Why is lock failure even a topic?

I’ve had a couple lock failures, a couple cuts too. Nothing too serious thankfully.

I used to work in a warehouse and you often bump the spine against the metal racking while cutting. It was important that a lock could withstand a moderate spine whack to prevent this. Fixed blades were not permitted. I don’t do that type of work anymore but I still test any new knife against my workbench before it gets put to work. It doesn’t have to hold up to 1000lbs hanging off it or anything ridiculous, just a decent bump.

I tend to grip my tools tightly, and have found on many lockbacks my grip partially releases the lock and makes them unsafe for me to use. I won’t buy a lockback that I can’t hold first or easily return in case it’s an issue.
 
Comeuppance said:
It’s a fixation that affects many people, but why? There’s no rash of lost fingers, I don’t know if I’ve ever seen someone say the lock on their decent-quality knife failed while doing reasonable knife tasks.

It just seems like a bunch of people hitting the spines of their knives for no reason, as if they anticipate needing to swing their knife behind them blindly and need it to withstand an impact.

The only person I know who lost part of a digit to a knife was an acquaintance that drunkenly stabbed a junk-quality knife into a tree while holding it in a reverse grip.

That’s an extreme case of a non-knife task being done with what was already an accident waiting to happen. I don’t think your ZT is going to suddenly lop your fingers off while you cut open that amazon box.

I’ll admit, though, that my entire opinion on the matter is 100% anecdotal. I’m open to contrary opinions. Maybe you have a contextual use-case where inadvertent spine impacts are a real consideration?
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It's a matter of coolness, I think. Everyone wants a car that can hit 200, or a gun that you'll never have to clean, even if no one actually needs it.
 
I think it's simply the way we're wired. The average human doing only pays attention to things when they aren't working right. So, all the times when your knife works as expected don't mean much in your head, compared to that story you heard one time on the Internet about that guy who tried to chop down a tree with his folding knife....

But, seriously. I did have a framelock start to move on me, once. The knife was dull, and I was trying to "power through" some heavy rubber belting material. I felt the lock move, stopped immediately, and went to get a hacksaw.

Part of the problem is also that a place like this can be an "echo chamber", where small problems get bigger and louder, by virtue of being discussed in detail, and repeated at intervals.

I think it's easy to forget that a knife should be thought of as a specialized tool, and also as part of a larger kit of tools, each of which does some things better. I'm not advocating carry a hacksaw and a hatchet everywhere with you, but I guess you could.

I don't know what (if any) responsibility we have to help people keep these things in perspective, but I kinda feel like, if somebody shows up with concerns, it's an opportunity for us to welcome and educate.
 
spine whacking to test lock strength is ridicules I think ! I wouldn't use my skill saw just to see if it cuts backwards or fails, I have always herd if the lock face angle and lockbar is done properly it shouldn't fail under normal use, but I understand there's other lock types on folders besides your basic frame lock though, maybe people like to think they have the strongest folder!I do not no.
 
Comeuppance said:
It’s a fixation that affects many people, but why? There’s no rash of lost fingers, I don’t know if I’ve ever seen someone say the lock on their decent-quality knife failed while doing reasonable knife tasks.


Maybe you have a contextual use-case where inadvertent spine impacts are a real consideration?
Click to expand...


I don't want to speak for them, but here are examples from two Blade Forums members demonstrating why lock strength can be important. I apologize for the screen shots, but I couldn't quote the original posts because the thread was locked (it referred to Cold Steel, so naturally it would be destined for locking!).

IMG-6147.jpg


IMG-6146.jpg



I already had determined for myself that lock performance was pretty crucial decades before I read this. But these two stories stuck with me and further hammered home the point.

-Steve
 
Comeuppance said:
It’s a fixation that affects many people, but why? There’s no rash of lost fingers, I don’t know if I’ve ever seen someone say the lock on their decent-quality knife failed while doing reasonable knife tasks.

It just seems like a bunch of people hitting the spines of their knives for no reason, as if they anticipate needing to swing their knife behind them blindly and need it to withstand an impact.

The only person I know who lost part of a digit to a knife was an acquaintance that drunkenly stabbed a junk-quality knife into a tree while holding it in a reverse grip.

That’s an extreme case of a non-knife task being done with what was already an accident waiting to happen. I don’t think your ZT is going to suddenly lop your fingers off while you cut open that amazon box.

I’ll admit, though, that my entire opinion on the matter is 100% anecdotal. I’m open to contrary opinions. Maybe you have a contextual use-case where inadvertent spine impacts are a real consideration?
Click to expand...
Probably it is CS fault ...they make something totally unnecessarily on folder knife and they make that funny test.When I watch that first /and only time / scratching my head all day and asking my self why the hell they test knife in that direction , opposite from force which we applied on knife when cutting ? It s like instead of crash test we stretch cars for test
 
spyderg said:
I’ve had a couple lock failures, a couple cuts too. Nothing too serious thankfully.

I used to work in a warehouse and you often bump the spine against the metal racking while cutting. It was important that a lock could withstand a moderate spine whack to prevent this. Fixed blades were not permitted. I don’t do that type of work anymore but I still test any new knife against my workbench before it gets put to work. It doesn’t have to hold up to 1000lbs hanging off it or anything ridiculous, just a decent bump.

I tend to grip my tools tightly, and have found on many lockbacks my grip partially releases the lock and makes them unsafe for me to use. I won’t buy a lockback that I can’t hold first or easily return in case it’s an issue.
Click to expand...

I had something like this in mind when I was trying to imagine a situation where spine pressure and impacts occurred. I was thinking maybe HVAC or auto work, where parts are very close together / difficult to reach.

Thank you for sharing. It’s rare to see inherently practical considerations.
 
Comeuppance said:
I had something like this in mind when I was trying to imagine a situation where spine pressure and impacts occurred. I was thinking maybe HVAC or auto work, where parts are very close together / difficult to reach.

Thank you for sharing. It’s rare to see inherently practical considerations.
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No problem, I didn’t read through every post carefully but it seemed to not be getting mentioned. Also, I’ve encountered lock failure while backing out of dense materials. Again no fixed blades were permitted so a solid locking knife was the only option. Those little box cutters were not up to many tasks I encountered. They can be downright dangerous when they snap and pieces fly off too!
My work knife ended up being my Cruwear Spyderco Manix 2.
 
Comeuppance said:
It’s a fixation that affects many people, but why? There’s no rash of lost fingers, I don’t know if I’ve ever seen someone say the lock on their decent-quality knife failed while doing reasonable knife tasks.

It just seems like a bunch of people hitting the spines of their knives for no reason, as if they anticipate needing to swing their knife behind them blindly and need it to withstand an impact.

The only person I know who lost part of a digit to a knife was an acquaintance that drunkenly stabbed a junk-quality knife into a tree while holding it in a reverse grip.

That’s an extreme case of a non-knife task being done with what was already an accident waiting to happen. I don’t think your ZT is going to suddenly lop your fingers off while you cut open that amazon box.

I’ll admit, though, that my entire opinion on the matter is 100% anecdotal. I’m open to contrary opinions. Maybe you have a contextual use-case where inadvertent spine impacts are a real consideration?
Click to expand...
We've been lured into this sort of thinking by salesmen and marketers. My knife purchases never take these claims of super duper lock strength into account. In fact, because I came up with non-locking knives (SAKs, folding fishing knives, stockmans, etc.) I always treat my locking blades with care and I have no qualm using a marginal locking mechanism (such as an Opinel) for robust tasks.

But Lynn Thompson's gotta feed that belly, so he'll keep pushing his super duper locking knives!

Zieg
 
I'll admit that I feel strongly about this topic. For me, it's a combination of factors.

1) That an expensive knife shouldn't have problems with lock geometry and design, or any other part of its execution, even if you don't intend to use it in a way where that matters. Full-stop. To me, this is akin to wanting your sports car to be capable of the performance you've paid for, or to wanting a knife with good steel to have a good heat treat. Some things should just be correctly done. What you're paying for should be what you get, period. It's fascinating to me that people care more about Benchmade shipping out knives with blades that aren't centered than about ZT shipping knives that don't have correct lock geometry (I've seen this first hand on my own ZTs, so drop the nonsense about how it's a few isolated instances).

2) Because locks don't matter until the one instance where they do, and then they're worth the knife's weight in gold. Locks allow for knives to make plunge cuts safer, they allow for you to pull a wedged knife out of cardboard/rubber/foam/plastic safer, they allow you to get away with being less attentive regarding how you hold the knife while moving around and working (like the example above of the spine hitting solid objects while in a warehouse/HVAC work/auto work/construction/home improvement situation, and in general are going to make it easier to operate a knife without being cut. I can still be smart about how I use a folding knife and not rely on the lock to be safe, but still have the lock as additional insurance, just like how I can carefully drive a car with a working seatbelt having never been in an accident and still feel strongly about having a working seatbelt in my car.

3) Because it looks like some knife makers don't understand what they're doing. As Michael Walker would probably tell you, frame and liner locks are more difficult to get right than most people acknowledge. It seems like a number of OEMs nowadays use unsafe lock geometry, poor lock designs, non-existent lockbar tension, and improper lock surface finishes/treatments on their blades and seem to not to realize it. Why should I assume that those OEMs only get the locks wrong on their knives if those same people are in charge of heat treat/fastener choices/blade grinding/handle work/general design?

This is an especially sensitive topic for me because I've had a disturbing number of expensive knives that would reveal lock issues with static hand pressure on the spine of the blade. I don't do spine strikes to test a lock, so if the lock shifts in my bare hands or the blade closes rather than seizing open like it's supposed to, that's a problem. I have not been cut with any of my knives due to failing locks; however, I also check every single knife the instant I get it and get rid of any that have weak locks, so read into that how you will.
 
Axis, compression, spyderco lock back.

If you are really concerned about lock strength, you'll figure out how to carry a fixed blade.
 
I had a lock fail. Or more accurately wear out. Thing is it was probably like that for a long time before I realized it. Because I don’t rely on locks. So I never stress the knife in the close direction.
 
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