importance of locks

Danzz said:
So not doubtlessly the strongest folder, but a solid contender.
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True, a good bali is quite strong, but I think in terms of sheer static strength, there are other folders that are at least as strong, or even stronger. Take a look at the pivot pin and frame lock thickness on a Strider: so long as that lock stays engaged, it'll take a lot more stress than any balisong.

You make a good point about the handles. I hadn't thought about it before, but even if the stop pin sheared, the twin pivots act as a failsafe. Neat. :D
 
I'm going to go ahead and say that balis are the strongest folders. Throw that opinion out there. I trust my 41MC big time. And of course, despite D2 steel and titanium handles, it's wayyyy cheaper than the conventional super tough folders. Very cool.

Got sort of annoyed with the lock conversation though. I trust my locks, after testing them, with some basic safety precautions. I decided to go out and buy a small fixed blade today and go ahead and let that make my point. Yeah, a folder advertised to have a super tough lock had better deliver (and don't cut me down on semantics here. Tough in every way), but a 20 dollar neck knife can compete head to head with the strongest folders. So now I'm carrying my CRKT STIFF KISS.
 
It's driving me nuts, I *know* I've seen photos of a couple folding double-edge knives (customs, probably), but can't remember where I saw 'em... :confused:[/QUOTE]


one of the few i have ever seen is the gerber applegate FWIW, IIRC some even have a sharpened "false" edge from gerber.
 
Artfully Martial said:
I'm going to go ahead and say that balis are the strongest folders. Throw that opinion out there. I trust my 41MC big time. And of course, despite D2 steel and titanium handles, it's wayyyy cheaper than the conventional super tough folders. Very cool.

Got sort of annoyed with the lock conversation though. I trust my locks, after testing them, with some basic safety precautions. I decided to go out and buy a small fixed blade today and go ahead and let that make my point. Yeah, a folder advertised to have a super tough lock had better deliver (and don't cut me down on semantics here. Tough in every way), but a 20 dollar neck knife can compete head to head with the strongest folders. So now I'm carrying my CRKT STIFF KISS.
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I think the above comments are the most intellegent in this whole overlong thread.
 
I agree with jackknife and A.M. all the way. If you want the strongest lock get a fixed blade. There near impossible to close on your hand so there ya go :p
 
Locks are not very important on folders, but when it comes to keeping a knife open, I'll only take either a slipjoint or a VERY good lock (Axis). The reason is that cheap locks can get the user too confident and then the knife starts getting used like it needs a lock (twisting, digging, prying, stabbing etc) and that's how fingers get lost ;) I've never had a SAK or any other slipjoint close on me, so locks are not that important. For those times when I need something that won't fold, I use a fixed blade. But really, I think that if people considered how often they really get saved by a lock they would be surprised, and slipjoints teach some responsibility :D
 
STR said:
Speaking of warranty coverage lets look at a few tid bits from some of the more popular makers of tactical folders that are considered to have both a strong fan base of supporters and strong locks.

Just some partial pastes here and not the whole warranty of course.

Warranty review

Spyderco says;
For the following repairs, please include $20.00 plus $5.00 shipping and handling:
Blade or Edge -- broken tip from prying or dropping, destroyed edge due to improper sharpening, loose blade from abuse, rust due to neglect or other blade issues. (Spyderco is unable to replace blades in most models)

Spyderco knives are designed and built for use as cutting tools. Use of our knives for any purpose other than cutting is considered abuse. As with any usable tool, Spyderco knives can wear out. They may also fail to perform if not used or cared for properly. If your knife has been put to hard use for a long period of time it is possible that Spyderco will not be able to improve the condition of your knife.


Cold Steel says;

The Cold Steel Warranty covers our products when they are used as they were intended to be used. For example, do not use your knife as a pry bar, axe, chisel, screwdriver, or saw.

Bench Made says;

Do not use your new knife as a screwdriver, prybar, chisel, or punch. Do not throw your knife or use it for any purpose other than cutting. Do not disassemble your knife. Do not sharpen your knife on a power grinding wheel.
Any of these acts will void your warranty.

Emerson says;

Your Emerson knife is built to withstand the rigors of extreme use, but it is a knife, not a chisel, screwdriver or hammer, and it is not intended for use as such. This knife is a cutting tool and is not designed for throwing. Do not use it in that capacity.


That is just from the four big ones that I happen to buy a lot of. I believe the Ritter knife mentioned by Cliff is made by BenchMade so it would fall into this warranty. I venture to say that none of the major manufacturers will agree that prying is considered within the normal parameters of knife usage.
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Amen Brother! This says it all.

It is probably straight from the manufacturer's product liability attorney's mouth, IMHO. Hee hee!
 
WarRaven said:
Oh hey, want another suggestion to cure bleeding like that out on the road?

When ever i hammer my fingers with something, like a hammer or such(Mechanic by trade) and you get them nasty blood pockets under your nails or a real bad cut that you cant sew or deal with asap, try this....

This is not for the faint of heart either but it works well, break the glass on a tail light bulb, the bulb itself not the lens cover. :D

Then twist the wires together into a point, position your injury next to it with pressure an have someone apply the brake lights, the tungsten element without argon to repel the electrons allows it to go white hot, which in turn will burn through a fingernail or seal a bleeder up like the cats pajamas.
Each bulb will only last a few seconds without the argon, but is is more then enough to seal or open you up, depending on your need at hand.

Sorry O/T i know,just thought i'd throw it out there, may help someone one day.

Peace

WR
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Is that really true? I want to see the video! Maybe we need a new forum, "Knife Injuries-Causes and Cures".
 
STR said:
Joe pointed out that if you imagine a knife stuck in something after a thrust and you pulled it out and in the rigor of a fight or from fast movement you snapped it back by pulling it hard out of whatever it was stuck in and gave it a good tap on something behind you how that is a 'real world' situation.
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When I said stabs/thrusts could load the lock I didn't mean on the draw out, I meant on the entry which is why I noted the off-perpendicular loading, if you consider moving targets this pretty much a gauranteed result even with perfect technique. The load is not going to be 100% compressive, there will be a percentage loaded either against the edge or spine depending on the exact vector. This is why you can trivially fold a slipjoint if you stabb it very hard into a piece of wood. It is why this is one of the performance attributes (tip penetration) that I take a lot of precautions with with folders.

Dropping it or loosing it and having it fly out of your hand or knocked out by an opponent and hitting the hardwood floor or a sheetrocked wall is a more real life test than the spine whack.
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It won't get knocked out of your hand, any normal man can easily keep a folding knife in hand under impacts which will break the blade let alone effect any lock, I have done it myself and also had others hold the knife. The only problem I had was whem my brother missed and "accidently" smashed me right across the wrist. This was hashed out years ago when someone brought it up for the same reason.

How many whacks before it is beyond what the folders lock is supposed to be able to endure?
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It would depend on what it is being promoted to do and the nature of the blade obviously.

You would not expect the lock on the Calypso Jr. to be similar to the ER Fulcrum in regards to strength/toughness because the knives are meant to be used for different tasks. Ritter has promoted his knife to be used for batoning in regards to survival so it is rather obvious that a lot of impacts are necessary for that.

One of the main points of contention was clearified by Steve Harvey many years ago where he noted that there is a big difference between breaking a lock and causing it to release, this is a point that people still miss, it is the latter behavior that is the problem. Very rarely, if ever do people talk about broken locks, releases are the issue.

This is a lock disengaging without damage, or little damage at all, which then returns to functioning. In many other products, as noted in the above, this would never be tolerated with the frequency it is seen with knives especially given how they are constantly promoted for tactical and other extreme use. I am still amazed someone has not been sued yet given what they do sue for all the time.

Artfully Martial said:
... but a 20 dollar neck knife can compete head to head with the strongest folders. So now I'm carrying my CRKT STIFF KISS.
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There are lots of folders far stronger than that knife. In general yes fixed blades are less prone to that type of failure, they are also more ergonomic, much cheaper, easier to clean and sharpen, and in general offer superior performance. The only reason you carry folders is because you can't carry a fixed blade so the arguement as to "just carry a fixed blade" is not valid, nor is it necessary, you can just carry a suitable lock, they do exist, lots of knives will break through the blade before the lock gives so they would do no better as a fixed blade.

Joe Talmadge said:
......seem to be a walk in the park compared to shearing a big hardened S30V locking lug through the 1/8" hardened S30V frame.
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Yeah buy you can break it under impact as S30V isn't that tough fracture wise, I did it to one - I was doing static blocks against a mild steel bar, fairly heavy work, and it took repeated impacts. Based on work I did with the Chinook, it is actually better able to handle such impacts. Of course you can also break the blade with such impacts given it is made out of the same material as the lock.

-Cliff
 
You know it almost sounds like if I just design a lock for the lock on a lock back and mid locking folders that it would keep the lock bar from lifting up when it was whacked.

This would have to be something like a safety you could activate for the lock bar much like the one that is on the frame locks or the LAWKS system only for a lock bar.

Then it would like double locked which should hook it down but good if it could be designed properly. I may have to sit down and play with that idea some.

STR
 
Who is "ER" and why is it not being licensed by locking folder makers if the idea is already out there? Is that the "Dawg ugly" knife you showed me that time Cliff? Tell me more. That solves the problem if it is what I'm talking about.
 
Leverage!

The big issue is that the blade is secured in a limited space near the pivot and the blade and handle are a lot longer than the distance between the pivot and the things securing the blade. With a short blade and handle the leaverage mechanical advantage working against the securing devices is like 6-to-1. With longer blades it is more like 12-to-1. If you apply a hundred pounds of pressure near the tip of a long folding blade the result can be more than a thousand pounds of pressure on the lock or the pivot. As knives have gotten bigger and heavier the leverage and the pressure have gone up.

A long blade also increases the leverage trying to nip off your fingers if the lock fails. A long and heavy serrated blade will perforate your fingers pretty well if it just swings closed without force behind the blade.

Your old boy scout knife with a 2.5-inch blade could get by with just back-spring pressure for security. When you move up to a 4" blade that is twice as thick you start to get new problems. Just whittling with the longer/thicker blade is likely to get you cut. You slice into a stick and get the blade wedged in the cut about 3 inches out from the pivot. You pull the blade out of the cut and it sticks in the cut and closes on your fingers. If you pulled it out hard you could get a real cut. This is less likely to happen and the cut is smaller with the 2.5-inch blade.
 
Extrema Ratio, it hasn't caught on probably because the knives don't get much discussion as they are not really knives as much as sharpened pokers, the Fulcrum has a thicker cross section than the HOFSH for example so it is beyond silly for a small folder. The handle is also squarish and makes Strider's grips look ergonomic in comparison.

-Cliff
 
Cliff Stamp said:
One of the main points of contention was clearified by Steve Harvey many years ago where he noted that there is a big difference between breaking a lock and causing it to release, this is a point that people still miss, it is the latter behavior that is the problem. Very rarely, if ever do people talk about broken locks, releases are the issue.
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Sounds familiar. Basically the same thing I was talking about, strength (breaking a lock) vs. security (causing it to release).

No wonder knife companies harp on the strength of their locks, most customers don't understand the distinction.
 
DGG said:
Is that really true? I want to see the video! Maybe we need a new forum, "Knife Injuries-Causes and Cures".
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Lmao,
Almost forgot about this, seen your quote and near spewed my cola

Yeah it is friend, today the stage was set,

On it we had the Victim,(Buddy)
The Vehicle with suspect bulb socket,
and a random peep inside working on dash.

Theres me, i was buttin a smoke whilst watching buddy shake this tailight only light with the park lights on, and he's watching it dim an grow brighter as he shook it near the van's door.

I said to him,its not the bulb but the socket, he says, BS and wicks it harder this time striking the open van door edge breaking the bulbs glass, an still lit on park, but gettin white near open flame,(Least resistance,no cooling,amperage applied=Fire) and he says crap, throws a cloth on it,then realizes thats a bad idea an grabs it, only as other buddy inside gets excited by the commotion going on at the rear, hits the brake on the way out,lighting second element,the hotter one lol.

This easily burns through the rag,into buddy's finger an thumb tips, leavin the air lingering of bacon an me an 3 other people howling our collective asss's off.

Buddy is ok, only went about a 1/4 in deep, no blood though :D

Bad timing, outside influence, an a bad shake an grab.

My other friends in the same trade, use wire an a torch, i find that harder to deal with myself.

I Myself discovered it the hard way, changing bulbs on a school bus eons ago,
(Park element was out,brake good)but was stuck, an squeezed too hard as i twisted,opening me up as lady inside bus,cleaning,hits the brake.
No bandaid was needed.

I would have prefered crazy glue to that. :D


Another thing since im so off topic, when you guys talk about chisel grinds, all i can think about in my mind, is fresh Engine block an Head edges, these buggers can be hell to one unsuspecting of thier relative sharpness, near lost my right index knuckle to one i pulled the deck plate of off after i opened up the bore some on a small block. :D

Love my knives, but them edges an coffee can lids, makes my skin crawl lol

Hhmmmm,Wonder if Cliff S, has included the ole coffee can lid in any of his cutting tests...?

Sorry bout the o/t thing all, just thought i'd share a personal giggle with yas :p
 
the secondary lock on the ER series due to its placement isnt something ya re gonna be able to engage very fast, oh it works fine imho, but as far as drawing the knife/deploying/engage safety all real fast -isnt gonna happen.

mine likes to slide over the wrong way and lock the thing up too if i dont pay any attention to it - ie the blade wont deploy or open if the lock is locked and the blade is not open.

so, though a good idea i guess it does have cons, ya have to be aware of them.

imho the ER folders are probably the toughest around, bar none, as far as lock strength, i cant imagine one failing/breaking myself..
 
SIFU1A said:
... mine likes to slide over the wrong way and lock the thing up too if i dont pay any attention to it - ie the blade wont deploy or open if the lock is locked and the blade is not open.
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The one on mine is fairly solid and doesn't move unless I flip it, interesting that it can be locked closed though, might make it attractive to some.

-Cliff
 
A lock on a knife is put there to give the user a greater degree of safety (than a slip-joint or no lock at all) from the blade closing on the users hand.

Strength of the lock and reliability of the lock are two different questions. Naturally a manufacturer or custom maker would want to try to provide the greatest degree of both strength and reliability into each lock.

Spyderco has been spine-striking their folders since 1981. A light but firm tap on a hard surface with the back of the tip is a good test for reliability. If there is a problem in geometry, heat treat, or interface engagement, the strike will show it. Making safe knives is the manufcturers responsibility.

This is also true of knives that are used. They get dirt, lint, grease, chips, etc. in them. It is the users responsibility to keep his/her knife clean, sharp and safe.

Spyderco breaks a lot of product, we have our own "in-house" standards for strength that we must meet. I would guess that most responsibile knife companies have their own methods of testing for safety.

When the lock fails, it is going to be a slip (defeat, release, etc) or a material failure (pin. tang, handle, lock, etc.)

Every lock design has its own weak points. These weak points are greatly diminished when responsible manufacturers build their product with care and concern for safety. Any lock with an incorrect geometry (eg: wrong angle on the interface) will fail.

Putting a pin through the lock bar is of little use if the geometry of the interface is off. A lock is more of a system and all parts must work together.

When we heard that one person had defeated 2 Manix and a Chinook, we naturally needed to see them and they are on the way. In addition, the person that had the problem is going to work with us to see what happened.

The only way that I can think of that the lock was defeated was by hitting the block so hard that the lock itself was knocked out of the tang.

We wack them pretty hard during the mfg process, so it would take a full force full leverage slam to do it, if it can be done. He said he hit the table very hard and held the knife at the lanyard end (full leverage).

Unrealistic to do, but it's still something that we need to look at. If we can reproduce the effect, we'll figure out a way to improve it. Maybe it's a stonger spring, maybe it's lightening the lock bar (without losing strength). Whatever it is (assuming it's not just incorrect geometry), we want to know.

The Chinook / Manix is in our opinion one of the strongest most reliable lockbacks there is. But everything can be improved. The Chinook 2 is an improvement over the original Chinook.

sal
 
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