so you get a new endura : fooling with lockback stability

[Cliff Stamp]

Mainly based on recent comments about instability of lockbacks with lint I used a cup of lint and a bag to check out the probability of contamination leading to failure :

http://i7.photobucket.com/albums/y269/CliffStamp/Spyderco/endura/endura_lint.jpg

It took on average about 8 sessions of shaking for 30 s to get the lock bar to not fully engage. The knife was also covered in lint by this time, and you could feel the bar mashing against the lint when opened. It just too a couple of seconds with a toothpick to pop the lint out.

Ok but how about worse contamination so after cleaning out the wood stove I used the soot to get the knife fairly dirty, but it was trivial to clean with just a rap to knock the the dirt out, even if I hand packed it in :

http://i7.photobucket.com/albums/y269/CliffStamp/Spyderco/endura/endura_dirt_packed.jpg


So going to the extreme I made a paste, packed it in and then covered the entire knife in the mud :

http://i7.photobucket.com/albums/y269/CliffStamp/Spyderco/endura/endura_muddy.jpg

A couple of raps and the knife opens perfectly. The handle is also secure with the muddy grip, the checkering is very secure. Clean up was just a few minutes with soap and water.

-Cliff

 

[sodak]

Another urban legend deflated. Amazing what a little testing can do...

 

[puukkoman]

Once again, Cliff, you've taken this one step further than anyone else would have bothered to.

Thanks.

Peace.



p.s.- I'm going to bookmark this thread for the next time some one says "I hate lockbacks because they're unreliable, and one time an ant crawled into mine causing the lock to fail and severing my index finger at the second knuckle!"

 

[pageophile]

With all the new knives out there, I keep falling back to the lockback. Properly designed, I trust a lockback more than any other locking design.

I was at a local "knife shop" and the fella was telling me how he felt lockbacks were the poorest of the lock designs and how liner locks were so much better.

I asked him to show me with my Chinook I, simple enough right. Well, he couldn't get it to fail with some HARD spline whacks (but damn near broken the counter). Next was an CS X2, no luck.

Well my turn, and a liner lock of his choosing (can't remember the exact knife, some tactical unit big and mean). A sharp spine whack and the lock failed first time. Afterward, I gripped the scales tight around the lock and it failed with a light whack. Needless to say, the fella was a little shocked.

 

[knifetester]

Another urban legend deflated. Amazing what a little testing can do...

I do not think this test deflates anything, and I know that lint in thelock is not an urban legend. Many, many others have made the same observatations.
I have had lockbacks fail to engage because of pocket lint on many occasions. Yes, cleaning it out is trivial, but having a knife fail while in use is not.

For me it was no big deal, I was not doing anything that required a strong lock anyways, nothing I would not have used a SAK for.

 

[Habeas Corpus]

I do not think this test deflates anything, and I know that lint in thelock is not an urban legend. Many, many others have made the same observatations.
I have had lockbacks fail to engage because of pocket lint on many occasions. Yes, cleaning it out is trivial, but having a knife fail while in use is not.

I've been using lockbacks for well over 20 years now, and I also had locks failing to engage properly because of pocket lint a few times, maybe a couple of times every year. Cleaning the lock was trivial, just as Cliff mentioned. So, if someone has this happen all the time may I suggest cleaning out the pockets once in a while ...

By the way, on every occasion I noticed immediately that the lock didn't engage properly, so there was no risk whatsoever. That's one of the beauties of a well-made lockback, it locks with a distinctive snap, and when that's missing it's pretty obvious something is wrong.

This contrasts sharply with my experience with linerlocks. After one visit to the emergency unit because of a linerlock that failed catastrophically linerlocks are out as far as I'm concerned. And that was a knife from a well-known, reputable manufacturer, not some cheap junk knife.

Hans

 

[Sal Glesser]

Maintenance on something potentially dangerous is or should be normal.

Put gas in or you'll run out of gas, check the tires, check the oil, keep headlights clean....

Sharpen the edge, clean locks, oil mechanisms, etc....

Thanx Cliff, Reality is a firm, but honest teacher.

sal

 

[bigdog]

I’ve had a lockback fail, due to lint, more than once.
It felt like it was locked, until I tried to use it. I was reaming out a hole – making it larger, with a cutting, prying and piercing motion, when it failed.
Afterwards, I cleaned it out with a blow gun, and just like Cliff said, it was very easy to do. The only problem was that the blood was running down my hand and getting all over the knife. In fact, it was easy to clean up the knife, too. (This was not a Spyderco, but a well made knife, none the less)
The lesson is that you should clean the lint out before using your lockback.

 

[Cliff Stamp]

I know that lint in thelock is not an urban legend.

I demonstrated it can happen, several times. What the above is meant to illustrate, partly, is the probability and nature of the problem as well as issues with cleaning a knife without having to take it apart, even in fairly extreme circumstances.

I did this as well with a liner lock, Military, and three times in a row I had problems with engagement before six shakes. It doesn't take much lint to induce a resistance to the lock bar on a normal opening and thus the lock had partial engagement.

My Military normally opens to two lock bar widths (so there is a full lock bar with past full engagement), however after just a few bag shakings, this was reduced to just 50% engagement, and now the lock bar can experience shear failure.

I don't think any locking knives will function well if very dirty, so this doesn't show that the liner is problematic in this area, just that it isn't a critical specific weakness inherent just to lockbacks. Note as well that lubricant will make the situation worse as will humidity or food juices.

By the way, on every occasion I noticed immediately that the lock didn't engage properly, so there was no risk whatsoever.

Yes, this is one of the things I don't like about the ball lock, it engages so smoothly you can't actually tell it has engaged.

-Cliff

 

[smcfalls13]

Lockbacks are one of the few locks I will trust with my fingers, and I've never had any question about their dependability. Sure they may fail sometimes, but the frequency of failure(at least for me) is much lower than other locks.

Thanks Cliff, for reaffirming what I would always thought.

 

[STR]

I can't say I've had one fail but I sure have had several of the mechanisms get gunked up over the years. I would say they were well on their way to an accident but I always managed to catch them in time.

Nice way to break in your new knife there Cliff. So much for enjoying that new feeling now. Even still it is a good way to find out just how much it takes to really gum things up. I've had some of the crap turn out to be pretty stubborn to remove. A few times I have had to use a small dental explorer to extract it out of the lock recess.

I've always loved lock backs best. It may be just coincidence but it seems to me that after the advent of the pocket clip the gunk build up was significantly reduced in the locks, at least in my pocket anyways. Looking back I had a harder time of it with the ones that rode deep with the rest of the stuff in my pocket.

STR

 

[Halfneck]

My Godfather, who taught me to shoot, did not think highly of the M-16 Rifle he used during Vietnam. Usually he cited how unreliable it was if it got dirty compared to the M-14 he had trained on. Fast forward several years to 1993 when I went into the Army with the notion that the M-16 was a piece of crap. What I learned was that, with occasional cleaning, the M-16 was very reliable and very accurate.

Applying this to my Folding Knives, I never let lint or other debris collect in them. As such I have never had a lock failure.

 

[Cliff Stamp]

My Godfather, who taught me to shoot, did not think highly of the M-16 Rifle he used during Vietnam. Usually he cited how unreliable it was if it got dirty compared to the M-14 he had trained on. Fast forward several years to 1993 when I went into the Army with the notion that the M-16 was a piece of crap. What I learned was that, with occasional cleaning, the M-16 was very reliable and very accurate

There is a lot of room for debate there, which is better a mechanism, one which in ideal conditions isn't as high performance but is much more tolerant to contamination and will continue to function longer or one which in ideal conditions works better but more quickly loses performance without maintaince. This is one of the core issues for carbon vs stainless steels.

I’ve had a lockback fail, due to lint, more than once.
It felt like it was locked, until I tried to use it. I was reaming out a hole – making it larger, with a cutting, prying and piercing motion, when it failed.

The great thing about the internet is the massive amount of information, I can't recall any lint based failures, I never even considered it until I read about it a few years back. I kept an eye on it since then and never noticed anything, but with any low probability effects people can have very different perspectives. We are all generally more concerned about what we have directly experienced.

Nice way to break in your new knife there Cliff. So much for enjoying that new feeling now.

I am with Les Robertson on this, take your new Brend and wipe it across the sand and now you don't need to be concerned about any scratches on it.

Looking back I had a harder time of it with the ones that rode deep with the rest of the stuff in my pocket.

It would be interesting to note how many problems are tip up vs tip down, and what are the typical pant materials. I would also be curious how many of the knives were lubricated (attracts lint) and how many are rinsed and cleaned on a regular basis.

I would also be interesting to do a long term really high sample run on a few locks to see if there is a significant difference in which ones get unstable faster and the effect of various lubricants. Too bad I don't know anyone who owns a laundromat.

-Cliff

 

[Carl64]

The problem with this test is it tests lint obstruction caused by buildup of loose particles. Real lint failures, which I have experienced and I imagine many others as well, happen when a pre-formed lint ball makes its way into the knife. The lint ball is constantly forming, knife present or not, and can get stuck in the knife when it reaches the right size.

When this happens, it's clearly audible. You can feal it too. A sharp clack vs. a quiet and blunt stop. I don't worry about it.

I have only had it happen with knives I put loose in my pocket, so in addition to keeping pockets clean and opening with a little attention, a critical tool could be kept clipped in a back pocket to avoid this problem.

Linerlocks may have a risk too, I just haven't run into it because I usually only carry them clipped to a back pocket where lockbacks don't have a problem either. I hardly ever put a liner lock loose in my pocket because they tend to get bumped open easily. I worry about pulling the blade open when removing my keys, while lockbacks usually have a better blade retention. Lockbacks also pull themselves closed again if bumped open a little, while linerlocks stay open (the ball detent only pulls it in at the last tiny fraction of an inch, while a lockback pulls itself shut 30-60 degrees open).

I can see it happening to a linerlock mainly if the lint gets between the blade and the stop pin preventing the blade from opening all the way. However, linerlocks usually have a space between the stop pin and tang big enough to let the same amount of lint pass under, while the lock bar on a lockback plows lint along the tang. Maybe there is an advantage.

However, getting back to paragraph 3, lint blockage can be avoided on either lock type by keeping pockets clean and/org using the pocket clip instead of letting the knife drift around in a front pocket. If you have time to fish around in your pocket for the knife, you have time to look and make sure it is locked open all the way before using it.

 

[victory]

I clean my knives every few months and use a quality dry lube. Never have a problem

Liner locks just can't hold a candle to lockbacks. I carry an endura now, my prior EDC was a cold steel prolite. For all it's heft and big oversized liner, a sharp rasp on the spine still sent if flying shut. Conversely, i practice knife strikes with my endura trainer on trees.

 

[Krull]

I can't say I've had one fail but I sure have had several of the mechanisms get gunked up over the years. I would say they were well on their way to an accident but I always managed to catch them in time.

Nice way to break in your new knife there Cliff. So much for enjoying that new feeling now. Even still it is a good way to find out just how much it takes to really gum things up. I've had some of the crap turn out to be pretty stubborn to remove. A few times I have had to use a small dental explorer to extract it out of the lock recess.

I've always loved lock backs best. It may be just coincidence but it seems to me that after the advent of the pocket clip the gunk build up was significantly reduced in the locks, at least in my pocket anyways. Looking back I had a harder time of it with the ones that rode deep with the rest of the stuff in my pocket.

STR

You'know I have never really had a pocket-clipped knife get so linted up that it didn't work,the ones I just drop in my pocket? Lord,don't ask! my Ladybug is always getting gunked up riding in my shirt pocket,and my Salt 1 goes in my BDU shirt pocket when in the woods (so I won't lose it) and it needs a bit of attenion afterwards.

 

[Cliff Stamp]

The problem with this test is it tests lint obstruction caused by buildup of loose particles. Real lint failures, which I have experienced and I imagine many others as well, happen when a pre-formed lint ball makes its way into the knife.

The problem with simulating this is the very low probability which is why I simulated a very high lint, and very loose pocket with the knife not being used in a clip and slammed around heavily.

The best way to examine this numerically would be to just do large sample testing, the real problem there is getting real data, since the indicent rate is so low, just a few people screwing around could drastically effect the results.

This is one of the reasons why hype can spread so fast on the forums.

I have only had it happen with knives I put loose in my pocket, so in addition to keeping pockets clean and opening with a little attention, a critical tool could be kept clipped in a back pocket to avoid this problem.

I never even considered this, people use clipits loose?

However, linerlocks usually have a space between the stop pin and tang big enough to let the same amount of lint pass under, while the lock bar on a lockback plows lint along the tang. Maybe there is an advantage.

It looks that way to me too, just poke some lint in the lock bar and close it and do it with the liner, there is a self-cleaning action to the liner, and plus the lint can fall out, it is more trapped with lock backs. One other thing in regards to cleaning, the Endura's scales are very tight with the blade, on some FRN's there is some gap, this might make the mud harder to clean. I'll likely have a look at this later.

-Cliff

 

[Carl64]

I never even considered this, people use clipits loose?

Sometimes I take the clip off of a Delica and carry it as the "extra" knife loose in the front pocket. When I have something bigger or fancier clipped to my back pocket.

Of course I do it more often with the Dragonfly and small non-spyderco lockbacks. Bucklites, medium Voyagers, Gerber LST, etc. But sometimes with the Delica.

 

[knifetester]

I rarely use the clip on any knife and often just remove them. I have seen many cars with scratched paint, as well as furniture, etc from clips. Moreover, an exposed clip tells the world you are carrying a knife, not always a good thing.

I find removing the clip to give me a more ergonomic grip on the knife as well. This is especially true with knives like the Benchmade 630/635.

When I do use a clip it must be tip up carry.

 

[fulloflead]

You should have put that blob of lint in your pocket, along with the knife, and then wore those same pants for a month straight, while using that knife for your EDC and seen when it gave you trouble. That would have been better.

.