SOCOM Lock Failure


I agree that too much effort has been put into testing lock strength in this unlikely direction at the expense of testing in the proper cutting direction. I DO feel that "spine whack" and similar testing is an important concern because failure in this direction puts your fingers at risk, but we need more "normal use" testing as well.

I would consider the "spine whack" abusive if I had not seen so many knives endure it without failure or damage. I can literally take chunks out of a desk with the spine of my AFCK, Military, Starmate, or even S&W SWAT, and none of these knives EVER fails, jams, or suffers any noticeable effects (the same ecannot be said for the desk). True, I can only imagine a few extreme situations where such force would come into play when using a knife, but clearly it's not that hard to make a knife that will withstand it. We should expect this from all of our full-sized, "hard use" liner-locks, most especially the astronomically priced Microtechs.

-Drew Gleason
Little Bear Knives
Okay, regarding spine-pressure testing ...

I feel all the tests are sound, but if a particular user tells me "I never do X", then for that particular user, I can't argue that he should be testing X, of course.

In general, I feel that any user will want to do white knuckling, torquing, and spine-steady-pressure tests. Even gent's knives occasionally get twisted and torqued, quite often. Any real using knife can be. The worst case gets all 3. For example, many people have reported failures when they were slicing something rather big or heavy, and the blade wedged a bit, and they started torquing the blade to release it. This involves white knuckling, torquing, and steady spine pressure, and liner locks fail at this appallingly often.

But spine whacking is different than applying steady pressure to the spine. I believe spine-whacking is a perfectly sound way of testing, but if you're convinced it's not, it's your call (but don't too smug -- liner locks fail white knuckling and torquing tests all the time, too). Under what situations might the spine suffer impact in real life? Many of the situations are admitedly out there. Someone wanted to absolutely trust their folder for a last ditch defense weapon might not want it to fail if the spine is hit with a stick, say. A hard user might worry that if the knife wedges somewhere and he yanks it out, the spine could hit something on the way up. Any kind of hard stabbing or other point penetration, if done at a slightly off angle (relevent to both defense and utility use) could simulate a lot of impulse spine pressure.

If you're perfectly happy not worrying about these things, that's fine. But if I'm going to carry a knife for hard use and any contingency, I want it to pass the spine whack test -- why should liner locks, the only locks which routinely fail this test, get a free pass? And if any knife is sold as a "hard use", "overbuilt", or "tactical" folder, I feel it's not only fair but obligatory for the owner or reviewer to evaluate it as such.


[This message has been edited by Joe Talmadge (edited 12 July 1999).]
Further to what Joe has stated, its not only the exact forces that need to be looked at (blows to the spine during a fight) but other things that could cause similar stresses. For example, put the blade in a vice and do a sudden jerk on the handle. Not a direct liftt up, but press down with your palm heel and up with your fingers. This will create a torque on the lock similar to wacking the spine. This kind of thing can happen to a knife that gets lodged in something and you try to yank it out.

For what it's worth my Spyderco Wegner has been ultra-reliable from day one. If I whack the blade the lock only seats farther over. (only on the 1st whack) I have tried all manner of tests and I cannot get the lock to fail. It may not be a "tactical" knife but it is strong, reliable and takes a keen edge. It does everything I ask of it. That's "tactical" enough in my book!

Joe, with all my respect for your expert insight in this matter, I have always been taught to use the right tool for the job. I would choose a fixed blade for most all of the conditions that you describe.

As far as the knife fight scenario, slash and run.

I still do not understand all the "whacking", but it seems to be a good test on the lock. I have never hit the back of the spine on any of my knives and I use some of them in pretty extreme uses.

But again, I defer to your and Cliff's expertise and have used both of your testing results when making my buying decisions.



[This message has been edited by Daniel (edited 13 July 1999).]
Didn`t A.T. Barr start this test?I think that it is a good idea to expolore the envelope.

The twisting and torqueing test is the most critical one, I think, along with just simple, steady closing pressure. Often times though, steady closing pressure won't cause a liner lock to release, but a moderate whack does. To me, that indicates that somewhere on the continuum between no impulse and moderate impulse, the lock will release, and that point could vary widely depending on how clean and well lubed the lock surfaces are. To me, it is very unnerving not knowing where that point is.

Daniel -- well, as I said, no one knows what you require better than you. If you always have a fixed blade handy and only need to use your folders lightly, that's cool.

I will comment on the "right tool for the right job" statement, which I hear often whenever lock failures come up. First and most importantly, I don't believe a folder is necessarily the wrong tool for many of the jobs described, from utility work to backup defense work. Cutting cardboard is a perfectly reasonable use, and the blade can easily wedge. There have been numerous failures leading to stitched fingers due to this. So even lightweight jobs can end up leading to unexpectedly-high strain. Really, a hard-use folder should (and many do) stand up to some pretty heavy use, which is a good reason to expose the pretenders.

Just as importantly, even in those cases where I agree a fixed blade is better, there are many situations where I just can't carry one. Maybe it's not comfortable, maybe (as in my state) it's illegal, etc. So egging the folder makers on to manufacture ever-more-reliable locks is a role I'm happy to play.

One would have to think that there is a reason for a growing demand for a RL, an Axis, or a Speed Tech lock. These are coming up strong, perhaps, because of a better "mousetrap".

Whether a knife is used for utility or defense, accidents can occur during use, and I think it unfair to take up as much space as would be needed to give examples of how these situations could occur. I already said this in KnifeForums, but I think it bears repeating here: Those of you who give no credibility to spine whack tests should by all means continue to do so, I just hope the reattachment surgery goes well. I further assume that to get to the ER you will be driving your Pinto (with a full tank of gas), in reverse, blindfolded.

Tantos came up fast, as did chisel grinds. I'm not saying that new locks are as useless as either of these fads, but we should be careful not to assume that an item's popularity means the old way was flawed. Some (not me) would even make that argument about the rapid rise of linerlocks...

Joe Talmadge:

Can you tell by looking at a liner lock if it is likely to fail? I can't. Can you tell by looking at a liner lock that it needs to be "seated"? I can't. Why do some fail and others don't? Why do some "seat" and then others will continue to fail? What is happening when the liner lock fails? I don't know. The liner lock shows no change before or after it fails. No bent liner, etc.

I believe, and I may be wrong, that anyone who buys a liner lock, for other than to put in a display case, would prefer it not fold after a whack on the spine. It may not be essential, but if anyone had there druthers, they would prefer it not to fail. If you were making a custom, such as those made by A.T Barr, R.J. Martin, Greg Lightfoot, etc., how would you design the knife to hopefully pass the whack on the spine test, or torque test? You got some very stout "overbuilt" folders out there that will fold with a moderate whack on the spine, and you have some "lightweights" that you can hit with a ball peen hammer and won't fold.

Any thoughts from the FAQmaster?

I agree about the chisel grind. I don't care for them though it has it's proponents, and makers continue to sell them. As for the rolling lock and, I forgot -- the integral lock, I can say neither has failed me yet. I carry one or the other daily (along with my BF Native.
) Can't say that about my linerlocks. Even my KFF failed once on a spine whack. Hasn't happened since but that peace of mind dented a bit. Thus, I am still waiting for my Crawford Carnivour. It's just me. I want to have confidence in a my "tactical" and I willing to pay for that.

JP --

You can tell some things by looking at a liner lock, but it's easy to come to wrong conclusions. For example, I hear many people complementing a knife they just got by saying the liner lock is engaging right in the middle of the blade tang, as if they believe a lock that engages in the middle or to the right is much more reliable than one that locks up to the left. Not necessarily true, I've seen 'em fail -- or hold -- from all across the blade back.

As far as how to make a liner lock that's solid, one of the makers whose knives are rock solid knows way more than I do. But here are some of the qualities that I've seen often on liner locks that hold well:

- Good blade tang to liner lockup. Angles are just right. The blade tang is at 7 degrees or maybe even less. This might make unlocking a little sticky, but it's worth it. If you're looking for perfection, there's at least one maker whose lockup is rock solid, but he's done the tang/liner juncture so well it doesn't stick at all!

- Good pivot washers. Big and thin seem to be a big advantages. If the washers are small or thick, they can let the blade tang wave around when the blade is under torque, and that affects the lockup.

- I've seen *very* thin liners hold rock solid, and there's at least one maker who can make a thin liner lockup perfect every time. But for most makers, thicker liners are safer.

- Liner cut below the handle scales, however low they need to be to keep from white knuckle failures. This is another feature that can make unlocking a bit inconvenient.

- Rock solid frame integrity. If the knife handles can twist under torque, that affects the lockup. Besides the customary 2-3 screws and a spacer, multiple guide pins to lend stability to the structure seem to help a lot.

Has anyone brought this to Microtech? What do they say about the problem? Has anyone returned a knife to Microtech for repair? and if so, did they fix it? and did it stay fixed?

I have no idea whether the test is valid or not, but my 4 - 5 year old AFCK has no problem in this regard.

MNH, it has been brought up at KnifeForums in the Microtech forum recently and the Admin simply stated this test was abusive. He does have a point. Since it it causing the Microtechs to fail, they were obviously not designed to take this stress, so it probably could be called abuse. It seems to me Microtech has way too low a standard for knives that intend to be used.

For those out there who want to just use folders for light work and are %100 secure than it will never take any shear stress or direct torque on the lock, its your knife feel free to limit the use of it in any way you want. My question is though, with many knives with rock solid, very secure locks like the Axis, Integral, Rolling etc., why not buy one of these as a user. There are lots of knives that can stand heavier use so why buy one that is directly weaker?

Thanks Cliff,

It seems that with the level of discussion going on here that Microtech would be a little more forthcomming.

I would think that they would either go to some length to a.) convince us that the test is not valad, and back it up with a detailed explination. ro b.) repair the knives in guestion.

Microtech has established quite a name for themselves in a very short time, perhaps primarily for automatics, but as long as they continue to manufacture DAs and manuals. . . sooner or later they are going to have to answer the questions to everyone's satisfaction, or suffer the consiquences.

I have been following the progress of this post since it was submitted as I find the topic and replys quite interesting.I initailly tested my m/a SOCOM not completely sure of test technique my lock held time and again.Being unsure of my testing method I have done some research on this forum and KF which hyperlinked back to BF'S.I think I have a good understanding at this time on actual test procedure mentioned by Joe&A.T. If I can refer to these genteman by first name or initials.I tested a number of my liner-locks in this fashion including m/a SOCOM.The only knife I tested that failed, quite miserably ,is marketed and designed strictly as a fighter this knife is a Gerber Applegate large model,don't really like that knife anyhow.I in now way claim to be a knife expert but I do understand mechanisms. These are my test results.
Don't understand why some manufacturers consider the liner lock whack test as abusive. You are only banging the blade spine. I do mine on a well used cutting board. Never once even marked up the spine.
I would like to know why it is abusive. Intersting point bought up by one of the formites though. My 1416 when given a good thunk, well the lock just moves over to the right a tad bit. Is this what is called seating the lock? thanks and keep'em sharp.