lock bar was 1/4" thick it would still bend at the 1/16" portion of the bar.
The flat part of the liner that is against the scale--you called the scale the liner--is where the liner will want to bend the most, and this place is semi reinforced by the scale which may increase it's strength.
How does it increase the stregnth?
-Johnny
This is false. A properly made liner lock has a blade tang angle which will square perfectly with the liner. When this happens the liner will not slip no matter how much force is applied. Also when force is applied friction is caused and this lessens slippage further.
Which frame lock is this? I'm not sure about the S2 but Benchmade's Pinnacle is thinned out, but you need to look in between the scales to see it. If a frame lock truely was 1/8" then it would be very hard for you to close the knife.
Again, I have to disagree. It does not matter how thick the rest of the frame lock's lock bar is. It's thinnest point is 1/16" and that will be the first to go. Even if the lock bar was 1/4" thick it would still bend at the 1/16" portion of the bar.
The flat part of the liner that is against the scale--you called the scale the liner--is where the liner will want to bend the most, and this place is semi reinforced by the scale which may increase it's strength.
How does it increase the stregnth?
-Johnny
e_utopia - If I grip down hard, as if getting ready to really put some force into a cut, it is very easy for my fingers to push the frame away from my palm - unless the knife is seated all the way into my palm, which doesn't feel nature (Yes, I might just be crazy). When this happens with a right-handed framelock in a left-hand, the framelock is being pressed away from "lockup". If the slightest bit of torque (counterclockwise) is then applied as a result of the cut, it's possible for the lock to be fully disengaged and the knife folds up on your hand. This is easy to accidentally do if you are really pressing into a cut. I had this happen with my BM750 and I ended up with 3 fingers cut all the way to the bone. I've quit using framelocks as a result. The BM750 in question has a solid lockup and fully engages the blade, so it's not a defect problem.
The problem is that when a framelock extrudes enough for the palm to put pressure on the lock itself, a twisting force on the knife in one direction reinforces the lock, the other direction unlocks it. Granted, this twisting isn't likely to happen under most conditions. If you find yourself in an urgent situation where you need do apply some twisting action and a framelock is the only tool available, the twisting had better be clockwise.
Am I making it any clearer?
Sal's probably right about it being more the result of the implementation of a framelock and not a flaw of framelock theory. I just haven't handled one that doesn't have this potential problem. Maybe I'm being too picky - twisting while is cutting doesn't really fall into the normal use category. It does, however, fall into the category of being a real possibility when man's oldest tool is asked to perform outside it's intended function. No matter what tool we might be talking about, the best of the breed can always perform somewhat outside of their intended use, IMO.
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Knowledge without understanding is knowledge wasted.
Understanding without knowledge is a rare gift - but not an impossibility.
For the impossible is always possible through faith. - Bathroom graffiti, gas station, Grey, TN, Dec, 1988
AKTI Member #A000831
[This message has been edited by Codeman (edited 09-15-2000).]
The problem is that when a framelock extrudes enough for the palm to put pressure on the lock itself, a twisting force on the knife in one direction reinforces the lock, the other direction unlocks it. Granted, this twisting isn't likely to happen under most conditions. If you find yourself in an urgent situation where you need do apply some twisting action and a framelock is the only tool available, the twisting had better be clockwise.
Am I making it any clearer?
Sal's probably right about it being more the result of the implementation of a framelock and not a flaw of framelock theory. I just haven't handled one that doesn't have this potential problem. Maybe I'm being too picky - twisting while is cutting doesn't really fall into the normal use category. It does, however, fall into the category of being a real possibility when man's oldest tool is asked to perform outside it's intended function. No matter what tool we might be talking about, the best of the breed can always perform somewhat outside of their intended use, IMO.
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Knowledge without understanding is knowledge wasted.
Understanding without knowledge is a rare gift - but not an impossibility.
For the impossible is always possible through faith. - Bathroom graffiti, gas station, Grey, TN, Dec, 1988
AKTI Member #A000831
[This message has been edited by Codeman (edited 09-15-2000).]
- Joined
- Feb 7, 2000
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JQ: [edit]
Codeman: I still do not see what you are saying. I can concieve of no way in which your left hand applies different pressure to the lock bar than your right. Holding the knife, your thumb should be along the spine, with the center knuckle of your index finger straddling the lock, so that the half of your finger closest to the palm is against the handle, and the half of your finger farthest from the palm is against the lock bar. Your otehr fingers act similarly. There is no torque being applied by the hand in this grip. No torque on the blade should be able to flex the lock bar or frame enough to disengage the lock; this is one of the biggest advantages of the frame lock over the liner lock, as the larger lockup surface is harder to disengage due to torque. Sorry, but I simply cannot understand what you are describing.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
Codeman: I still do not see what you are saying. I can concieve of no way in which your left hand applies different pressure to the lock bar than your right. Holding the knife, your thumb should be along the spine, with the center knuckle of your index finger straddling the lock, so that the half of your finger closest to the palm is against the handle, and the half of your finger farthest from the palm is against the lock bar. Your otehr fingers act similarly. There is no torque being applied by the hand in this grip. No torque on the blade should be able to flex the lock bar or frame enough to disengage the lock; this is one of the biggest advantages of the frame lock over the liner lock, as the larger lockup surface is harder to disengage due to torque. Sorry, but I simply cannot understand what you are describing.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
1)A 1/16" liner would never flex enough to change the angle that it's meeting with the tang. The liner will want to flex outwards and it would have to bend a whole lot before this can happen.
2)Spine wack tests do not use nearly enough force to cause the liner to flex in the way you describe. There can be a host of reasons as to why a liner may slip when a sudden force is applied to the spine of a blade but liner flex is unlikely one of them. Hand pressure would never cause a perfectly made liner lock to fail.
If we are talking about perfect examples of liner locks we will not see lock slippage and all that is left is liner bendage. Besides, I thought we were talking about frame lock strength and liner lock stregnth, not reliability? Slippage is a reliability issue because it usually does not take brute strenght to make the lock slip.
To have a liner shear would mean the liner would physically break off, and that is not going to happen.
When a liner lock fails due to a constant heavy load, the liner will not slip off. It will get bent, the blade will not fall and cut your fingers, but the lock will become useless and the blade will have play.
I agree.
Yes, the amount of force it takes to bend a liner is very great, which is why I think it is mute. Again, with a constant load applied to the spine of the blade slippage will not occur on a properly made liner lock.
Why is a liner lock's angle more acute than a frame lock's? I figure it is less because the liner is closer to the center of the blade and so the angle would be less, whereas the frame lock is centered towards the outside of the handle. This is one of the reasons a liner lock may be stronger, the liner is positioned more closely to the center of the blade.
The thickness is the same as a liner lock.
As I said, a properly made frame lock/liner lock will not slip. This is a reliability issue. If you are He Man and can hold a knife while for some strange reason a lot of force is applied to the back of the blade, the lock bar will bend, your grip has nothing to do with it.
I agree. But almost always, if a lock is reliable, it will only fail if the lock is broken. However these lines can blur, as in a lock back for example.
-Johnny
- Joined
- Feb 7, 2000
- Messages
- 3,221
JQ: [edit]
Art, thanks, at least some seem to appreciate me.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
Art, thanks, at least some seem to appreciate me.
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
- Joined
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db, unfortunately, I have (I also have seen many well-constructed liner-locks which I can not concieve of failing in any reasonable use), but I was lucky enough not to be injured. As for your question, no, the liner would slip outward, not toward the other scale, so the knife would close.
--JB
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e_utopia@hotmail.com
--JB
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e_utopia@hotmail.com
E_Utopia,
First you said the liner or frame would flex, and in doing so would cause the liner or lock bar to no longer match the angle of the blade tang and so would slip off the blade tang causing the lock to fail. Now you say slippage will be caused by the lock face deforming. Since flex is no longer an issue I'll address the lock face deforming.
A properly made liner/frame lock's liner will meet the blade tang perfectly square. It can deform all it want, that will not cause it to slip. A properly made liner/frame lock's liner will be properly hardened and deformation will further be less of an issue. A titanium liner's lock face can be hardened up to 90Rc.
You originally stated a frame lock is much stronger than a liner lock. Now you are talking about them slipping. If this slippage is true, what makes a frame lock stronger?
As for my credentials I have none. I am just a college student that likes knives. Credentials just gives others reason to believe a person if they do not back up what they say. People assume they know what they are talking about. Yet I back up what I say with reason and explanations so I do not see how this is a problem.
This is not beating a dead horse because you brought up new issues and I addressed them, as you did mine.
I'm not trying to attack you or do whatever I can to prove you wrong. I am merely pointing out what I believe to be a mistake.
-Johnny
First you said the liner or frame would flex, and in doing so would cause the liner or lock bar to no longer match the angle of the blade tang and so would slip off the blade tang causing the lock to fail. Now you say slippage will be caused by the lock face deforming. Since flex is no longer an issue I'll address the lock face deforming.
A properly made liner/frame lock's liner will meet the blade tang perfectly square. It can deform all it want, that will not cause it to slip. A properly made liner/frame lock's liner will be properly hardened and deformation will further be less of an issue. A titanium liner's lock face can be hardened up to 90Rc.
You originally stated a frame lock is much stronger than a liner lock. Now you are talking about them slipping. If this slippage is true, what makes a frame lock stronger?
As for my credentials I have none. I am just a college student that likes knives. Credentials just gives others reason to believe a person if they do not back up what they say. People assume they know what they are talking about. Yet I back up what I say with reason and explanations so I do not see how this is a problem.
This is not beating a dead horse because you brought up new issues and I addressed them, as you did mine.
I'm not trying to attack you or do whatever I can to prove you wrong. I am merely pointing out what I believe to be a mistake.
-Johnny
- Joined
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[edit]
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
The points that you mention may have some theoretical value, they are simply not true in real life. Being the aerospace engineer that you are (even though you are still in college and do not even have your BA) you may think you know how a liner lock works but you obviously do not. Put away all those stress analysis classes you have taken and think about it using common sense. A 1/16" liner just will not flex enough to cause slippage in the way you describe. The liner would long take a permanent bend before it slips due to flex.
You do not have to believe me. Just email Sal and ask him what happens to his liner locks when he tests the strength. I'll even go on a limb and say that none of the liner locks he tested had their locks slipped before the liners bent. Or you can try it yourself and see if the locks slip. Simply put the blade of your liner lock into a vice and slowly apply weight to the handle until the liner bends, because that is what will happen. Or you can simply build one of your elaborate machines.
If Sal replies and with his permission feel free to post it here.
-Johnny
[This message has been edited by JoHnYKwSt (edited 09-17-2000).]
You do not have to believe me. Just email Sal and ask him what happens to his liner locks when he tests the strength. I'll even go on a limb and say that none of the liner locks he tested had their locks slipped before the liners bent. Or you can try it yourself and see if the locks slip. Simply put the blade of your liner lock into a vice and slowly apply weight to the handle until the liner bends, because that is what will happen. Or you can simply build one of your elaborate machines.
-Johnny
[This message has been edited by JoHnYKwSt (edited 09-17-2000).]
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[edit]
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]
--JB
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e_utopia@hotmail.com
[This message has been edited by e_utopia (edited 09-18-2000).]