Buzzbait :
The people who are most obsessed with lock strength tend to be the ones who most fear the ridicule of sheeple.
Fixed blades are illegal in many places where folding knives are not.
I test a production quality lock to see if it will fail under a very stressful load, and break the lock. Where did it get me?
You know now where it failed. In the broad spectrum, if such reporting became commonplace, this information once collected would give a very valuable representation of both the gross properties of the lock as well as the variance in its behaviour. Even if it didn't, it could induce questions from others reading the report and possibly prompt further testing from the maker (if they have not covered it already).
Can I fully expect the next knife of the same model to fail at that exact load?
The expected variation would depends on the QC of the manufacturer so ask them. If they don't know, it would probably be a good time to move on. It is something they should have fully tested.
Or if I have the knife repaired, can I expect the repaired lock to fail at that same load?
It would again depend on the QC of the manufacturer, and how exactly they repair the folder. Ideally you would want a complete replacement of all over stressed parts so it should behave like new.
I~Rm not sure that I trust ANY mass production knife company to guarantee my fingers to any lock ...
People do all the time with lots of objects that are much more dangerous than a lock on a knife. I trust the brakes on my car. They are not an "accidental stopping mechanism" that may or may not work. They are supposed to actually stop the car from moving, and not do so only if I apply the force perfectly perpendicular to the peddle in a slow and controlled manner. Do brakes fail - yes, and people get seriously injured. Nothing is 100%. However does anyone drive as if the brakes might not work - no. And if the failure was due to a defective repair, sloppy assembly, or poor parts would it be tolerated - hardly. Any garage or manufacturer that developed a record for such work would promptly find itself out of customers.
And of course our lives are riddled with such items. If you lock your house you expect that it should stay locked and not be able to be opened by someone jiggling the handle or squeezing it really hard. If any dead bolt manufacturer made such a lock which would be thus opened would they stay in production after the public found out how easy it was to defeat the lock - no they would not. It is the same thing for padlocks and locking mechanisms in general. They are not just supposed to stay locked under very gentle use. We are talking about locks on folders promoted as "heavy duty", "combat", "tactical" etc., not a light use gentlemans knife.
And what if my knife passes a certain nasty stress test? Did I stress the knife to the point that it may be more likely now to fail in the future?
Yes, it is indeed possible that any and all tests you do to a lock will weaken it, just like it is possible that any and all use of a knife in general can lower its tolerance to gross failure. Thus by the same logic you should never use a knife for evaluation purposes because it might lower its performance when it is needed - of course the downside is that you go in to such usage totally blind to the abilities of the tool.
As for using a knife with skill and knowledge so that the lock is never stressed - this means you don't need the lock. The purpose for locking folders is to extend the functionality of the tool. Just like locking tools on a multi-tool allow you to use them with more force that screwdrivers that don't lock.
Anthony Lombardo :
I am curious, are you still promoting the Busse Folder as the strongest avaialable, even though it doesn't exist?
Specifically I was asked [three years ago] what folders I felt were suitable for hard use, I replied :
"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."
Which of course is significantly different than your paraphrase.
[I changed my mind on the Buck/Strider after using it, the compression lock is still there, though not fully tested, and the new "center lock" from Niemi I would put first and I would be surprised if Busse could exceed its abilities in that regard]
Would I expect Busse to make a folder that is more secure than the liner locks I have handled. Yes. Would I expect it to be among the very best I have seen, yes. Why - because I have discussed with him my experience with many locks and I have heard his goals for the folder. But even if this wasn't the case, just based on just general perspective it seems unlikely that he would produce such an unstable lock.
This isn't a difficult concept to grasp. Lets assume you test out a $30 Ontario Bowie. You are now fully aware of its abilities. Jerry Fisk comes along and says I can make you a bowie if you are interested. Would you support the idea that Fisk's bowie would be better without handling it? Who here would actually not take that bet.
There are very few knives that can hold over 200 inch pounds.
200 in.lbs of torque is very low. Any physically active adult man who doesn't have a severe physical injury has greater wrist strength. People with lots of physical hand / wrist activity (construction or hockey) commonly can produce more than 300+ in.lbs of torque. Last time I checked (a couple of years ago) the lowest standard Spyderco had was somewhere close to 150 in.lbs, and the heavy duty models were supposed to be more than three times as high.
A properly fitted hardened Steel frame lock would be as strong as any folding knife needs to be.
Raw strength in a controlled vector isn't the issue outside of promotional hype.
-Cliff
). And I would still be there if it weren't for the fact that there were no slipjoint folders with decent steel, for a decent price (forget any custom folders). Buck had gone to 420HC, and Case was already there (unless you got the cheap yellow with Chrome Vanadium, and I wasn't the impressed even with that). Camillus was slightly better with some 440A, but.... So, when I had to go looking for something to replace my old slipjoint folder, I turned to the "tactical" folder because it was the only thing with good steel. Admittedly, Queen has now gone to a decent steel (D2), but the one sample of their handiwork I got did not impress me at all. I was downright disappointed. So, now I'm a 'tactical' folder fanatic, and because all of those are such easy openers, you HAVE to have a lock. It is a viscious circle. But anyway, like I said, I'm with you. I'd love to have just an old style stockman slipjoint with decent steel and scales (g10 or micarta is fine, wood is great, just don't want slick plastic). Ack! :barf:
