hi Dew, this location http://www.equipped.com has a break away motion picture of an Axis lock go to his knife section. Akabu
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Which is stronger: REKAT roller lock vs. liner locks vs. Axis lock?
- Thread starter Broken Arrow
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hi Dew, this location http://www.equipped.com has a break away motion picture of an Axis lock go to his knife section. Akabu
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Dew, I did not say that only scientists and engineers are qualified to test knives. I said that Cliff uses scientific and engineering language to hide his failings, and that the average person cannot tel that he is faking it. Re-read my post, please.
--JB
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e_utopia@hotmail.com
--JB
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e_utopia@hotmail.com
Akabu. Thanks for the link.
JB. OK. If we can't avoid being pedantic, why don't you use your engineeering knowledge to rigorously analyze it, say, do FEAs for both rolling-lock and axis locks, and show us why rolling locks are weaker? If that comes out as a good analysis, it would then be helpful for REKAT to improve their products.
I hardly imagine how a rolling-lock would fail a spine-whack test. In fact, I once saw some nice pictures form a forumite's website where he attached a Carnivour to a steel pipe and whacked it hard and the knife survived.It could happen that the tested knife in above URL you gave could be defective in some way.(I still don't understand why the tester you mentioned won't allow Bob Tayler to examine the knife ? )
Also, good net etiquette is we never shoot at the messenger. We argue based on the contents , using facts, figures, or data, and whather that helps support our thesis. Accurate or not, the readers decide. That is what Cliff has been doing and I admire him.
Dew.
[This message has been edited by Dew (edited 08-28-2000).]
JB. OK. If we can't avoid being pedantic, why don't you use your engineeering knowledge to rigorously analyze it, say, do FEAs for both rolling-lock and axis locks, and show us why rolling locks are weaker? If that comes out as a good analysis, it would then be helpful for REKAT to improve their products.
I hardly imagine how a rolling-lock would fail a spine-whack test. In fact, I once saw some nice pictures form a forumite's website where he attached a Carnivour to a steel pipe and whacked it hard and the knife survived.It could happen that the tested knife in above URL you gave could be defective in some way.(I still don't understand why the tester you mentioned won't allow Bob Tayler to examine the knife ? )
Also, good net etiquette is we never shoot at the messenger. We argue based on the contents , using facts, figures, or data, and whather that helps support our thesis. Accurate or not, the readers decide. That is what Cliff has been doing and I admire him.
Dew.
[This message has been edited by Dew (edited 08-28-2000).]
dogboye
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Dew, I don't have a rolling lock or a frame lock, but I do have an axis lock. Bottom line is, I would trust my life to sticking the blade into something and putting all my weight on the lock. I would NOT trust the blade, though. After destroying one 710, using my weight, a hammer, and various other abuses, the blade was trashed, but the lock and the pivot pin held.
I would imagine the rolling lock would do the same or similar. When you get into the realm of the rolling, axis, arc, and frame locks, lock "strength" is not the major concern, IMO. Lock "reliability" is. But, any of them will break your hand before the lock lets go.
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iktomi
I would imagine the rolling lock would do the same or similar. When you get into the realm of the rolling, axis, arc, and frame locks, lock "strength" is not the major concern, IMO. Lock "reliability" is. But, any of them will break your hand before the lock lets go.
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iktomi
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Me neither. But I vaguely recall someone (Steve Harvey?) seeing exactly that once. I don't remember the whole story, maybe Steve will come by and elaborate yet again for us. I think it was a QA problem that's fixed. Always worth testing though, for exactly this reason.
Regarding Cliff, I've read his arguments, and the arguments of many of his critics (e_utopia, etc.) very carefully, and as objectively as possible. I come out of this still greatly admiring Cliff's work in this area, and they remain some of my fave posts on bladeforums. I don't see the "my stuff is scientific, everyone else's is not" bias he's supposed to have. I do sometimes see a difference between what users report in real life, and the outcome of Cliff's tests. That doesn't invalidate Cliff's tests, but means that differently-designed tests may be of interest in addition to the tests that were already done.
Joe
[This message has been edited by Joe Talmadge (edited 08-28-2000).]
not2sharp
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I am also glad to see Cliff raising some of these issues. knives are relatively simple tool, but the process of using a knife is complexed, and the results are very subjective. I can always count on Cliff to raise a number of concerns, many are which are relevant to my own experiences.
The first step in understanding a problem is to table all potential issues. Cliff is doing a good service in this respect.
The first step in understanding a problem is to table all potential issues. Cliff is doing a good service in this respect.
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Ok, Dew, let's look at this as pure engineering, okay? If you really want the FEA done (Finite Element Analysis, a method of simulating engineering structures, for the rest of you, since I refuse to hide behind a language barrier), you can do them yourself; I don't have the time at the moment.
The engineering itself is rather simple, and it makes me doubt the program over at UMA that you can't seem to do it yourself. Both locks are based on putting a pin in quadruple-shear.
The Axis lock uses a cylidrical pin, moved into and out of place by a sliding motion. The Rolling lock uses a semi-cylidrical pin (REKAT's website has a drawing), rotated to either stop the tang, or allow it to pass.
The Axis lock places the entire pin in shear. The Rolling lock places the entire pin in double-shear, and the part where the tang contacts the pin in an additional double-shear. However, since the Rolling lock must use a cam action to account for wear, the area which the tang places in double-shear is, by definition, smaller than the whole pin (and, in practice, must be smaller by a good margin to allow significant amouts of wear to be accounted for). This is an inherently weaker design, as any engineer should know.
As to why the post-tested knife intemittently failed the notorious 'spine-whack' test, this is also a bit of simple engineering. As the tester stated, the pivot pin was bent significantly, and the lock pin was dented significantly. While the pivot pin may or may not be the result of an isolated manufacturing defect, the lock pin comes as no surprise. The Axis pin is a complete cylinder, the Rolling lock pin is a partial cylinder; an inherently weaker structure. The cumulative play of both the bent pivot pin and the dented lock pin add up to enough play to allow the blade tang to pass the lock pin on occasion, when both are flexed slightly more due to the impact force. The intermittent nature of the failure might be due to slightly different amounts of impact energy on different tests (humans can't maintain rigorous force controls, despite Cliff's statements to the contrary), or it might be that the lock was still engaging when it was at the full extreme of it's wear-adjustment cam cycle, but the mechanism of the lock was damaged and did not always hold the lock in that position. I would need to observe it more closely before I would hazard a more definitive answer.
Re Cliff: I'm not shooting the messenger. If you read my posts in the Talonite thread, you will see me say that I think his tests are valid as real-world tests. I question his right to call them science, which they are quite clearly not. I would be happy to go and get some examples if I had the time, but he has made a lot of posts, and it would take a while to sort through and find examples which would still make sense out-of-context. Make no mistake, Cliff is quite the master of verbal trickery, taking care that he nearly never says outright what he obviously implies so often.
rockspyder, thank you for bringing up reliability. This is another reason I strongly favor the Axis lock. Aside from the frame lock, the Axis lock is the most resistant to failure due contamination, and the Axis is more wear-resistant than the frame lock (thought that margin is quite small for a well-made frame lock).
How's that, y'all? I hope I was able to keep the wording on a fairly readable level, although Dew's request made some engineering terminology unavoidable. If anyone would like further explanations of any of the terms, perhaps emailing me would be a good idea; I could then post all the explanations at once (assuming any requests are actually made), rather than crowding this thread with fifty more posts explaining terminology.
--JB
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e_utopia@hotmail.com
The engineering itself is rather simple, and it makes me doubt the program over at UMA that you can't seem to do it yourself. Both locks are based on putting a pin in quadruple-shear.
The Axis lock uses a cylidrical pin, moved into and out of place by a sliding motion. The Rolling lock uses a semi-cylidrical pin (REKAT's website has a drawing), rotated to either stop the tang, or allow it to pass.
The Axis lock places the entire pin in shear. The Rolling lock places the entire pin in double-shear, and the part where the tang contacts the pin in an additional double-shear. However, since the Rolling lock must use a cam action to account for wear, the area which the tang places in double-shear is, by definition, smaller than the whole pin (and, in practice, must be smaller by a good margin to allow significant amouts of wear to be accounted for). This is an inherently weaker design, as any engineer should know.
As to why the post-tested knife intemittently failed the notorious 'spine-whack' test, this is also a bit of simple engineering. As the tester stated, the pivot pin was bent significantly, and the lock pin was dented significantly. While the pivot pin may or may not be the result of an isolated manufacturing defect, the lock pin comes as no surprise. The Axis pin is a complete cylinder, the Rolling lock pin is a partial cylinder; an inherently weaker structure. The cumulative play of both the bent pivot pin and the dented lock pin add up to enough play to allow the blade tang to pass the lock pin on occasion, when both are flexed slightly more due to the impact force. The intermittent nature of the failure might be due to slightly different amounts of impact energy on different tests (humans can't maintain rigorous force controls, despite Cliff's statements to the contrary), or it might be that the lock was still engaging when it was at the full extreme of it's wear-adjustment cam cycle, but the mechanism of the lock was damaged and did not always hold the lock in that position. I would need to observe it more closely before I would hazard a more definitive answer.
Re Cliff: I'm not shooting the messenger. If you read my posts in the Talonite thread, you will see me say that I think his tests are valid as real-world tests. I question his right to call them science, which they are quite clearly not. I would be happy to go and get some examples if I had the time, but he has made a lot of posts, and it would take a while to sort through and find examples which would still make sense out-of-context. Make no mistake, Cliff is quite the master of verbal trickery, taking care that he nearly never says outright what he obviously implies so often.
rockspyder, thank you for bringing up reliability. This is another reason I strongly favor the Axis lock. Aside from the frame lock, the Axis lock is the most resistant to failure due contamination, and the Axis is more wear-resistant than the frame lock (thought that margin is quite small for a well-made frame lock).
How's that, y'all? I hope I was able to keep the wording on a fairly readable level, although Dew's request made some engineering terminology unavoidable. If anyone would like further explanations of any of the terms, perhaps emailing me would be a good idea; I could then post all the explanations at once (assuming any requests are actually made), rather than crowding this thread with fifty more posts explaining terminology.
--JB
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e_utopia@hotmail.com
Now look what I've done ...
Joe: thanks for the well-written message. That's what I wanted to say but you said it much better. Yes, I am also interested to hear Steve Harvey's experience with the lock.
I may have mentioned Cliff a lot in this thread because of the recent controversy. I should say that I always enjoy reading reviews from many others, most of the BFC moderators, Steve, etc. It's a real pleasure to read a well-organized review that concentrates on the knife instead of "how much I know," shows clearly and only what the audience need to know, and most important never disparages others' work (disparages a material is OK to me
).
I wait to see more coming from all of you.
I have some other concern on the rolling-lock, related to reliability/corrosion resistance. In that website (I couldn't remember the URL), the tester put it in mud (very extreme). The Carnivore malfunctioned while liner locks like AFCK still worked. Of course, we don't abuse it that much for normal use, but what happens if I, for example, run into the sea with a Carnivore or Sifu. (Jim have you tried that? )
Can saltwater sneak in and corrode the mechanisms inside? (What are they made of (spring etc.?) Can they corrode?) In this case, do I need to disassemble the knife to clean the parts inside?
TIA,
Dew.
[This message has been edited by Dew (edited 08-29-2000).]
Joe: thanks for the well-written message. That's what I wanted to say but you said it much better. Yes, I am also interested to hear Steve Harvey's experience with the lock.
I may have mentioned Cliff a lot in this thread because of the recent controversy. I should say that I always enjoy reading reviews from many others, most of the BFC moderators, Steve, etc. It's a real pleasure to read a well-organized review that concentrates on the knife instead of "how much I know," shows clearly and only what the audience need to know, and most important never disparages others' work (disparages a material is OK to me
I wait to see more coming from all of you.
I have some other concern on the rolling-lock, related to reliability/corrosion resistance. In that website (I couldn't remember the URL), the tester put it in mud (very extreme). The Carnivore malfunctioned while liner locks like AFCK still worked. Of course, we don't abuse it that much for normal use, but what happens if I, for example, run into the sea with a Carnivore or Sifu. (Jim have you tried that? )
TIA,
Dew.
[This message has been edited by Dew (edited 08-29-2000).]
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Hi All!
Some time I have resisted to take a part in this thread because I already expressed my opinion on lock strength numerous times. Here I can to repeat only: lock strength is important but not the most important thing to care choosing a folding knife. Working with knife properly the lock is not loaded at all. Why nobody ever asks about pivot or stop pin strength? They are really heavily loaded when cutting!
Of course the situation when lock would be loaded can be imagined and simulated, for ex. pulling out the knife plunged into heavy material. But even in this situation I can't imagine a 200 pound (about 80 kg!) load applied with one hand's wrist or even both hand wrists. Breaking locks Frank have used all his weight plus inertia but he did it with premeditation. I really doubt that someone could apply 200 pound plus load unconsciously. But if you do it consciously this is a moment to stop and think: "man, you have a folder in your hands!"
This is the main reason why I'm considering everyone new generation locking device (Axis, Arc, Compression, Rolling and so on) as quite enough strong in comparison with knife normal use conditions and man physical abilities.
Discussion which of them is stronger for me is somewhat onto side of discussion what is better, Easter or Christmas...
In my honest opinion it is no scientific way to simulate the situation when lock could be broken mostly because of completely unscientific character of this situation. This no way means that any data about lock failures are redundant. Quite oppositely, any data obtained in real life situations are much more valuable than all scientific and/or scientific-like talks which lock should be stronger.
Completely another topic is lock reliability, stability, contamination resistance and wear resistance. Unfortunately this discussion is very far from these matters
Some time I have resisted to take a part in this thread because I already expressed my opinion on lock strength numerous times. Here I can to repeat only: lock strength is important but not the most important thing to care choosing a folding knife. Working with knife properly the lock is not loaded at all. Why nobody ever asks about pivot or stop pin strength? They are really heavily loaded when cutting!
Of course the situation when lock would be loaded can be imagined and simulated, for ex. pulling out the knife plunged into heavy material. But even in this situation I can't imagine a 200 pound (about 80 kg!) load applied with one hand's wrist or even both hand wrists. Breaking locks Frank have used all his weight plus inertia but he did it with premeditation. I really doubt that someone could apply 200 pound plus load unconsciously. But if you do it consciously this is a moment to stop and think: "man, you have a folder in your hands!"
This is the main reason why I'm considering everyone new generation locking device (Axis, Arc, Compression, Rolling and so on) as quite enough strong in comparison with knife normal use conditions and man physical abilities.
Discussion which of them is stronger for me is somewhat onto side of discussion what is better, Easter or Christmas...
In my honest opinion it is no scientific way to simulate the situation when lock could be broken mostly because of completely unscientific character of this situation. This no way means that any data about lock failures are redundant. Quite oppositely, any data obtained in real life situations are much more valuable than all scientific and/or scientific-like talks which lock should be stronger.
Completely another topic is lock reliability, stability, contamination resistance and wear resistance. Unfortunately this discussion is very far from these matters
Originally posted by Sergiusz Mitin:
Completely another topic is lock reliability, stability, contamination resistance and wear resistance. Unfortunately this discussion is very far from these matters
[/B]
I for one really like to hear that. Maybe we can start a new thread ?
Dew.
Cliff Stamp
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Dew :
That is not likely to happen on the specific knives mentioned. Neither Benchmade nor REKAT make knives that I am even slightly interested in becuase of a combination of steel choices and customer support. I don't see them as serious heavy use knives.
However when Busse Combat comes out with their folder you can bet that I will get one of them. I will also probably get one of the Buck/Strider folders to use as a Benchmark as right now they are the only ones I see that fit that role. Mission would as well but they would not sell me a MPF.
Having the background in mechanics and materials will allow you to understand the results of working with blades more than someone who doesn't. However the key word is "allow", it doesn't automatically make you able to give valuable advice, it just makes it possible. It enhances the knowledge that you gain from using knives, it cannot replace doing the work.
Sergiusz :
I do agree though that stability is a critical factor and that you should not be focused simply on max breakage strength as without a functional level of stability the lock will fail in low stress use. However the number you quoted (200 lbs) is possible with hand exertion alone.
-Cliff
That is not likely to happen on the specific knives mentioned. Neither Benchmade nor REKAT make knives that I am even slightly interested in becuase of a combination of steel choices and customer support. I don't see them as serious heavy use knives.
However when Busse Combat comes out with their folder you can bet that I will get one of them. I will also probably get one of the Buck/Strider folders to use as a Benchmark as right now they are the only ones I see that fit that role. Mission would as well but they would not sell me a MPF.
Having the background in mechanics and materials will allow you to understand the results of working with blades more than someone who doesn't. However the key word is "allow", it doesn't automatically make you able to give valuable advice, it just makes it possible. It enhances the knowledge that you gain from using knives, it cannot replace doing the work.
Sergiusz :
I do agree though that stability is a critical factor and that you should not be focused simply on max breakage strength as without a functional level of stability the lock will fail in low stress use. However the number you quoted (200 lbs) is possible with hand exertion alone.
-Cliff
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Re Dew's inquiries:
The Rolling lock that I tested was the first generation, with the release lever under the front of the handle scale. It intermittently failed the "stick" test, as I like to call it. I thought it might be due to the release lever being shocked into releasing, but Bob Taylor believed my knife was defective. I have tested the side-release versions of the Rolling lock, even in the larger Sifu format where the stresses on the lock are greater, and I have never had one release during testing.
The Rolling lock is extremely reliable as far as I am concerned. It may fail to be reliable if stuffed with mud, but a liner lock is not reliable any time except possibly when it is perfectly made and perfectly clean. I have routinely failed liner locks by simply applying closing pressure to the blade of a perfectly clean knife with my hand. This would virtually never happen to a Rolling Lock knife.
The Rolling lock that I tested was the first generation, with the release lever under the front of the handle scale. It intermittently failed the "stick" test, as I like to call it. I thought it might be due to the release lever being shocked into releasing, but Bob Taylor believed my knife was defective. I have tested the side-release versions of the Rolling lock, even in the larger Sifu format where the stresses on the lock are greater, and I have never had one release during testing.
The Rolling lock is extremely reliable as far as I am concerned. It may fail to be reliable if stuffed with mud, but a liner lock is not reliable any time except possibly when it is perfectly made and perfectly clean. I have routinely failed liner locks by simply applying closing pressure to the blade of a perfectly clean knife with my hand. This would virtually never happen to a Rolling Lock knife.
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I agree that are so close in strength as to be unnoticed in everyday use. The real question for me is which is more reliable. We place so much emphasis on strength that I sometimes think we forget that reliability is more important. A lock that is super strong and reliable is what we want. I would like to get some input about the reliability of these locks.
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Dennis Bible
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Professor
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Cliff, with all due respect, what folders do you consider "hard use?" Personally owning a Buck Strider and a BM710 Axis, I'd put my money on the Axis for lock endurance, long-term wear resistance, and ultimately, overall reliability. Though the 710's blade geometry and finer point may not be designed for the same level of use/abuse, I'm here to personally testify that the 710 is a tougher knife in many respects as aforementioned than many customs.
I was just wondering what folders you had in mind for "hard use" first and foremost. When I think about what I get for the money with the BM Axis series at street prices, I wonder why I'd even consider using any else as users. Thanks.
Professor.
[This message has been edited by Professor (edited 08-29-2000).]
I was just wondering what folders you had in mind for "hard use" first and foremost. When I think about what I get for the money with the BM Axis series at street prices, I wonder why I'd even consider using any else as users. Thanks.
Professor.
[This message has been edited by Professor (edited 08-29-2000).]
Cliff,
Regarding ultimate lock stregnth, can you give me a practical example of a situation that you would actually stress the lock of a folding knife so that the lock actually fails due to the force applied to it alone? This includes bent liners (not slipped), sheared/bent axis lock pins, etc.
-Johnny
Regarding ultimate lock stregnth, can you give me a practical example of a situation that you would actually stress the lock of a folding knife so that the lock actually fails due to the force applied to it alone? This includes bent liners (not slipped), sheared/bent axis lock pins, etc.
-Johnny
Cliff Stamp
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John :
Last time it happened to me I was cutting heavy rope (1"+) attached to a canvas wrap which was the roof of a large tent for an outdoor celebration. The wrap was not tied down properly and in the middle of the cut the wind got under the wrap and yanked it free. As a result there was a hard pull on the cord which twisted the knife in the middle of the cut so it rolled in my hand and a sudden heavy force went across the back of the blade.
I have had similar things happen a few times and have seen them happen to others as well. One that comes to mind was just during some whittling when the blade twisted. This was using a SAK and the insecure handle was the cause. A better grip would have prevented it - of course a lock would have eliminated the cut.
Professor, based on the attitude of the makers and the level of customer support, without having used them I would be interested in the Busse Combat and the Strider/Buck folder as serious use folders. The Sebenza is very good profile wise as well as lock, but the handle ergonomics don't suit me well. The Gunting from Spyderco is another choice. While heavily combat influenced, the trainers I have handled look to make a solid using knife. The lock is secure and passes all torquing and whack tests. No idea about the strength but I would assume it is fairly high.
-Cliff
Last time it happened to me I was cutting heavy rope (1"+) attached to a canvas wrap which was the roof of a large tent for an outdoor celebration. The wrap was not tied down properly and in the middle of the cut the wind got under the wrap and yanked it free. As a result there was a hard pull on the cord which twisted the knife in the middle of the cut so it rolled in my hand and a sudden heavy force went across the back of the blade.
I have had similar things happen a few times and have seen them happen to others as well. One that comes to mind was just during some whittling when the blade twisted. This was using a SAK and the insecure handle was the cause. A better grip would have prevented it - of course a lock would have eliminated the cut.
Professor, based on the attitude of the makers and the level of customer support, without having used them I would be interested in the Busse Combat and the Strider/Buck folder as serious use folders. The Sebenza is very good profile wise as well as lock, but the handle ergonomics don't suit me well. The Gunting from Spyderco is another choice. While heavily combat influenced, the trainers I have handled look to make a solid using knife. The lock is secure and passes all torquing and whack tests. No idea about the strength but I would assume it is fairly high.
-Cliff
Professor
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I'd like to get my mits on that Gunting, too. It looks a little specialized for my purposes, but maybe Spyderco will incorporate the lock into new, more utilitarian designs. I understand they redesigned it (the locking mech) slightly to make it more user-friendly; apparently it was hard to release one-handed. Looks like strong stuff.
Professor.
Professor.
Steve and Dennis: Thanks!
Yes that's the website. Look at that scary, muddy test.
I asked a few questions above because a while ago someone reported his wife washed a custom folder and it rusted inside. Then don't even think about this test.
Or is it just a "washer failure" ?
Dew.
[This message has been edited by Dew (edited 08-30-2000).]
Yes that's the website. Look at that scary, muddy test.
I asked a few questions above because a while ago someone reported his wife washed a custom folder and it rusted inside. Then don't even think about this test.
Or is it just a "washer failure" ?
Dew.
[This message has been edited by Dew (edited 08-30-2000).]
You're saying that the wind which pulled at the canvas and pulled the rope was strong enough to bend your liner from your liner lock or shear or bend the pin in your axis lock to make it fail? You're saying you were actually strong enough to hold onto the knife during this very sudden occurance and held on tight enough with one hand that the liner or pin bent? You're saying the wind was strong enough to cause this?
How does making a cut of 1" thick rope cause the knife to twist and have such a heavy force applied to the back of the blade to bend the liner?
How do these "twist" actions while whittling put enough pressure to the back of the blade to cause the liner or pin to bend/shear?
-Johnny
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