Spine taping a lock to induce lock failure?

skyhorse said:
I'll have to go now, gonna drive into a retaining wall at 50MPH and check out the air bags. :)
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I guess everything is black or white, full smash or nothing at all. No in between. If only there was a color that was a mix of black and white.. hmm.

Not everything has to be a smash or nothing lol if a lock should fold under any negative pressure then what is the point of the lock? Only slipjoints should be made then.

I don't understand the people who can't understand a middle ground.
 
shinyedges said:
No difference apparently.
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So how much force would you say is involved in the spine tap lock test? To be a reasonable test it has to simulate the toughest conditions that the knife would be reasonably subjected to in real use conditions. I would expect any modern high quality folder to stand up to a typical "cop knock" at least.
 
danbot said:
So how much force would you say is involved in the spine tap lock test? To be a reasonable test it has to simulate the toughest conditions that the knife would be reasonably subjected to in real use conditions. I would expect any modern high quality folder to stand up to a typical "cop knock" at least.
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I honestly don't know the precise pound it should hold. If I can make it fail by tapping against my hand, that is to weak for me. I had a zt that would fail a spine tap on my hand.

I don't see any benefit to whacking the hell out of it, but I do see a benefit to ensuring the lock will hold the blade open against the random pressure that could occur from being knocked into something else, or a hard puncture.
 
Allow me to relate an interesting experience - I was hiking through a local nature reserve when I came across a section of path that was overgrown with new growth blackberry shoots. The walk back the way I had come was out of the question as it was too far. I used a Camillus CUDA MAXX clip point framelock folder I was carrying to hack at the shoots. After a couple of swings which severed the shoots the lock failed and the blade closed on my finger. The cut wasn't deep as the closing movement of the blade was quite slow. The lock had never failed before. So why did the lock fail? It was the jarring effect of the blade hitting the 1/4 - 1/2" thick shoots that caused the failure. The movement here is similar to the hanging rope cutting test. It's the same jarring effect with a spine tap.

I once owned Buck models 882 & 889 (liner locks) which also failed very light spine taps.

Neither the Bucks nor the Camillus failed when exerting consistent backward pressure on the back of the blades.

With the Bucks I discovered this when I knocked the back of the Buck knife on a shelf as I pulled back from a cut. The blade dropped like the nose on a Concorde.

I have seen similar failures with other lock types.

When I hike the paths now I carry a KABAR or a Cold Steel short machete in my pack.
 
danbot said:
So how much force would you say is involved in the spine tap lock test? To be a reasonable test it has to simulate the toughest conditions that the knife would be reasonably subjected to in real use conditions. I would expect any modern high quality folder to stand up to a typical "cop knock" at least.
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When working at odd angles in cramped spaces, underneath a train for example, in high stress situations, you can end up hitting any tool (by accident) surprisingly hard. Non-pointy knives are preferable, usually, but if it must be a folder then I’d want something that could take a serious knock without failing. I realise this is a niche scenario and thankfully I don’t have to do anything like that these days.

That having been said, I do not and never have subjected any knife to the almighty thwacks one sees on YouTube!
 
Lazydog1 said:
Allow me to relate an interesting experience - I was hiking through a local nature reserve when I came across a section of path that was overgrown with new growth blackberry shoots. The walk back the way I had come was out of the question as it was too far. I used a Camillus CUDA MAXX clip point framelock folder I was carrying to hack at the shoots. After a couple of swings which severed the shoots the lock failed and the blade closed on my finger. The cut wasn't deep as the closing movement of the blade was quite slow. The lock had never failed before. So why did the lock fail? It was the jarring effect of the blade hitting the 1/4 - 1/2" thick shoots that caused the failure. The movement here is similar to the hanging rope cutting test. It's the same jarring effect with a spine tap.

I once owned Buck models 882 & 889 (liner locks) which also failed very light spine taps.

Neither the Bucks nor the Camillus failed when exerting consistent backward pressure on the back of the blades.

With the Bucks I discovered this when I knocked the back of the Buck knife on a shelf as I pulled back from a cut. The blade dropped like the nose on a Concorde.

I have seen similar failures with other lock types.

When I hike the paths now I carry a KABAR or a Cold Steel short machete in my pack.
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I had a zt 0560 fail that same task, chopping a small less than 1/4" branch caused the lock to fail. I assume it was from the shock.

I own more zt knives than any other knife so I'm far from a zt hater. But I won't sugar coat anything either.
 
Really the spine tap test is just a form of batoning. And why would you baton with a folder? Its almost guaranteed to destroy the lock! Maybe not every knife every time, but the risk is high. Obviously a lock should not fail just tapping the spine on your hand, something is legitimately wrong there.
Lock failure is most likely being caused by "the wrong tool for the job" if everything else is otherwise fine.
 
shinyedges said:
I had a zt 0560 fail that same task, chopping a small less than 1/4" branch caused the lock to fail. I assume it was from the shock.

I own more zt knives than any other knife so I'm far from a zt hater. But I won't sugar coat anything either.
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I think with any mass production knife there are bound to be issues, one of the reason I like large flipper tabs is protection. Now, I never had an issue with any of my ZT Hinderers, but I had a ZT 0620 that from the lightest would disengage. I later owned 2 ZT 0630 that didn't have that issue. Out of the 15+ ZT's i've owned I have only had that issue once. I agree with you, I think some sort of negative force test is important. After I noticed the slipping with the 0620 I switched to my 0560BW. I was working in a tighter space and the the knife blade got kinda stuck, the material I was cutting into had some extremely sticky material on the inside, so to get it out I pulled upwards, and the force needed was more than I expected, on my pull upwards the top of my knife hit a wooden beam hard. Thankfully the 0560 didn't have any issues, and even if it did the flipper would of caught my finger and not the blade, but I remember thinking i was lucky I switched knives or I would of most likely needed some serious stitches. I've never made this mistake, or been in a similar situation again, but accidents/weird things do happen in life that you weren't expecting (isn't that why we often carry knives) so I think it is important within reason to expect a blade to stay open/locked.
 
my opinion is that frame locks are not the strongest folding lock types. they became very popular and are easier to manufacture. I agree they should not fail, but while open are no stronger than a liner lock..... unless being held during use. I've seen knife tests where they fail but do not unlock. they are more apt to fail in the locked position(lockbar traveling over fully and becoming difficult to unlock)
 
Gideons said:
I think with any mass production knife there are bound to be issues, one of the reason I like large flipper tabs is protection. Now, I never had an issue with any of my ZT Hinderers, but I had a ZT 0620 that from the lightest would disengage. I later owned 2 ZT 0630 that didn't have that issue. Out of the 15+ ZT's i've owned I have only had that issue once. I agree with you, I think some sort of negative force test is important. After I noticed the slipping with the 0620 I switched to my 0560BW. I was working in a tighter space and the the knife blade got kinda stuck, the material I was cutting into had some extremely sticky material on the inside, so to get it out I pulled upwards, and the force needed was more than I expected, on my pull upwards the top of my knife hit a wooden beam hard. Thankfully the 0560 didn't have any issues, and even if it did the flipper would of caught my finger and not the blade, but I remember thinking i was lucky I switched knives or I would of most likely needed some serious stitches. I've never made this mistake, or been in a similar situation again, but accidents/weird things do happen in life that you weren't expecting (isn't that why we often carry knives) so I think it is important within reason to expect a blade to stay open/locked.
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I've had 2 0620cfs, 1 of the 0620, 1 of the 0630, and 1 0630cf.
One of the 0620cf had a suspect lock too.

I've had many many zts. Most good, a few suspect. I still have 6 or 7 of them, 2 0452ti's
An 0452cf, 804cf, 0095s90v, and a few others.

Now I wave any knife with either a bolt on wave that I machine or wave I machine and weld on. So I don't need the knives that come with a wave. Way more options when you're a machinist.
 
Popsickle said:
my opinion is that frame locks are not the strongest folding lock types. they became very popular and are easier to manufacture. I agree they should not fail, but while open are no stronger than a liner lock..... unless being held during use. I've seen knife tests where they fail but do not unlock. they are more apt to fail in the locked position(lockbar traveling over fully and becoming difficult to unlock)
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From a physics standpoint I would disagree, a framelock is stronger than a linerlock. However, the "strongest" lock is a very different debate/discussion. Even without the assist of a hand holding the lock in place. A well made framelock with correct angles etc is just as strong as any lock. I could link plenty of abuse videos that show how insanely strong framelocks can be.
 
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