Kershaw Spine Whack Fail

[Twindog]

The lock on a folding knife is a beautiful thing. It’s not there just to prevent accidental closing, but so that the knife can be opened easily with one hand. The ZT 0560CBCF has an amazing bearing system in the pivot that lends itself to the flipper. If you take the lock off the 0560, you’ll have a blade that just hangs and swings freely. The lock allows the easy flipping action in a blade that then locks up securely so that it can be used safely and effectively.

My Rukus, my current EDC, has a huge, heavy blade that swings open easily. The axis lock then secures the free-hanging blade in place safely and effectively. Without the lock, the knife would be unsafe and difficult to use.

If the lock fails under light or medium pressure, it’s actually more dangerous than a slipjoint because it takes the user by surprise before he has a chance to react.

Slipjoints and modern locking blades are two different types of technology. The slipjoint blade has a detent when open; it does not hang free when open, as does the locking folder without the lock. I never use a slipjoint anymore because I love the easy, one-handed opening and closing of the modern locking folder, along with the ability to carry a safe, large-bladed folder.

If you really think that the OP’s first knife failed because of abuse, not design failure, try to sell a knife like that to the public with full disclosure.

 

[Luis G.]

Which is why I consider spine whacking invalid and abusive. Who in their right mind is going to spine whack a knife during its intended usage?
As I said before the design has a known inherently liability that the end user is responsible for having enough thought to comprehend and watch for. Therefore that user should use the knife carefully and as intended because they know it can fold as intended by design.

You are misunderstanding and dodging the point. We are looking at this from a safety concern, not a function concern. I don't use knives as hammers but there has been the occasion where I cut something, and sometimes the spine gets hit due to the confined space.
That's why there's seat belts. No one goes looking to ram into a wall. Accidents happen. Safety mechanisms need to work in these circumstances.

It's not a feature for daily use I don't understand why you keep coming back to this argument when no one has said anything about it. If by accident you do have to use the safety mechanism (knife lock) someone needs to make sure it works. That responsibility usually begins with the the manufacturer and or 3rd party companies.

 

[Karda]

You are misunderstanding and dodging the point. We are looking at this from a safety concern, not a function concern. I don't use knives as hammers but there has been the occasion where I cut something, and sometimes the spine gets hit due to the confined space.
That's why there's seat belts. No one goes looking to ram into a wall. Accidents happen. Safety mechanisms need to work in these circumstances.

It's not a feature for daily use I don't understand why you keep coming back to this argument when no one has said anything about it. If by accident you do have to use the safety mechanism (knife lock) someone needs to make sure it works. That responsibility usually begins with the the manufacturer and or 3rd party companies.

And this is where you are misunderstanding. I don't think many (if any) of these folding knives are marketed as having the locking mechanism as a "Safety Feature", they are marketed as "Folding Knives".

 

[mqqn]

Yea - Cars have brakes, but sometimes there are circumstances that can make the brakes ineffective.

The user has some responsibility in the equation.

If you experience failures with your knives when you are spine-whacking, stop that.

I usually have my hand gripping the lock-bar, holding it in place when I am using a folding knife. Typically, when I am cutting, I am putting pressure on the sharpened portion of the blade, not the spine. Thus, the likelihood of a cut from a failure is minuscule.

best

mqqn

 

[brownshoe]

Per "Who in their right mind is going to spine whack a knife during its intended usage?"

I believe Twindog gave you a direct scenario.

I can testify that I've had a lock-back fail in the same situation. A Puma with about 15 years of use, the lock had worn, so impact popped it open whacking a weed off in some close quarters.

My Cold Steel Tanto Voyager, with the original integral clip, has been used for digging in the garden, splitting stakes and it gets all kinds of twists and impacts, but is as hard as a rock. Is this abuse? not per Lynn Thompson. The AUS8A gets dull and some dents, but it straightens out pretty easy due to the low Rockwell.

Bought a Buck Vantage, flipped great, never tested it. A slight bump on the spine while sitting in an easy chair, blade pops closed and cuts my knuckle. I wish I had tested it. I fixed it with a reset of the pivot and some 400 grit sandpaper on the tang.

I have a Terzuola ACTF, per Bob, impacts on the spine of a "tacictal folder" will not / should not close the blade.

 

[powernoodle]

I don't think many (if any) of these folding knives are marketed as having the locking mechanism as a "Safety Feature"

If the lock is not intended to keep the blade from closing on the user's fingers, then why do the manufacturer's employ it? User safety is the only conceivable purpose of the lock.

I'm not a big fan of spine whacking, but it does reasonably simulate end user usage. Consider the drywall guy who uses his ZT 0200 to install an electrical outlet. He stabs and saws and pries the drywall, and in so doing imparts forces the lock which the spine whack simulates. He gets grumpy because his blade is stuck in the wall stud, so he gets more aggressive with the up and down forces in order to remove the blade. Thats completely foreseeable, and completely within the intended usage (in my view) of a knife "built to stand up to heavy-duty use and harsh, real-world conditions." Link.

The drywall guy reasonably expects the blade not to close on his fingers in "heavy-duty use and harsh, real-world conditions". Ergo, the lock is a safety mechanism. Spine whacking - while imperfect - imparts forces on the lock which reasonably simulate real world usage: the stabbing, sawing, twisting and digging that a 22 year old drywall guy hopped up on Mountain Dew and nicotine will do to his knife during the course of the day. If a knife fails a spine whack, the drywall guy shouldn't be using it.

I don't spine whack my knives, and pretty much "baby" them so this is a non-issue for me. But spine whacking does constitute "some data", and "some data" is better than no data. Its certainly better than developing data when the blade violently closes on your hand at the job site. Just my take.

:thumbup:

 

[Luis G.]

And this is where you are misunderstanding. I don't think many (if any) of these folding knives are marketed as having the locking mechanism as a "Safety Feature", they are marketed as "Folding Knives".

Safety is a very big concern of mine, and not something one can just toss aside by manipulating wording or playing with marketing. People trust knives with their lives, and limbs. Not to make sure they play their favorite music or can watch their favorite movie.

I don't see this conversation going anywhere except downhill with word play, or avoiding the point.

I will just have to respectfully say I strongly disagree with your statement.

 

[Karda]

I've laid a lot of drywall in my life. I've never once used a folding knife for the purpose.
I wouldnt allow anyone I work with to do so either.
Fortunately most carpenters/drywall installers I've known use common sense and use utility knives and drywall saws for their intended purpose.

 

[B.F.U]

Yeah, you don't hit a knife on its spine in normal use. What this shows is that the liner/frame lock is inferior. It's inferior not only on this knife or on Kershaws, but on every knife with a liner/frame lock.

The liner/frame lock is a good lock for normal use. It works well. It is a simple, easy to manufacture lock. This is why it is used so often. NOT because it is the best lock type.

If you want a FOLDING knife that is least/less likely to fail, don't get a liner/frame lock. Get a back lock or its variants, or even a bolt action lock or its variants.

 

[Karda]

Yeah, you don't hit a knife on its spine in normal use. What this shows is that the liner/frame lock is inferior. It's inferior not only on this knife or on Kershaws, but on every knife with a liner/frame lock.

The liner/frame lock is a good lock for normal use. It works well. It is a simple, easy to manufacture lock. This is why it is used so often. NOT because it is the best lock type.

If you want a FOLDING knife that is least/less likely to fail, don't get a liner/frame lock. Get a back lock or its variants, or even a bolt action lock or its variants.

This is common sense folks. Study It. Learn From it.

 

[Luis G.]

So much misinformation. I would strongly recommend if people want to know the truth, to get on youtube and knife maker forums.

Liner locks and framelocks can be made into very strong locking mechanisms. The problem is it requires quite a bit of knowledge in physics, and very tight tolerances.

 

[Twindog]

Yeah, you don't hit a knife on its spine in normal use. What this shows is that the liner/frame lock is inferior. It's inferior not only on this knife or on Kershaws, but on every knife with a liner/frame lock.

The liner/frame lock is a good lock for normal use. It works well. It is a simple, easy to manufacture lock. This is why it is used so often. NOT because it is the best lock type.

If you want a FOLDING knife that is least/less likely to fail, don't get a liner/frame lock. Get a back lock or its variants, or even a bolt action lock or its variants.

A liner lock or a frame lock can be excellent and robust. The Spyderco Military's imbedded liner lock is excellent. The Sebenza's frame lock is awesome. If you took the time to watch the videos that Marthinus provided you'd see that a cheap Swiss Army knife's liner lock easily took powerful blows and did not fail.


A lockback can be poorly fitted or poorly designed and fail easily. Any of these locks can be well made and well designed -- or vice versa. Design, materials and assembly matter.

 

[mqqn]

Yea - how did anyone ever use a knife without cutting off all of their fingers before the advent of the safty-locking mechanisms of today

That was sarcasm, by the way.

best

mqqn

 

[RiderOnTheStorm]

If you can close your "locking" knife with hand pressure then there is a problem, but whacking them on wood or concrete is just abusive.

 

[Twindog]

Yea - how did anyone ever use a knife without cutting off all of their fingers before the advent of the safty-locking mechanisms of today


That was sarcasm, by the way.

best

mqqn

Sarcasm never proves a point, it just degrades the conversation.

The slipjoint is an entirely different design. It has a safety detent spring to keep the blade open.

Try opening that slipjoint with one hand. Try taking the safety detent spring out and see how useful the knife becomes.

The locking knife has huge advantages over the slipjoint: it allows easy, one-handed opening and it allows a very large blade to be used safely. If you don't like the lock on a locking folder, what are you going to replace it with? A detent spring? Are you just going to let the blade swing freely? Comparing a slipjoint to a locking folder is like comparing a slipjoint to a fixed blade. They are very different.

 

[Doughnut]

There is no way I could trust a video that starts by showing a knife with a broken tip... and showing that the lock fails.

Didn't all of the shocking spine whack videos we've seen over the past few years later have the following results:

A. The knife has been previously abused to the point it is out of spec as reported by the manufacturer after being returned to the manufacturer.
B. The person who did the test refused to send the knife in. (Probably because of A.)


My thoughts are: Knives require some maintenance. Knives will eventually wear out. The first time the lock slips, I am going to send it to the manufacturer or replace it.

 

[mqqn]

Sarcasm never proves a point, it just degrades the conversation.

The slipjoint is an entirely different design. It has a safety detent spring to keep the blade open.

Try opening that slipjoint with one hand. Try taking the safety detent spring out and see how useful the knife becomes.

The locking knife has huge advantages over the slipjoint: it allows easy, one-handed opening and it allows a very large blade to be used safely. If you don't like the lock on a locking folder, what are you going to replace it with? A detent spring? Are you just going to let the blade swing freely? Comparing a slipjoint to a locking folder is like comparing a slipjoint to a fixed blade. They are very different.

The point is that you are using a knife to cut. If you have to rely on a locking mechanism to keep you from being injured, maybe you are in the wrong hobby.

best

mqqn

 

[Twindog]

Just answer the last paragraph in my post.

 

[B.F.U]

A liner lock or a frame lock can be excellent and robust. The Spyderco Military's imbedded liner lock is excellent. The Sebenza's frame lock is awesome. If you took the time to watch the videos that Marthinus provided you'd see that a cheap Swiss Army knife's liner lock easily took powerful blows and did not fail.


A lockback can be poorly fitted or poorly designed and fail easily. Any of these locks can be well made and well designed -- or vice versa. Design, materials and assembly matter.

I agree. I wasn't saying liner/frame locks are always bad, or that lockbacks etc. are always good. But I would contend that a perfectly executed backlock etc would be more desirable than a perfectly executed linerlock etc because it is a better DESIGN.

 

[B.F.U]

This is common sense folks. Study It. Learn From it.

I'm bad at recognizing sarcasm. If you are being genuine, thanks! If not... well... ok.