Lock failure

S

Swedge

Joined
Dec 23, 2008
Messages
334
We all know that folding knives with locks that fix the blade in place are safer than slip joints, which rely on spring pressure to keep the blade open. That is certainly true in theory. But how about in practice?

Has anyone here had a personal experience with a slip joint where the failure to have a lock keeping the blade open caused an injury?

Or with another lock mechanism that failed and actually caused injury?

Not "I heard about this guy once." Something that happened to you or you witnessed or someone you could rely on telling you what happened to him or what he saw.

If so, particulars please.
 
I have managed to cut my right index finger a couple of times by improper use of a folding knife, causing it to fold up while in use. The knives in use were non-locking folders. That I managed to screw up twice in the same way merely indicates that I can be a slow learner. That the last time it happened was over twenty years ago indicates that I do learn eventually.

I've said it before, and I'll say it again. Locks are designed to lull you into a false sense of security. They try to make you forget that the knife you are using is designed to fold up. The more you trust the lock, the worse you are going to get hurt when it finally fails to protect you from your own bad habits.
 
I question how it can happen, but I'm sure it can. The way I see it, if you put any pressure on the actual cutting edge, that pressure is in the opposite direction of the locking mechanism, which means that pressure *should* keep the blade open.

The only method I can see that can cause a blade to go down on flesh is if you tried to stab something and then pushed the blade upwards, which would apply pressure in the same direction as the blade path.

Of course, I'm not that stupid. ;)

I have managed to disengage the lock bar on a liner lock because of having big hands. However, the blade stayed open because of a finger choil as well as, more importantly, that I was actually using the blade edge to cut.

EDIT: Damnit, Blade Affi! You said what I said in a single sentence. :(
 
Back when I was five years old and got my first SAK I closed the knife on my finger. For the longest time afterward I avoided them, but now I've grown to like a good slip joint. It adds a little more risk to a normally dull and safe world.
 
Well, for light cutting, a slipjoint is fine...but for anything more serious... wouldnt take the chance.

What you say about the pressure works in theory and assuming the user makes no mistakes. However, accidents and mistakes happen to everyone, and the stronger the lock the less chance of cutting yourself or losing your fingers.
 
I don't recall ever cutting myself due to lock failure since I practice proper knife handling. However, there's been a few times where I was closing the blades on SAK's where I would snip my fingers by accident :o
 
By way of clarification, I'm not asking about closing the knife on your fingers when you're actually trying to close it. That can happen with many knives with locks. I'm wondering about the incidence of slip joints injuring the user in use by reason of not having a lock. Or other knives that do have locks that fail in use.
 
The two most memorable were an 806 closing on my index finger while digging in a creek/river bed and a Military closing on my index finger on another trip to the same place. Bad Karma.

Figure something pushed the axis bar back - a lot of sand, pebbles, etc. One reason I kinda like the new CBL being a bit strong in operation.

As to the Military, FOD issue I figure. Really had other things on my mind than figure out the "why".

A recent nasty is due to a UKPK - the tip position is "below the x-axis" and the knife folded on me while opening a 2.5 gallon "protein powder" bucket. So many knives around and I use a slippy - what was I thinking.

I've had other locks fail, usually during stabbing moves or when "jerk" (back and forth, sawing motions) cutting thick material. I usually only remember particulars when a scar is noticed or I pick up a knife that has failed. Cardboard boxes should have a label warning of the danger, as should plastic containers.

Liner locks, a design I no longer recommend, seem to be the most failure prone, followed by lockbacks. These are also the most prevelant lock designs I believe for knives in general.

This last Tuesday personally witnessed my superior get a nasty cut from a Buck liner-lock knife while opening a blister pack. Don't know the model - it was bluish in color. I laughed too much, I guess - he really lit up the skies verbally - he has been gifted a nice mini-Grip. We had had discussions concerning locks and reliability/strength.
 
orthogonal1 said:
The two most memorable were an 806 closing on my index finger while digging in a creek/river bed and a Military closing on my index finger on another trip to the same place.
Click to expand...

Did this involve pushing the knife back and forth? It is that the tip was into the creek/river bed?
 
Swedge said:
Did this involve pushing the knife back and forth? It is that the tip was into the creek/river bed?
Click to expand...


Yep, I was digging for my car keys in the bed. In and out, side to side, etc. My hands were numb from the cold water, and I was irked pretty bad, so I didn't even realize I was cut for a time.
 
Swedge said:
Has anyone here had a personal experience with a slip joint where the failure to have a lock keeping the blade open caused an injury?

SNIP

Or with another lock mechanism that failed and actually caused injury?

If so, particulars please.
Click to expand...

Many years ago I used to carry a Case Stockman in my tool bags. It was almost the perfect knife; I could use the large blade for utility work, and the smaller ones to sharpen carpentry pencils, cut veneers, mark wood for precise cuts, etc.

One day I was trying to dig out the wood around a bent nail. The last lick bent the nail over and I was trying to get enough wood from around the nail to get my nail digger in to remove it. It was a tough piece of wood, and I was working overhead standing on a scaffold about 20 feet in the air where I couldn't get a lot of leverage.

I got impatient, stupid, and sloppy. I dug in hard with the blade, twisted the knife just a little the wrong way and it closed with me pushing hard on it. It cut to the bone very easily. (Nothing like a sharp knife!) This was total operator error. Over the years when I have been bitten by a slipjoint (many times), it has been 100% my fault.

That being said, I look at a locking blade knife as no more than a slipjoint with a safety latch on it. Using a locker with that concept in mind, through all my locking blade types, I have never been cut while using the knife if my hand stayed on the handle. I can't blame the knife if I am dripping with sweat and my hand slips across the blade!

All of my work knives lock with some system of another now, and I won't use a slipjoint for really hard work again. Almost without exception, when I examine a locker that has failed, it has been for obvious reasons. Crappy design, a poorly made (cheapie) knife, weak lock design, pushing the knife too hard, or the most prevalent reason seems to be dirt, pocket lint or other debris in the mechanism.

Robert
 
I was just a kid, but was trying to dig something out of a piece of wood with the tip of my SAK when it closed on my finger as I rotated the knife. Stupid mistake, almost cut my finger completely off at the knuckle. Lock would have prevented that. To this day, I can only purchase and carry locking knives.
 
My Dad says back in the time before locking blades were widely available, it was common to get cut if a user was trying to use the tip to start a hole in some sort of tough material.
 
When I was in Scouts lots of kids had a range of injuries from their knives folding over on them. Mostly from stabbing stuff or prying. Improper use of a knife will always lead to getting hurt.
 
All I carry atm are slipjoints, I've never had one close on me, unless you're stabbing or cutting with the spine, I don't see how you're going to unlock the knife(but I've heard of people having the knife get wedged in wood and when pulling the knife back, the blade unlocked).
 
I seem to cut myself more often with folders that have locking mechanisms than slipjoints. Perhaps it has something to do with knowing that the knife I'm using doesn't have training wheels and won't protect me if I'm careless. Could be that most of the slipjoints I have glide through most materials like it's not even there.

Either way, most cutting accidents usually occur when I'm sharpening. My left index finger seems to always have a nice, clean cut. Gotta invest in some proper stones.
 
I use to carve a lot when I was younger. I used a SAK because it had a nice thin blade and was cheap (a gift actually). I was carving a walking stick out of a red alder. ANyways, as I was carving and pulled the knife back I hit a knot (i didnt lift the knife high enough and it just caught on the blade. This cause the knife to close on my fingers. I was cut pretty good but nothing serious. A lock would have easily prevented this as it wasnt a lot of force to cause the closure. A mistake on my part but it happens.
 
I've carried slip joints most all my life, and I've never got bit once I cut myself once or twine when I was a little kid and doing something stupid.

On the other hand, twice in my life, I've seen first hand disasterous after effects of thinking a lock meant ignore basic safty.

One was back in the 80's when I was a machinist at the Watkins-Johnson company. We were doing a job that involved making some cutouts in some sheets of material that was like what they made pickup bed liners. This one young guy had a Buck 110, and was driving his knife thru the material and then with the point stuck in, he'd push down using the blade as a pivot and cut the thin plastic. We, some of the older guys, warned him not to do that, that he was going to get hurt. Smart ass kid remarked that us old guys with our old fashioned knives didn't understand. Right.

About an hour after lunch, his lock broke loose, folded up from the presure he was putting on his knife, and amputated his right index finger at the second joint. Cut deep into the middle finger. EMT's took him and finger, which our shop forman put in a cup of ice from the caffeteria, and he got it put back on. It sort of worked halfway decent afterward. His faith got a little shaken in locks that day.

Second time was a year ago. Last winter I had to have my left thumb operated on for a tendon problem. While I was in the waiting room of the doctor that was a hand specialist, a young guy and his mother were sitting opposite me, with the kid's hand bandaged up. In small talk, found out he was playing around with a tactical style knife in the woods in back of his house, doing some heavy cutting, and the lock let go. Damaged the tendons in his right index finger, and they were going to operate on it to see if they could re-attach everything and get it back to working. Bad cut, numb dead feeling finger.

I think locks are a false sense of security. if I need a knife that won't fold on me, I use a sheath knife. I guess millions of scandinavians can't be wrong; they use puukos for most things over there, and I've gotten into pocket fixed blades myself. My sak's and other slip joint pocket knives are for light everyday use. For heavier cutting, I go with a small fixed blade. I feel safer with small puukos like a Bruselleto Baldor or Helle Nying in my pocket, than any locking blade contraption. Ragnars has a good selection of them.

I feel locking blade knives are an accident waiting to happen due to over confidence. Like some people depending on firearm safetys. Dirt, wear, can make something fail. Why chance it?
 
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