Folder Lock: Safety device or something else entirely?

[NeilB]

This ignores the entire purpose of the "design feature", i.e. safety.

I disagree. Not all design features are primarily about safety. Some are about maintainability. Some are about durability. Some are about rapid deployment. And some are about safety.

It is not merely an 'implication', it is the sole purpose of the feature's invention and implementation.

Again, I disagree. If we are talking the locking bar, it has other functions than "safety" that are more related to durability as well as structural integrity. Perhaps these are difficult distinctions for those who do not work as engineers, but they are how your products are actually designed.

A liner-lock which does not prevent the blade from closing when force is applied from the spine (or in that direction) is NOT a blade "lock" of any sort and serves no apparent purpose in the design other than appearance, despite it having been invented specifically for safety. It is then a "false" lock, much like a "false edge" which is left unsharpened so as not to cut.

I hate disagreeing with you this much, but my lock bar does seem to prevent the blade from closing on my fingers when I'm wiggling the point through some thick cardboard and the pressure on the blade comes from the spine and not the cutting edge. Is it something I'd bet my life on? No, of course not. Then again, I don't bet my life on the thumb safety on my 1911 either. That's only common sense, I think. I am specifically excluding "spine whacks" here.

There is no confusion, only denial. The lock-bar on a liner-lock is NOT a "significant part of the structural package".

We'll just have to disagree, then. I'm OK with that.

One might argue that the blade-stop which prevents the knife from folding backwards during use is a significant structural component...

Thank goodness! I agree with that. The blade stop IS a significant structural feature for the reason you outlined.

A locking OPINEL qualifies as 'hard use' over any knife with a 'false lock' (i.e. liner that does not prevent blade from closing).

Now, you're just being contrary.

 

[chiral.grolim]

I disagree. Not all design features are primarily about safety...

I never typed "all design features".

Again, I disagree. If we are talking the locking bar, it has other functions than "safety" that are more related to durability as well as structural integrity...

As i already made clear, a folder without a lock is still a durable, structurally sound cutting tool. All of my folders work just as well when cutting with the edge without their locks, they are simply less safe. Look up the patent information on each lock design, each were invented for safety primarily if not exclusively. Look into the history of Opinel - they didn't implement any sort of lock until quite recently but the knives were structurally sound. It should not be a point of contention, as this thread obviates.

I hate disagreeing with you this much, but my lock bar does seem to prevent the blade from closing on my fingers w...

No disagreement, i stated:

A liner lock which does not prevent the blade from closing ... is NOT a blade "lock" of any sort...

Yours DOES prevent it from closing, therefore it is not NOT a "lock". Where's the problem?

Thank goodness! I agree with that. The blade stop IS a significant structural feature for the reason you outlined.

Indeed

 

[singularity35]

Takes convoluted logic to try to show that a feature that will prevent cuts, is not a safety feature.

Seems simple to me. Prevents injury=safety feature.

 

[NeilB]

There are many, many structural features which are arguably "safer" than other structural features. The vast majority of those features were adopted primarily due to savings in cost and weight, not because "Zowie! This saves lives!" As unfortunate as that may be. For example steel core construction is favored in skyscraper construction over dry laid stone pyramids because of weight and cost.

Also, if your knife is perfectly functional without the liner lock, why don't you remove it? I mean, you say it doesn't add any safety, so why bother?

 

[singularity35]

There are many, many structural features which are arguably "safer" than other structural features. The vast majority of those features were adopted primarily due to savings in cost and weight, not because "Zowie! This saves lives!" As unfortunate as that may be. For example steel core construction is favored in skyscraper construction over dry laid stone pyramids because of weight and cost.

Also, if your knife is perfectly functional without the liner lock, why don't you remove it? I mean, you say it doesn't add any safety, so why bother?

If a design feature that will allow you to save money and at the same time be safer then Zowie! It's a safety feature that additionally will save you money. Total win and very simple!

 

[pinnah]

Takes convoluted logic to try to show that a feature that will prevent cuts, is not a safety feature.

Seems simple to me. Prevents injury=safety feature.

Risk decisions are pretty squirely and very prone to unexpected consequences.

The effect of mandated bicycle helmets is level or increased head injuries per capita. Mandatory helmet use drives down ridership. Lower ridership leads to higher (not lower, but higher) rates of car/bike collisions, which drives up rates of head injuries among the few remaining riders.

In skiing, helmet use is collated to higher average skier speed and the same or higher rates of head injury related to the higher speeds.

With knives, locks can lead users to attempt to use the knife as a lever, leading to catastrophic closure if/when the lock fails.

You should look up the article on Wikipedia about risk compensation that I posted on page 2 of this thread.

Use the lock. Treat the knife like a slip joint.

 

[Karda]

Risk decisions are pretty squirely and very prone to unexpected consequences.

The effect of mandated bicycle helmets is level or increased head injuries per capita. Mandatory helmet use drives down ridership. Lower ridership leads to higher (not lower, but higher) rates of car/bike collisions, which drives up rates of head injuries among the few remaining riders.

In skiing, helmet use is collated to higher average skier speed and the same or higher rates of head injury related to the higher speeds.

With knives, locks can lead users to attempt to use the knife as a lever, leading to catastrophic closure if/when the lock fails.

You should look up the article on Wikipedia about risk compensation that I posted on page 2 of this thread.

Use the lock. Treat the knife like a slip joint.

Well said, pinnah!
Some people would rather argue than understand......

 

[chiral.grolim]

Also, if your knife is perfectly functional without the liner lock, why don't you remove it? I mean, you say it doesn't add any safety, so why bother?

LOL! Please go back and read my posts. Specifically the statement i just quoted above but will repeat here:

A liner lock which does not prevent the blade from closing ... is NOT a blade "lock" of any sort...

For a quick lesson in English, the above statement is "If/Then" - IF your liner lock does not prevent the blade from closing THEN it is not a "lock". It so happens I still own only one liner-lock knife, BM745 Mini-Dejavoo, and it DOES pass the spine-whack test and DOES prevent the blade from closing under normal use that includes force directed against the spine, ergo it is a "lock". But knives I've previously owned and those discussed in this thread do NOT perform as well, ergo they are NOT locks...
...and rather than get rid of the liner 'lock' on those, i simply stopped using the knife for most of my cutting chores for my own safety

 

[Czechmate]

A lock is not a knife safety device?

 

[singularity35]

Risk decisions are pretty squirely and very prone to unexpected consequences.

The effect of mandated bicycle helmets is level or increased head injuries per capita. Mandatory helmet use drives down ridership. Lower ridership leads to higher (not lower, but higher) rates of car/bike collisions, which drives up rates of head injuries among the few remaining riders.

In skiing, helmet use is collated to higher average skier speed and the same or higher rates of head injury related to the higher speeds.

With knives, locks can lead users to attempt to use the knife as a lever, leading to catastrophic closure if/when the lock fails.

You should look up the article on Wikipedia about risk compensation that I posted on page 2 of this thread.

Use the lock. Treat the knife like a slip joint.

There we have the fundamental difference in the two camps in this thread. One camp looks at locks as a design feature. The other camp looks at locks and other safety devices as behavior altering devices.

 

[OrdnanceBubbaUSMC]

If a good, strong lock mechanism causes people to be unsafe with a knife, wouldn't a fixed blade up the anti much more? It is just poor logic all the way around.

Learning knife use and testing procedures from videos is a whole different topic.

 

[singularity35]

If a good, strong lock mechanism causes people to be unsafe with a knife, wouldn't a fixed blade up the anti much more? It is just poor logic all the way around.

Learning knife use and testing procedures from videos is a whole different topic.

That there is pretty well said.

 

[dewildeman]

I like the description that a safety is a mechanical device that can fail.

 

[Karda]

I think the confusion comes from the usage of the term "lock" in bother liner and frame.
It isn't actually a "lock", as it doesn't "lock" the blade in an open position, it "holds" the blade in the open position. It was never meant to be a failsafe against accidental closure. When it was designed, and now, it was assumed that the user would have sense enough to use the knife with forethought and in a safe manner.

 

[OrdnanceBubbaUSMC]

I think the confusion comes from the usage of the term "lock" in bother liner and frame.
It isn't actually a "lock", as it doesn't "lock" the blade in an open position, it "holds" the blade in the open position. It was never meant to be a failsafe against accidental closure. When it was designed, and now, it was assumed that the user would have sense enough to use the knife with forethought and in a safe manner.

That sounds good but ideally it will hold the blade in the open position as reliably and assuredly as possible until you activate the release. The more stresses, accidents, pressures, etc. it can withstand the better - assuming size, weight, and operation isn't awful as compromise.

It only adds to the versatility, safety, yada yada if the lock/hold mechanism is as reliable and strong as possible.

 

[Insipid Moniker]

I think the confusion comes from the usage of the term "lock" in bother liner and frame.
It isn't actually a "lock", as it doesn't "lock" the blade in an open position, it "holds" the blade in the open position. It was never meant to be a failsafe against accidental closure. When it was designed, and now, it was assumed that the user would have sense enough to use the knife with forethought and in a safe manner.

Honestly, I think this is a bit of historical revisionism. The first locks were developed well after things like the friction folder, which holds a knife open perfectly well. And most early lock designs made a knife less convenient to open and close, and in more modern times the safety and strength aspects of knife locks have certainly come to the forefront. What you say may have been true of the original liner lock designs, but many of the changes and refinements Michael Walker made to the mechanism were explicitly to improve it's strength and safety.

In short, I sincerely doubt that any modern knife maker or designer would agree that a lock is purely to hold the blade open and not to prevent accidental closure. Perhaps I am wrong about that, but there certainly seems to be evidence to the contrary.