Spine taping a lock to induce lock failure?

Hickory n steel said:
I get what you're saying, but I'm talking about pinching the blade with your fingers coming around the spine.
You have much more control this way because it limits the length of sharp blade moving around if it slips, it also prevents you from inadvertently putting backwards pressure that could close the knife on you.
This is more Important with slipjoints but any lock could fail on you.
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That still doesn't explain how you are supposed to pierce something that way, like you claimed you could above.

That said, some very primitive folders were used in that way, i.e., by grabbing the blade only. The handle only really functioned as a sheath (something for the knife to fold into).

I found it interseting, as an aside, that when the Scandinavians stab/pierce with their knives...you know, the traditional Moras and leukus without a guard...they cup their hand over the butt of the knife and then stab away...smart!
 
And BTW, just to go on the record...the spine whack test is stupid. Its as informational as seeing if you can fry an egg on your blade.
 
Leo3an said:
Ah thanks. I did not think of blade shutting on the finger as backing out. But i think unless you are testing it by whacking the lock hard, it should not fail when spine whacking. But i maybe very wrong.

I should not rely on the lock for cutting, i understand that... but I do want it to lock strongly even if I should not rely on it.
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And how does spine whacking tell you anything about how the lock functions while cutting?
 
A few years ago I was on a SAK kick and used one everyday on the farm. We grew way to many zucchini and squash and I was cutting them up to feed to the hogs with a super tinker. The blade would bind in the tough squash and the handle would fold. Not a pleasant experience. It put me off using a slip joint for tough cutting.

I like a lock that holds the blade open. Period. Even under a reasonable negative force on the blade.
 
The knife should be able to handle minor spine tapping without failure. Here is my question, how did this person discover the lock would fail from spine tapping in the first place? It is possible the lock became worn or damaged over time if he smacked it on a table frequently.
 
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I don’t spine whack or tap knives, unless I strongly suspect that the lock is not functioning, in which case a light tap.

Most cutting jobs can be done without a lock, safely, with good technique.

However, some people have to work in confined spaces in odd positions, using even more odd actions. Anybody who has done HAZRES, even just the training, will know what I mean. I would always want a locking knife or fixed blade for that, and if it is a locking folder then I want a good lock. I own a lot of Axis locking folders (or to me it is a lot ;)), a Recon 1, a PM2, and those are the folders I would rely on in my collection. I do own others, but I like a bomber lock if things might get ‘awkward’.

Still, I would always advocate a fixed blade for those situations, but it doesn’t always work out that way.
 
Hickory n steel said:
You cut with the edge of a knife which exerts force in the opened position towards the stop pin, lock bar...ect, if you grab a knife's blade towards the tip for safety when trying to pierce something tough you won't have any issues.

In my honest opinion spine whacking is a bullshit irrelevant test.
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I disagree. If it is marketed as a self defense knife then a lock has to protect against some negative pressure against the spine. Even doing non self defense work you could have something fall on the spine or bump it by accident.

I do agree that on liner and framelocks hard spinewhacking is liable to damage the lock.
 
Leo3an said:
Then there is a no need for a lock. Just a friction folder is good enough.
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I agree.
That being said, I like knives, and some if the ones I like happen to lock, some do not. I am fine either way because I am not a moron and I don't Need a lock to make use a knife safely...
 
My opinion: It shouldn't fail because of a spine whack, but if it did fail it wouldn't be a deal breaker for me when it comes into consideration for purchase because it's improper use/testing to begin with. If there were two knives I like a lot and one failed at dealing with a little spine bump I would go for the lock that didn't "fail" (And I am saying bump, like tapping it on the edge of a table, not deliberately smacking the spine on concrete to see HOWDAMNSTRONG™ the lock is).
 
We all know spine whacking is silly, but it is equally as silly to suggest that a lock does not need to be strong enough to hold the blade open with a decent amount of negative pressure. Not all the cuts made are positive push cuts that only exert pressure on stop pins. If you had to pierce very tough rubber, which i do quite often when working, do you actually think a slip joint or a lock that fails under negative pressure is suited for this? You can't always do a piercing cut 100% of the time perfectly without exerting a little positive and negative unless you're doing it very slowly and carefully. Plus human error is a fact of human life so should it cost you your fingers? What about when pulling your knife out of material when its bound up and you cant get the right pull angle in tight spaces? All locks should be able to handle this kind of thing, i'm not talking Tri-Ad lock Cold Steel lock strength, but decent workable lock strength should be there on any lock.

It's almost like saying the lock on your front door only needs to hold the door closed from wind, and it's ok if a slight shoulder bump will bust it open. Because not all door locks are made to be shoulder bumped, just like blades aren't made to be spine whacked.
 
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All my locking knives are made by companies that I'm sure have tested the locking mechanism six ways to Sunday before releasing to the public. I only make sure it's properly maintained to ensure safety.
 
spyderg said:
When using a knife at work, it would often bump against stuff like metal racking. Not hard mind you but before using a knife there I would always test it against a block of wood. As long as it takes a decent bump without failing, good to go. No need for tests like Vininull on YouTube does, although it can make for an interesting video.
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I get all the "you cut with the sharp end" business that always comes up, but I think you make a good point, which is, accidents can happen, the spine of a knife can bump against something, and if the lock fails your fingers might be in trouble. It probably isn't likely but I'm not willing to risk my fingers. I don't spine whack my knives, but I own mostly non-framelocks (Triads, comp lock, ball-bearing lock, Axis). It is also important to me to that my folders my folders have a fingers choil, a flipper, or something that, if the knife lock were to fail, would contact my finger that is not the sharpened portion of the blade. I don't really trust folders, and only use my fixed blades hard. Maybe that is overly cautious, but I like my digits to stay attached. Hard spine whacks seem excessive, but some light taps seems reasonable to me.

Once while camping I bumped the spine of my folder on something and the lock disengaged. It was a flipper, so the flipper tab caught my finger. No problem. I was glad to have the secondary safety feature.
 
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Mick_1KRR said:
We all know spine whacking is silly, but it is equally as silly so suggest that a lock does not need to be strong enough to hold the blade open with a decent amount of negative pressure. Not all the cuts made are positive push cuts that only exert pressure on stop pins. If you had to pierce very tough rubber, which i do quite often when working, do you actually think a slip joint or a lock that fails under negative pressure is suited for this? You can't always do a piercing cut 100% of the time perfectly without exerting a little positive and negative unless you're doing it very slowly and carefully. Plus human error is a fact of human life so should it cost you your fingers? What about when pulling your knife out of material when its bound up and you cant get the right pull angle in tight spaces? All locks should be able to handle this kind of thing, i'm not talking Tri-Ad lock Cold Steel lock strength, but decent workable lock strength should be there on any lock.

It's almost like saying the lock on your front door only needs to hold the door closed from wind, and it's ok if a slight shoulder bump will bust it open. Because not all door locks are made to be shoulder bumped, just like blades aren't made to be spine whacked.
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Thank you. You said this much better than I could have.
 
jstn said:
I get all the "you cute with the sharp end" business that always comes up, but I think you make a good point, which is, accidents can happen, the spine of a knife can bump against something, and if the lock fails your fingers might be in trouble. It probably isn't likely but I'm not willing to risk my fingers. I don't spine whack my knives, but I own mostly non-framelocks (Triads, comp lock, ball-bearing lock, Axis). It is also important to me to that my folders my folders have a fingers choil, a flipper, or something that, if the knife lock were to fail, would contact my finger that is not the sharpened portion of the blade. I don't really trust folders, and only use my fixed blades hard. Maybe that is overly cautious, but I like my digits to stay attached. Hard spine whacks seem excessive, but some light taps seems reasonable to me.

Once while camping I bumped the spine of my folder on something and the lock disengaged. It was a flipper, so the flipper tab caught my finger. No problem. I was glad to have the secondary safety feature.
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Fixed blades weren’t allowed at work. Plus a folder was safer when climbing on and off forklift all day but no time to put knife in and out of sheath or even put it down a lot of the time so a folder was what I used. Often at work I was cutting in tight spaces where it could bump things. Also I can remember a few times when working at a work bench all day then moving to a higher one for some reason I would go to put the knife down and bump it forgetting I moved over to a higher workspace. : / Bottom line is a locking folder should do just that, lock. If it fails due to a “normal” bump it’s not safe. The kind of impact I’ve experienced does not cause a slipjoint to close all the way either, (unless it had perhaps a 0.5 pull!?) I occasionally used a slipjoint at work and I remember bumping but it wouldn’t do more than move the blade say 10 or15 degrees before the spring would pop it back. Again, a couple taps against a board are enough to confirm the lock is engaging properly.

I think one of the issues is some people’s obsession with early lockup. A lock barely making contact is just begging to be tested, lol! I like my linerlocks tabs to be fully engaging the tang but leaving lots of room to travel after years of use. Frame locks, as much engagement as possible while allowing for travel as it wears too.
 
me2 said:
If the knife had a lock, then it should work as a lock. It shouldn't let the blade close unless it is disengaged by the user or enough force is used to damage it.
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I very much agree with this.
 
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