What is the purpose of a spine whack test?

Well that question comes up every year, once or twice.

To me, spine whacking is a way to proof lock reliability. To me, those kind of tests and the customers demand for a folder, that can do nearly all, have lead to strong locks. I mean, look, how strong locking folders are nowadays. Consider Axis Lock, Compresion lock, some back lock models and so on.

I don´t see, why ppl. talk about those knives as they were slipjoints. They are really strong.
I have had a BM 520 that failed spine whacks and got a replacement. I believe, BM has changed things nices then (since 2005).
 
SpacemanSpiff23 said:
Isn't it about as useful a test as plunging the blade between 2 rocks and then yanking it to one side?

When would a situation ever come up where that much force is applied to the back of the blade in one violent strike like that? It is a completely unreasonable test to perform.
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To prove that one (he or she doing the "test") is credible at an unknown "science" when in all reality proving that 'they' are slightly developmentally retarded.

There is the CORRECT answer I am happy to report.
 
stabman said:
I like stabbing things like trees and other things you shouldn't with a folder.
Stabbing is a better test of stabbing than spine bashing. I DO test lock integrity first, with progressively applied pressure to the spine or tapping the spine with the second knuckle of the middle finger to get the "feel" of the lock. If you've tested enough locks, this will tell you what you need to know.
I'm a stabbaholic and I still have all my fingers!:D
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Do you stab testers wear any sort of protective gear? I've wanted to stab a knife a few times but wouldn't dare, for fear of losing my digits. :eek:
 
cziv said:
Do you stab testers wear any sort of protective gear? I've wanted to stab a knife a few times but wouldn't dare, for fear of losing my digits. :eek:
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Probably should.:o I have some.
I've just stabbed away at things with knives which I was fairly certain from gentle testing of the lock would not fail (hand pressure on spine, knuckle tap on spine for "feel" of lock).
The stabs were more for fun:), and testing the stabbing characteristics of the blade and point geometry rather than testing the lock.
If the lock failed on a high power stab, I'm not convinced the gloves would fully save one anyway, due to the "cigar cutter" effect; can't hurt to wear them though.
Also, stabbing puts less pressure on the lock than people often think in a knife designed to take it. Take a look at how the point lines up with the pivot and stop-pin; on many knives, the point sits on a line which falls between the pivot and blade stop, meaning that THEY will take much of the pressure (like on an Umnumzaan).
Of course on some knives this is not the case, and the lock will come into play more (like a Strider SmF, especially on a low-line stab).
Odd angles of stabs can also put the forces in weird areas, but still moreso on some knives than others.
 
A. It's a test of the lock. Not a perfect test, but it gives an indication of the reliability of the lock. If lock reliability and strength is irrelevant, we all could be using slip joints. At least to some people the lock and how it will hold up under stress, is important.

B. Accidents will happen, I've accidentally knocked the back of a blade on a hard surface on several occasions.

C. If a folder is stuck in wood (or a similar material) pulling it out might put pressure on the lock similar to a spine whack.

D. At some point the need might arise to give something a whack when the only available item to whack with is a folder... I don't carry a toolbox with me everywhere I go.

E. Knife manufactures often claim that one of their products is extremely tough, reliable etc. Why not put those claims to the test?

Rafael
 
RafaelHerschel said:
D. At some point the need might arise to give something a whack when the only available item to whack with is a folder... I don't carry a toolbox with me everywhere I go.

Rafael
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Use the butt of the knife while closed; don't use the spine of the blade.
 
stabman said:
Use the butt of the knife while closed; don't use the spine of the blade.
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I can think of scenario's were that would be impractical (I don't want to get my hand to close to ...). But that's not the point. I rarely feel the need to whack anything with a folder.

But if I buy an expensive knife that is marketed as tough, with a strong and reliable lock I want the choice to whack it on the spine without the knife closing.

I have an 8 year old Endura that has survived abuse above and beyond it's intended use. It has also survived numerous intentional spine whacks, without closing. The point has broken off at some point but the knife still works fine.

I'm not going to accept anything less from a folder unless I have a compelling reason to do so.

Rafael
 
RafaelHerschel said:
I can think of scenario's were that would be impractical (I don't want to get my hand to close to ...). But that's not the point. I rarely feel the need to whack anything with a folder.

But if I buy an expensive knife that is marketed as tough, with a strong and reliable lock I want the choice to whack it on the spine without the knife closing.

I have an 8 year old Endura that has survived abuse above and beyond it's intended use. It has also survived numerous intentional spine whacks, without closing. The point has broken off at some point but the knife still works fine.

I'm not going to accept anything less from a folder unless I have a compelling reason to do so.
Rafael
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Now that's a great reason :thumbup:
 
powernoodle said:
Spine whacking is pretty useless, in my opinion. It applies force to a blade in a manner, and in a direction, which virtually never occurs in the real world. One might as well shoot the blade with a .22 and call it a spine shot test, in order to test what would happen if the blade were shot.

It is true that force might be applied to the spine in real world usage, like getting a blade stuck in some drywall and wiggling it out. So I understand why some people do it. But even the drywall example does not apply a shock to the spine like a spine whack does.

But mostly I think its just an excuse to play with a knife. Nothing wrong with that.

I don't use folders in a manner which applies force to the spine, so I pretty much ignore spine whack tests. As a general rule, I use the sharp side of the blade. :)



That pretty much says it for me.
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What he said :thumbup:


-Freq
 
I tend to prefer stouter tools when I'm at work (I'm a woodworker).
The spine whack is a relevant test for me.
Stuff will be dropped, borrowed by someone who doesn't give a flip about my tools and is likely to abuse it and stuff will often be used hard.
If a knife is likely to be a slipjoint under certain circumstances I'd like to be aware of it.
It's good to know what your tools can and can't do.
 
powernoodle said:
Spine whacking is pretty useless, in my opinion. It applies force to a blade in a manner, and in a direction, which virtually never occurs in the real world. As a general rule, I use the sharp side of the blade. :)
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Slipjoint guy huh?:p

Using this logic, there really is no need for a lock then, right?
 
termiteslayer said:
I tend to prefer stouter tools when I'm at work (I'm a woodworker).
The spine whack is a relevant test for me.
Stuff will be dropped, borrowed by someone who doesn't give a flip about my tools and is likely to abuse it and stuff will often be used hard.
If a knife is likely to be a slipjoint under certain circumstances I'd like to be aware of it.
It's good to know what your tools can and can't do.
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Funny thing about that.
Most slip joints will pass a spinewack test with no problems. ;)
After I found that out I don't really put to much importens into the test. :D
 
So , the arguement is whether or not an individual finds the spine whack to be a relevant test of lock strength ?

If so , isnt this thread nonsensical ? I mean if every individual interprets this 'test' or anything else for that matter in their own way , what is the point of the disagreement , other than to attempt to prove you are right and the other side is wrong ...

I'm right ! :D

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A spine whack is akin to driving your car in reverse to see how well it will go in 1st gear...
 
After all is said and done, some guys believe in the validity of spine whack testing and some do not. The people who use spine whacks to test lock reliability and strength will do it and will make their decisions partly on the results. For the people who don't think spine whacks are valid, they make their decisions based on other factors.

We all act according to our beliefs. And since there is so much difference here we should all just agree to disagree about the validity and stop making snide remarks on what we don't happen to agree with.
 
Folderguy said:
A few minutes ago I visited Youtube to check out some Emersons. And I came across a video about by a fellow who has had some trouble with the linerlock on a CQC-8.

It's worth watching this two minute video. He had some trouble and sent it to Emerson, it came back from them, supposedly fixed... Check it out:

http://www.youtube.com/watch?v=Ts8EsAtxOrk&feature=watch_response
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That was a bummer, I have 2 of those knives, 1 is NIB and they BOTH do the same thing. I never noticed as I don't usually carry them. :(
 
Folderguy said:
A few minutes ago I visited Youtube to check out some Emersons. And I came across a video about by a fellow who has had some trouble with the linerlock on a CQC-8.

It's worth watching this two minute video. He had some trouble and sent it to Emerson, it came back from them, supposedly fixed... Check it out:

http://www.youtube.com/watch?v=Ts8EsAtxOrk&feature=watch_response
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i watched the video, and i dont know what you want us to be checking out. the lock was apparantly fixed.

no way to tell if the pivot is loose, if the noise is the stop pin, etc. i cant even tell which way he is wobbling the blade (vertical v. horizontal).
 
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