whats the big deal about lock strength?

rogerxd45

rogerxd45

Joined
Mar 12, 2009
Messages
271
so i keep hearing people bring up the strength of various locks. i often hear people say they dont like liner locks because the lock isnt as strong as a frame lock or compression, ect..

i have never seen a lock on any decent knife fail through normal use, actually now that i think of it ive never seen even a cheap chinese flea market knife that had its lock fail.

i even saw a video that demonstrated the strength of various locks and they all were able to hold over 200lbs.

i understand wanting a knife that is over built that you dont have to worry about breaking but i think even a liner lock that can withstand over 200lbs fits those requirements. the other thing i was thinking was that i never use my knife with pressure being applied to the spine. i cant think of any situation in normal use where i have pressure on the spine of the knife where only the lock is preventing the knife from closing on your fingers and i certainly would never have over 200lbs of pressure on the spine. if the lock had pressure on it during normal cutting then i could understand people wanting a super strong lock

so this leads me to my question about why people are concerned about lock strength when even one of the weakest designs is capable of holding very large amounts of pressure. when using a knife correctly there shouldnt be any downward pressure trying to close the knife. the lock style or strength shouldnt matter at all when all the pressure is going in the opposite direction and not putting any pressure on the lock itself.

maybe im looking at this wrong and hopfully someone can explain it to me.
thank you
-Roger
 
Do you want to have a knife close on your fingers? It's not fun let me tell you. Treat every folding knife as if it has no lock.
 
You have to understand that there is a certain amount of over-engineering going on in the knife world. I think it started with clueless knife testers testing their knives not for any realistic cutting task but to failure. It's kind of like horsepower in certain car circles. Nobody knows why you need more but they want it anyway. This leads to manufacturers entering the race to see who can produce the most overbuilt folders because clearly that is what part of the market is after. They are catering to people who want the most indestructible folding thing, I won't even call it a knife.

The lock however, unlike say the blade thickness, is something I am totally OK with people over-engineering. I have had locks fail. For me it has been cheap liner locks, but no lock failure is fun.
 
I've had my fair share of cuts from a lock giving out.

My older brother had to have surgery and wear a cast after a lock failing while piercing rubber (same model knife cut me while opening a box of frozen meat). The lock slipped when piercing cardboard. Slight negative pressure, and bumped a frozen patty.

So I care.

Of coure, I've had my fair share of cuts from fixed blades, so maybe I should not play with knives.
 
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i had not thought about piercing something, that would definitely put pressure on the lock and if the lock failed doing this it could get very nasty!
thanks for pointing that out, its not very often that i need to use my knife to pierce something with the tip so i didnt even think about that.
this is why i love this forum, i am learning new stuff all the time

and dont get me wrong i love over built knives. my zt0801 is a beast! if i have the choice i will opt for a stronger lock but if a given knife is only offered in a liner lock i have no problem buying it.
im not going to pass up a knife i really like because it has a liner lock. i feel that if its a well built knife that whatever lock they use will be more sufficient.
 
I once had a cheap Pakistani made Buck 110 knock off. I'd call it a clone, but it was so bad it didn't even warrant being called a clone. It was a gift from my father and to him, a knife is a knife is a knife so why pay more.

I was using it in the woods. Had to cut through a branch about 1/2 thick, when the lock broke and the blade came backward so that the spine of the blade hit the top of my fingers. No injury or anything but from that point on, i had an absolutely useless knife, and one that if i had thrown it in my pack, it could have swung open and cut other stuff in my pack. So I buried it right out there in the woods in Meriden CT.

Now, the design for the Buck 110 knife is very strong, it was a matter of poor execution in this case, and it resulted in no injury. Nonetheless, a broken lock left me with no knife out in the woods. Had I not been in a local park and only a mile from my car, it would have made me uncomfortable.

Moral of the story- carry a fixed blade in the woods! (or at least a folder with a good strong well executed lock.)
 
You've probably noticed most (if not all) lock strength tests on YouTube are either hanging weight off the end of the handle or spine whacking. Both of these are fairly irrelevant to me and neither really address lock strength in a stabbing motion. Regardless, while Cold Steel swayed me in my early times as a knife enthusiast, I've come to the conclusion that every well made knife I've owned (from $10 to $500) has had adequate lock strength for all my uses.
 
Folding knives (regardless of lock design or strength) are really light duty knives meant for cutting only. (This it the effective reason for treat every knife as if it didn't have a lock.)

If you want a heavy duty, life depends on it, knife, go with a well designed, and made fixed blade. It may still fail, but with a much, much lower probability.

That's my view...
 
Bigfattyt said:
I've had my fair share of cuts from a lock giving out.

My older brother had to have surgery and wear a cast after a lock failing while piercing rubber (same model knife cut me while opening a box of frozen meat). The lock slipped when piercing cardboard. Slight negative pressure, and bumped a frozen patty.

So I care.

Of coure, I've had my fair share of cuts from fixed blades, so maybe I should not play with knives.
Click to expand...

That last line is pretty funny... and may apply to many of us here! Sorry to hear about your brother.

Agreed--the integrity of the lock matters; I get my knives scary sharp... I don't want to be on the wrong side of that edge. Rev's point is an excellent bit of wisdom... I know I need to take that precaution more seriously. :thumbup:
 
What Mr. Rev said.

I treat all folders like slipjoints, and don't think I have ever stabbed, twisted, pried, etc. with my knives. Not once that I can remember. I understand how some guys might do that if they are digging in drywall or whatever, or on a dark-ops mission behind enemy lines, but lock strength has never been an issue with me because I never do anything that requires lock strength. Its not even on my radar. I only slice and push cut, and my locks never have the chance to fail. But I'm not nearly as manly as you guys who dig through brick walls and pry up manhole covers with your EDC knives.
 
It never hurts to test the waters a bit. Any folder I am going to carry gets a little whack on the spine while I am wearing a glove. Only a couple have ever failed, and those got tossed. I don't abuse my knives much, but it is impossible to control every variable every time, and I have occasionally made accidental contact at weird angles. I don't use a knife at work anymore, so the chance of disaster is even lower. But I got bit once trying to cut a bit of gaff tape off of a pipe in bad lighting; I rapped the spine against a pipe clamp on the way in and chopped through my glove and left a (thankfully) small cut on my palm. The CS videos are basically live theater, but they do have a valid point that it is worth knowing that your tool can handle a bit of the unexpected. I just wish that they would set the lock strength tests the music "Madame Guilllotine" from the Scarlet Pimpernel.
 
I've never once had a lock fail on me, even when piercing things. When piercing resistant material it's often possible to orient the point in such a way that lock strain is kept to a minimum, and I usually hold the knife by the flats of the scales so that if the lock somehow did fail my fingers wouldn't be in the way. Any time you do something with a tool that puts strain on it, it's important to "listen" to the tool to identify when it's approaching its working limits. If you can feel the knife responding in a way that indicates strain, either get a better tool for the job or modify your technique to reduce that strain as much as possible while planning for how to respond to potential failure.
 
I stress-test my folders with reasonable closing pressure and light spine-whacks just to weed out any truly dangerously weak locks. So far none have closed on me. I feel confident in their strength, although I generally don't do any heavy-duty piercing or twisting with them.

I recently purchased a Cold Steel American Lawman and have to admit that the Tri-Ad lock does inspire confidence in its strength. If I had to do any serious piercing or twisting cuts and didn't have a fixie, I'd prefer it over a liner lock.
 
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