Zero Tolerance Liner Lock Closures?

[Lapedog]

@DocJD please take it as constructive criticism. I’m not trying to pile on you.

 

[bambam99]

For the average owner 99.99% of the time they are cutting cardbord. But it is that .01% of the time that your life may depend on it.

Either way there are people with professions where the odds of them relying on a tactical knife might be much higher.

100 % agree with this.

Its one of my only SD tools I can carry while working.

Apogolies for earlier banter, rough day... we both had our points and it got off topic.

 

[Lapedog]

100 % agree with this.

Its one of my only SD tools I can carry while working.

Apogolies for earlier banter, rough day... we both had our points and it got off topic.

No problem and I apologize too. But I don’t really hold online squabbles against a person.

@DocJD I hope you know we have been friendly for a long time and so I wasn’t trying to insult you in any way.

 

[Pilsner]

You have discussed both fixed and none ZT's and even posted pics . Seems it is thou who art confused .

I for one have mentioned other brands as examples of well made liner/frame locks. That is fully in context. I didn’t mention other locks, as that would not be pertinent. Other people have mentioned other knives, en passant, with relation to the topic at hand. But you, DocJD, repeatedly post about the Triad lock, as if we don’t all know about it, on the most tenuous grounds. What you are seeing is a backlash, and this post is, respectfully, part of it.

 

[firefighterguy]

This thread needs more pictures.

Definately prone to closure with spine whacks.

View attachment 988910

More concisely on topic, firefighterguy how’d your return from ZT turn out?

Honestly, I hesitate to even share my story because I feel like I’ll peobably just get called a liar and people will think I’m making it up. I have zero agenda against ZT. I really just want my knife fixed.

But since you asked, my knife is now on it’s way back to ZT again. They didn’t fix it and said they couldn’t find anything wrong with it. They claim they have spine whacked it and it has never failed once. This is part that I hesitate to post because people will want to claim I’m making this up. ZT says they can’t re-create the issue and doesn’t believe me. Their production managers and qc specialist all put hands on the knife and claim there is nothing wrong with it. In their defense it is hard to fix something that you can’t recreate. However, I don’t understand how I can get the knife out of the box and whack it to my hand ONE time and it fails. I’m not repeatedly whacking the knife. So I asked them if I could send them a video of the knife failing and I did so. The knife failed 5 separate times in a row with a spine whack to my hand on video. The knife has been returned again and their engineer is going to examine the knife to determine the failure.

I made the video private on YouTube out of respect to them to allow them to fix the issue. It’s never been my attention to smear the brand or company. I’ve seen how this thread goes and if it seems unlikely people just claim the posters are lying. I’m just a regular dude like everyone else here. I just like knives and hope this gets resolved

At this point there really isn’t much else I figure they can do if they don’t fix it this time. But I’ve provided them with proof that it fails every single time with a spine whack to my palm.

 

[Lapedog]

Since I live in Canada I can’t send a knife to be repaired. It is liable to get confiscated on the way back in.

Certain repairs I can have done if it is something where I can send the knife with the blade taken out and have them send just the handle back to me. I imagine fixing a frame/linerlock would require them to have the blade.

Luckily my local store still gets ZTs in somehow and I am able to test the knives out before I buy them.

 

[craytab]

You have discussed both fixed and none ZT's and even posted pics . Seems it is thou who art confused .

I've discussed non-zts but I have also focused on the many zts I have and have owned. To say I have discussed none zts is just not factual.

 

[Tommy-Chi]

Curiosity is getting the better of me again. Have you ever had to draw a knife, fixed or folder, in a SD situation? How did it work out, if you did?

I drew a folder from out of my right front pocket to my right hip, and opened it under the duress of 4 to 5 guys kicking and striking me.

Nobody had hit me solidly. They were trying hard to get a hold of me, and I was trying to get away from them.

The knife was not swung, stabbed, thrust, or moved in any way from my hip.

I'd rather NOT do that again. I'm trying to get in to carrying fixed blades that are from 1 to 3 inches in length to stay legal.

I think the knife was a Gerber. I no longer have it.

 

[craytab]

Honestly, I hesitate to even share my story because I feel like I’ll peobably just get called a liar and people will think I’m making it up. I have zero agenda against ZT. I really just want my knife fixed.

But since you asked, my knife is now on it’s way back to ZT again. They didn’t fix it and said they couldn’t find anything wrong with it. They claim they have spine whacked it and it has never failed once. This is part that I hesitate to post because people will want to claim I’m making this up. ZT says they can’t re-create the issue and doesn’t believe me. Their production managers and qc specialist all put hands on the knife and claim there is nothing wrong with it. In their defense it is hard to fix something that you can’t recreate. However, I don’t understand how I can get the knife out of the box and whack it to my hand ONE time and it fails. I’m not repeatedly whacking the knife. So I asked them if I could send them a video of the knife failing and I did so. The knife failed 5 separate times in a row with a spine whack to my hand on video. The knife has been returned again and their engineer is going to examine the knife to determine the failure.

I made the video private on YouTube out of respect to them to allow them to fix the issue. It’s never been my attention to smear the brand or company. I’ve seen how this thread goes and if it seems unlikely people just claim the posters are lying. I’m just a regular dude like everyone else here. I just like knives and hope this gets resolved

At this point there really isn’t much else I figure they can do if they don’t fix it this time. But I’ve provided them with proof that it fails every single time with a spine whack to my palm.

No worries. If you are a legitimate member in good standing you won't get flack for sharing your story. Sounds like you are doing everything you can. Do come back and let us know the results.

 

[Kbrasmodeler]

I drew a folder from out of my right front pocket to my right hip, and opened it under the duress of 4 to 5 guys kicking and striking me.

Nobody had hit me solidly. They were trying hard to get a hold of me, and I was trying to get away from them.

The knife was not swung, stabbed, thrust, or moved in any way from my hip.

I'd rather NOT do that again. I'm trying to get in to carrying fixed blades that are from 1 to 3 inches in length to stay legal.

So, one thing I get from this is, lock strength wasn't a factor in your SD deployment.

Glad you're still around.

 

[Tommy-Chi]

So, one thing I get from this is, lock strength wasn't a factor in your SD deployment.

Glad you're still around.

I'd rather never go through that again, and I'd rather never do it with a folder of any kind.

 

[bambam99]

No problem and I apologize too. But I don’t really hold online squabbles against a person.

@DocJD I hope you know we have been friendly for a long time and so I wasn’t trying to insult you in any way.

Thanks!
Ya me either but much better this way.

Honestly, I hesitate to even share my story because I feel like I’ll peobably just get called a liar and people will think I’m making it up. I have zero agenda against ZT. I really just want my knife fixed.

But since you asked, my knife is now on it’s way back to ZT again. They didn’t fix it and said they couldn’t find anything wrong with it. They claim they have spine whacked it and it has never failed once. This is part that I hesitate to post because people will want to claim I’m making this up. ZT says they can’t re-create the issue and doesn’t believe me. Their production managers and qc specialist all put hands on the knife and claim there is nothing wrong with it. In their defense it is hard to fix something that you can’t recreate. However, I don’t understand how I can get the knife out of the box and whack it to my hand ONE time and it fails. I’m not repeatedly whacking the knife. So I asked them if I could send them a video of the knife failing and I did so. The knife failed 5 separate times in a row with a spine whack to my hand on video. The knife has been returned again and their engineer is going to examine the knife to determine the failure.

I made the video private on YouTube out of respect to them to allow them to fix the issue. It’s never been my attention to smear the brand or company. I’ve seen how this thread goes and if it seems unlikely people just claim the posters are lying. I’m just a regular dude like everyone else here. I just like knives and hope this gets resolved

At this point there really isn’t much else I figure they can do if they don’t fix it this time. But I’ve provided them with proof that it fails every single time with a spine whack to my palm.

No one would call you a liar.
I'm definitely interested in your story, I was hoping it would be fixed when you said you sent it in before.

Since I live in Canada I can’t send a knife to be repaired. It is liable to get confiscated on the way back in.

Certain repairs I can have done if it is something where I can send the knife with the blade taken out and have them send just the handle back to me. I imagine fixing a frame/linerlock would require them to have the blade.

Luckily my local store still gets ZTs in somehow and I am able to test the knives out before I buy them.

Which store is this ?
I think we're both in Ontario and I work mississauga area.

 

[Lapedog]

So, one thing I get from this is, lock strength wasn't a factor in your SD deployment.

Glad you're still around.

Surely you must understand how under sd scenarios the spine of a knife can easily get hit. Even if it doesn’t locks have failed just from
A hard stab.

I don’t see how you can question lock strength being vital for sd use. That is the scenario where it is most likely to be vital.

Imagine I go to stab and miss and as I withdraw the blade the guy brings his arm down and knocks hard against the spine of the blade.

 

[marrenmiller]

So, one thing I get from this is, lock strength wasn't a factor in your SD deployment.

Glad you're still around.

I mean, it sounds like it wasn't even used, so I don't think it would be a factor. The moment you go to use it, then it is very likely to become a huge factor.

 

[Mo2]

Honestly, I hesitate to even share my story because I feel like I’ll peobably just get called a liar and people will think I’m making it up. I have zero agenda against ZT. I really just want my knife fixed.

But since you asked, my knife is now on it’s way back to ZT again. They didn’t fix it and said they couldn’t find anything wrong with it. They claim they have spine whacked it and it has never failed once. This is part that I hesitate to post because people will want to claim I’m making this up. ZT says they can’t re-create the issue and doesn’t believe me. Their production managers and qc specialist all put hands on the knife and claim there is nothing wrong with it. In their defense it is hard to fix something that you can’t recreate. However, I don’t understand how I can get the knife out of the box and whack it to my hand ONE time and it fails. I’m not repeatedly whacking the knife. So I asked them if I could send them a video of the knife failing and I did so. The knife failed 5 separate times in a row with a spine whack to my hand on video. The knife has been returned again and their engineer is going to examine the knife to determine the failure.

I made the video private on YouTube out of respect to them to allow them to fix the issue. It’s never been my attention to smear the brand or company. I’ve seen how this thread goes and if it seems unlikely people just claim the posters are lying. I’m just a regular dude like everyone else here. I just like knives and hope this gets resolved

At this point there really isn’t much else I figure they can do if they don’t fix it this time. But I’ve provided them with proof that it fails every single time with a spine whack to my palm.

Thanks for sharing. Since two others got fixed up recently, it's possible they will fix it now too. How long ago did you send it to them prior?

I think it would be a good idea if we sent them videos before hand too. It just helps them out more.

 

[Yonose]

I drew a folder from out of my right front pocket to my right hip, and opened it under the duress of 4 to 5 guys kicking and striking me.

Nobody had hit me solidly. They were trying hard to get a hold of me, and I was trying to get away from them.

The knife was not swung, stabbed, thrust, or moved in any way from my hip.

I'd rather NOT do that again. I'm trying to get in to carrying fixed blades that are from 1 to 3 inches in length to stay legal.

I think the knife was a Gerber. I no longer have it.

Always good to get rid of the evidence afterward! Seriously, though, I have 3 0350’s (different coatings and one combo edge) that I bought 2-3 years ago and am one of the lucky ones not to ever have this problem.

 

[marrenmiller]

Surely you must understand how under sd scenarios the spine of a knife can easily get hit. Even if it doesn’t locks have failed just from
A hard stab.

I don’t see how you can question lock strength being vital for sd use. That is the scenario where it is most likely to be vital.

Imagine I go to stab and miss and as I withdraw the blade the guy brings his arm down and knocks hard against the spine of the blade.

For those mechanically minded folks, here's a summary of static analysis of a liner/frame lock during a stab:

Visualize drawing a vector from the point of contact (the tip of the blade, most likely) in the direction at which the force is applied. If the vector falls directly in line with or past the pivot (as in the direction above the blade handle towards the blade stops), then the blade stops and pivot handle 100% of the load. If the vector falls between the pivot and the lock bar interface, then even in a stab you are relying at least partially on the lock to hold the blade open (with the exact amount being proportional to how close the vector is to the lock bar interface). If the force vector points directly at or past the lockbar interface point, then the lock is doing 100% of the work holding it open.

How hard do you think you could stab with a blade if your life depended on it? Let's guess you could generate, probably very conservatively, a peak 200 lb load on the knife. Multiply that force by the distance the force vector passes from the pivot. Divide that number by the distance of the lock interface or blade stops to the pivot. Viola, that's how much reactive load those components need to handle. The numbers get drastically bigger as the interfaces are closer to the pivot, or the load vector points further away from the pivot.

You'll probably immediately recognize that it would be very likely, during a wild stabbing motion when fighting for your life, to not land a perfectly positioned and aimed stab on an aggressor, whether because it's impossible to do so or because the knife or your arm is deflected, or because you hit something unintended, or because you reacted to their movements part of the way through, or because the blade landed at an oblique angle and was redirected, etc. Take a look at some of your own folders sometime and you'll see that the allowance for variation on the force vector mentioned above is extremely small. In other words, you'd have to be very careful to avoid putting force on the lockbar, something that is likely to be difficult to remember and even harder to guarantee during a fight. You'd be limited to only slashes, and that's not how people fight with knives.

If your lock slips, it's possible that you have zero second chances and you stand to lose digits on your hand, during one of the most critical points of your entire life. It is true that you should use a fixed blade instead (or a gun, which is a better choice by far), but if you don't have one then I hope you trust your folder locking mechanism.

 

[Pilsner]

Surely you must understand how under sd scenarios the spine of a knife can easily get hit. Even if it doesn’t locks have failed just from
A hard stab.

I don’t see how you can question lock strength being vital for sd use. That is the scenario where it is most likely to be vital.

Imagine I go to stab and miss and as I withdraw the blade the guy brings his arm down and knocks hard against the spine of the blade.

 

[KooKooforKukripuffs]

I'm curious, if you were to sell one of these ZTs that are prone to this failure, but as some here consider it not abnormal, would the seller have to disclose this if they were to happen to sell it here on the exchange?

 

[Yonose]

For those mechanically minded folks, here's a summary of static analysis of a liner/frame lock during a stab:

Visualize drawing a vector from the point of contact (the tip of the blade, most likely) in the direction at which the force is applied. If the vector falls directly in line with or past the blade stops (as in the direction above the blade handle), then the blade stops handle 100% of the load. If the vector falls between the blade stops and the lock bar interface, then even in a stab you are relying at least partially on the lock to hold the blade open (with the exact amount being proportional to how close the vector is to the lock bar interface). If the force vector points directly at or past the lockbar interface point, then the lock is doing 100% of the work holding it open.

How hard do you think you could stab with a blade if your life depended on it? Let's guess you could generate, probably very conservatively, a peak 200 lb load on the knife. Multiply that force by the distance the force vector passes from the pivot. Divide that number by the distance of the lock interface or blade stops to the pivot. Viola, that's how much reactive load those components need to handle.

You'll probably immediately recognize that it would be very likely, during a wild stabbing motion when fighting for your life, to not land a perfectly positioned and aimed stab on an aggressor, whether because it's impossible to do so or because the knife or your arm is deflected, or because you hit something unintended, or because you reacted to their movements part of the way through, or because the blade landed at an oblique angle and was redirected, etc. Take a look at some of your own folders sometime and you'll see that the allowance for variation on the force vector mentioned above is extremely small. In other words, you'd have to be very careful to avoid putting force on the lockbar, something that is likely to be difficult to remember and even harder to guarantee during a fight. You'd be limited to only slashes, and that's not how people fight with knives.

If your lock slips, it's possible that you have zero second chances and you stand to lose digits on your hand, during one of the most critical points of your entire life. It is true that you should use a fixed blade instead (or a gun, which is a better choice by far), but if you don't have one then I hope you trust your folder locking mechanism.

In an actual folding knife sd scenario it is likely that slicing rather than stabbing gets most of the heavy lifting done, with the exception of eyeball/ear/temple. Why I still think if a folder is gonna be used for sd the spyderco military is the best option. ZT’s are probably better at scaring off an opponent and prying/cutting materials is their best use