Battle of the Locks

Snick,

The Achilles heel of the clasp-lock is the hole in the leaf-spring that the tang protrusion sits in. This must be a precise fit or the blade has vertical play. Any stress will tend to deform this hole or peen the front of it, allowing play to develop. And stress is massive, when you consider that the size of many Navajas allows much greater leverage to be applied than that on the average 4" folder. A very hard, thick leaf spring might fix this, I'm just pointing it out.

All,

I'm going to try the road less-travelled and say my favorite is the basic liner-lock. I agree with Mr. Talmadge 100% when he says that strength is not the issue - any of the locks mentioned, if well-made, will withstand more force than a user could reasonably apply. I'm thrilled with the figures on the Axis-lock and Rolling-Lock, but 10x as strong as I might possibly need is no better to me than 3x as strong.

Again, I agree with Mr. Talmadge that reliability is the issue, and I concede that many folks can cause failure of linerlocks with certain grips (all hands are different). I simply can't, not on the ones I carry. If I find a liner-lock that I can disengage with certain grips, by torquing, or by spine-whack, I don't buy that knife. Seems like the liner-lock might be a craps-shoot depending on your hands and its manufacture, but when it works, it works so well.

Lockbacks may also be disengaged by some with a strong grip, and some fail a moderate spine-whack. They also require more force to open and are hard to close with one hand.

The Axis lock is brilliant, but still requires a bit of force to open and the one-handed closing is awkward because the lock doesn't like to be pulled back by only one side's stud. I can pull on both, but I ave to change my grip.

The Rolling Lock? I haven't seen one since they had the awful front-release. I hear a lot about gritty actions, but if this smooths out with wear, these seem excellent.

The integral lock I like for the same reasons I like the liner-lock (and the distinction is vague between the two): smooth, light action and easy one-handed closing. IMO, the extra strength is worth nothing to me, I have no trouble with accidental disengagement on most "normal" linerlocks, and the integral lock is unattractive in comparison. Elishewitz's bolster-lock modification looks better, but I am very concerned about the pinch-point created when the kife closes and the bolster moves to meet the scale.

I guess what I'm saying is that these all work well, but given my druthers I'll still take a well-made linerlock over anything else for its combination of smooth opening, easy one-handed closing, and general beauty. I don't advocate choosing form over funtion, but when things all function well, as I feel these do, we are allowed the freedom to choose by more subtle qualities.

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-Drew Gleason
Little Bear Knives
 
My favorite would have to be the button lock. It seems curious to me that no one even mentioned this one yet. This lock is currently found on the Speed-Tech manual action knives and loads of autos. It is easily one hand operated and seems to me to be as strong as any other lock. (I have never heard of an auto with this style of lock failing.) The chance of dirt fouling seems less than for the axis or rolling lock as there are less parts exposed and even if dirt got in the mechanism it would be pushed away by the locks action.
 
Just a quick FYI, all the Axis locks I've handled love to be closed with one hand, and do just fine if you pull the lock back with just one button. That's how I close my axis exclusively, and it works wonderfully. Wonder if you just handled a bad one?

joe
 
On the issue of knife closures, I would say liner locks and integral locks aren't as good as the axis lock and rolling lock. This is because to close liner and integral locks you must place your thumb in the way of the closing blade. When I first heard that one of the advantages of the axis and rolling locks is that you dont have to place your thumb in danger, I didn't really care. I mean who cuts themself if you're used to closing your knife? Well, I cut myself, twice in fact, and both times fairly recent. Both cuts were because I unlocked the knife, then pushed the blade down too far before continuing the closing motion with my thumb. My thumb didnt' clear the blade and I got cut, pretty badly. I guess I got too confident with my motion. This isnt' a big deal if you watch out, but it's just a plus if you dont have to put your thumb in danger.

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Johnny
[]xxxxxx[]=============>
 
Snickersnee:
Yes, the blade has to pivot to open. By no moving parts I mean that the blade, pivot pin and handle slabs are solid and don't "spring" into a detent or notch, as the liner of a liner lock or the spring powered locking pin of the axis.
The way the "lock" works is that the handle slabs rotate in opposite directions, each handle has a 180 degree rotation stop which contacts the shank of the blade when fully open or fully closed. The two rotation stops are on opposite sides of the shank and hold it solidly between them. It functions similar to the Barry Woods flip over lock except that it is an external, fully exposed system.
I'm not trying to argue, I'm just trying to explain how this lock functions. If I can find out how to get a scan of the print posted that might help.

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P.J.
YES,it is sharp, just keep your fingers out of the way!
www.silverstar.com/turnermfg


 
PJ, I think I know what you're talking about. A lock that's similar to what you describe is found on some 19th century "navajas de secreto". There's an illustration of one in La Navaja Espanola Antigua.

Drew, it ends up there are a whole buttload of locks and variations of locks in navajas. Some were even slip joints.

Anyway, the variation of the clasp lock I'm talking about doesn't allow for much vertical play due to the bladestop.

I don't follow what you're saying about "peen the front of it", if you could explain...

You're absolutley right about the hole deforming under pressure. That's the main problem with most of the repro's made for export/tourists.

In the real deal you've got a truly massive spring and you're talking ungodly force to deform that hole. The springs are on average about 1/8th an inch thick(on the big ones) and nearly the full width of the handle.

The main thing is that bladestop soaks up the force from any edge-to-spine pressure, and you only stress the lock itself to resist closing.

Joe, the failure occurs at the point when your grip starts to slip. Not usualy a problem, unless your elbow deep in greasy grimy gator guts, or somesuch. Don't get me wrong, I think integrals are as good as you can ever make a lock in the linerlock family, I just would rather a lock that was completely incapable of accidental/incidental disengagement.

No lock is indefeatable. As Drew hath said, the main thing is getting a lock that's been well done. A poorly done lock of any type will suck. That's the problem with most of the navajas, and clasp locks in general, on the market today. Balisongs too.
 
Snick,

You're right that the blade-stop will take all of the force from pressure to the edge, which is by far the most common type. My concern was that repeated pressures or shocks to the spine might deform the hole, and I think we agree that simply making the lock suitably robust will keep this from being a problem.

When I talk about peening, I mean that the metal could become slightly compacted on the front edge of the hole, increasing its diameter and thus allowing play. As a malleable material, metals do have some ability to be compressed and this is a major source of deterioration in the actions of many folders. This is why most linerlocks employ a hardened steel stop-pin even if they have a handle made from another metal. If the blade stops against a softer material (as in the Kershaw Liner-Action series, which uses its aluminum spacer), this peens over time and the blade travels further and further back until play develops.

-Drew
 
I think Joe is dead on about the integral lock tightening up when you squeeze, but only if your right-handed with a right-handed knife. I have a Pinnacle, and think it's a great knife, but I won't ever use it because I'm left-handed. When I squeeze it, it can and does disengage. Not a comforting thing!
For this reason, and others, the Axis Lock is my favorite. A little Gun Scrubber and TufGlide, and I have no fears about fouling causing a failure.

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Knowledge without understanding is knowledge wasted.
Understanding without knowledge is a rare gift - but not an impossibility.
For the impossible is always possible through faith. - Bathroom graffiti, gas station, Grey, TN, Dec, 1988

AKTI Member #A000831




[This message has been edited by Codeman (edited 17 August 1999).]
 
Codeman,

Now you have me concerned! I am left handed as well, and have dreaming about a Sebenza somewhere in the future. I have always felt that Lefties are more adaptable than righties. I generally am happy using a right handed tool, and am much more adept at it than my right handed friends are at using left handed tools.

Now you are telling me that the integral lock ala Sebenza/Pinnacle contains a hidden trap for me. Damn! I will admit that I had at least considered the possibility, but I had thought, and rather hoped that the index finger tip pressure, wrapped around the knife and coming from the other side would counter act the problem.

I guess I had better find a shop with a Pinnacle I can play with for a little while before I go for a Sebenza I was hoping, when the time comes to buy a Sebenza that I could get regular knife "off the shelf". The lefts, I assume are custom order. I am not sure I am willing to go that route.

I have got to think about this. . .


MNH
 
Drew;

Ah, now I see what you're talking about. Yeah, that sounds like it could be a thing, except that not only is the backspring rather beefy all around, but it's also spring tempered, making it harder and more resistant to deformation. At the same time, I haven't noticed this particular failure even in the poorly made repro's. The main problem is they have these sheet metal backsprings that buckle under pressure.

I'm glad you mentioned that though, because I was considering leaving the tang a bit soft, but the tang protrusion may deform and mess with the lock, so I'll leave it with a reasonable degree of hardness.
 
I have had experiences with liner locks failing, so I have been very interested in finding the perfect lock.

The trouble is that any mechanical device can fail. I recently had Pat Crawford make a blade modification for my new liner lock KFF. I had him leave a total unsharpened edge length of 5/8" on the blade at the pivot end. My idea is that in the event of a lock failure the unsharpened edge will strike your index finger preventing a cut. This works well for a knife like the KFF which has a secure finger groove because you know the position of the index finger.

Just a different approach to the problem of folder lock failures.

Axel

[This message has been edited by Axel Yup (edited 21 August 1999).]
 
I think that with most well made folders the worry about lock failure when your actually using the knife is often overstated. In day to day use I have yet to have a liner lock or the integral lock on my Sebenza fail. Doesn't mean they can't I just haven't had it happen. For that matter I once skinned, gutted, decapitated and caped, and butchered a Mountain Sheep in the field with a Spyderco Police model and it never came close to failing either. Again I am sure with the (in)appropriate amont of force and the right test I could make any lock fail. Just not in daily use.
 
Johnny - I believe that you will find, as you continue your search, that the manufacturing of the lock will play more of a role in safety than the type of lock.

To say that "Sports cars are unsafe" because you know someone that crashed one is unfair. To say that a certain design of lock is inherently unsafe is equally unfair.

We make lockbacks that will wear out the person in the spine wack test and withstand more than 400 inch/lbs of force before failure occurs. OTOH, we've tested lockbacks that consistantly fail with a slight tap of the spine. They are both lockbacks, right?

Linerlocks are a "bugger" to consistantly make right. We've tested good ones and we've tested junk.

Most of the time better knives came from the companies with a "name" that they wish to protect and honor.

An Axis lock with the wrong angles at the spine or an inferior spring will be "less safe". The same goes for a Rolling lock. Even the "frame-lock" (What we usually refer to as the Chris Reeve lock) at the wrong angles at the interface will slide like stepping on a piece of fresh bacon.

Careful execution of the correct geometries make for good locks!

New designs are great, and time will show their strengths.

I know Chris, Lester and Bob. I can assure you that these men (and their mates) extend their best effort to "do it right".

Time and attention refine good designs and we all benefit. Just another opinion.
sal
 
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