Liner locks fail???

Joe Dirt many times liner locks are simply too accessible. What I mean by that is this. Look at these two pics.

Both are a knife design by my partner and friend, Dirk Potgieter known as Oupa at my homepage and on the forums.

The one in the link is by Bill Vining
The other is the same design that I made for myself using high carbon steel. Notice the difference in the access ramp area to release the lock? I didn't like how Bill's was so hard to access and when the lock stuck, which it still does and really hard it was actually painful to depress and took enough pressure to make it move that if you did it a lot it would eventually take off skin from your thumb. However the fear of accidentally depressing the lock with this design is pretty much eliminated.

So, when I made my knife I thought to myself, well I'll just improve that access area and as a result I made my lock access a bigger half moon shape. And while it is much easier to depress the lock now it is also somewhat of a flop in certain grips because you can feel the lock move just a little bit from the meat of your first knuckle rubbing it when you grip it.

It is a real dilema with a liner lock to get one that is just right from all angles. To me liner and frame locks are basically the same with one big exception. At least with the frame lock you can squeeze and actually make the lock move in farther the "right way" instead of "the wrong way" that can potentially release the lock.

I hope that makes sense because my point is that it may be possible to remake just the liner side of your knife and reduce the access to prevent this accidental partial release.

STR

http://www.bladeforums.com/forums/attachment.php?attachmentid=45593&d=1124221000
 
Joe and STR,

Thank you for the responses. I understand very well what both of you mean. I think I'm just going to retire this knife from carry and just chauk it up to a good learning experience. I have quite a few Axis locks from Benchmade and I now see why I like them so much.
 
I've had a few liner locks and never had a problem. I'm still having a bit of a problem figuring out how someone cuts themself if the knife is being used for cutting. Are we talking about the lock failing during penetration of something?I don't understand the spine whack test either. The only time I could see myself using a knife in this manner might be to use the tip as a glass breaker. Iv'e read the whole thread and someone mentioned failure during some branch cutting, but it's a bit unclear to me. I might be way too thick, but I'm just not seeing it happen through regular use:confused: . And when I say regular use, I mean cutting with blade down.
 
In dynamic cutting (you are moving or the media is in motion) forces can be exerted on the spine or drag on the flats to act against the lock, this can also happen if you try to withdraw the knife when it gets stuck, or on a hard thrust, or if the knife simply accidently hits something, or something accidently hits it.

-Cliff
 
Cliff Stamp said:
Return it, it is defective.

-Cliff
Click to expand...

Would I be thinking correctly that any 910 I did this to would respond the same? They are all the same knife. So is the 910 defective? How would I even prove such a thing to Benchmade? You would think that being as that knife is a black class knife and put out more or less for police or military that it would be for "hard use". I would never use it that hard but I'd like to think if I wanted/needed to that I could.

That's why I'm pretty much prepared to take a loss on this knife and just not buy another liner lock. Thankfully it's the only liner lock I have.
 
Joe Dirt said:
Would I be thinking correctly that any 910 I did this to would respond the same?
Click to expand...

On big factor is the general construction, specificallyhow it sits in your hand and the liner lock recess, but the actual fit of the liner to the tang can be an influence as well which can make it more of a problem on some than others. I returned a Military which had this problem and it was addressed by Spyderco and made significantly more resistant to white knuckling.

How would I even prove such a thing to Benchmade?
Click to expand...

Just say what happened, it is a known issue with liner locks. They have an online forum, you can bring it up there as well.

-Cliff
 
May I jump in here, after just finding this thread, and ask about a CRKT Crawford Kasper model 6783, which is a liner locker with the LAWKS lock thing.

Would this knife fall in the category of knives you all are talking about here? Any known failures with it?

And is the locker supposed to be automatic. This one does not lock automatically.

I got this one as a gift. Is a big heavy thing..
 
LAWKS is manually engaged.

Please test your own knife, as each knife is unique in its manufacturing.
 
If you rough up the surface of the tang where it engages the liner lock, it will hold fast under stress and not fail. Strictly speaking, there must be the tiniest of gaps between the tang and the lock so that the lock can fully extend when the blade is deployed. The knives that I own already have this gap (less than the thickness of paper) but I suppose it's possible that not all knives do. With the tang roughed, I've never had a liner lock fail. However, I have had several lockback knives fail back in the 80's and avoid these now.
 
Krull said:
It has Zytel scales combined with real thin stainless liners..the thing is "squishy" I know no other way to put it,you can compress the damn handel by squeezing it! :eek: flex or twist it and the lock goes bye-bye (not that I ever tried) plus the lock on mine doesn't really go right..about maybe a quarter of it hangs off to one side...stick with CRKT's metal or G-10 scaled knives.
Click to expand...

My only liner lock is exactly CRKT Point Guard Large and it never fails me. It passed all the test without LAWKS.

Edited to add: if you search for my review of that CRKT PG, it passed Barr and Talmadge test. However, last night I did another test, whacking it hard against a plastic tub and it even seat the lock further (the lock move further towards locking, not opening). Also the fact that in the event if the lock fails, the folded blade will not bite my hand because the tang will hit first (and not the edge). This combination is enough for me on THIS particular one I have.
 
I sat back and felt like re-reading this thread tonight. After doing so I'm still wanting to buy another liner lock. I really am looking at the SERE 2000 from Al Mar but I have no way to try them in person. I'm starting to think that liner locks can be OK and it matters how you hold them and how you treat them. I just find it hard to not let myself buy liner lock knives when I like so many of them. I was trying to stick to Benchmade and the Axis lock but there are a great many knives out there with liner locks that I have never tried.

I'm thinking that I will end up grabbing a SERE 2000 and if I don't like it I could trade it.

Not trying to "hijack" this thread, just expressing a new view.
 
I don't think ALL liner locks are okay, even among the same model of knife--but check the lockup. Since that seems to be an impossibility (for you and me both) call up NGK and have Mike take a good look at it. If you don't like it, they'll even take it back, or at least, they've been willing to do so far me.

However, I hear Al Mar's fit and finish is top notch, so probably no big concern.

This sounds bad, but I'm really only concerned when I order Spydercos...which I suppose is a testament to how good the designs are since I still mostly order Spydercos.
 
i have had to return a CRKT kasper with a bad liner myself FWIW, CRKT liners are "iffy" at best imho.

the lawks is an ok idea but the liner still needs to engage right imho.
 
My friend recently bought a Kershaw Tanto Blur from Wally World and had it for about 3 weeks and used it as his beater knife (Never really abused it, just used it when he didnt want to scuff and damage his nicer knives) and stabbed it into the wood near his bed without much force when the lock disengaged. He didnt stab it hard enough for him to cut himself so he was lucky. I took the knife and did 1 spine wak on my boot and it closed under the slightest amount of pressure...I would say i put maybe 5-10 pounds of pressure at most and it just closed all the way. I dont know if he got a defective one or what but niether me nor him will be purchading another Liner Lock anytime soon.
 
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