I beat the hell out of my Specwar today

[cds1]

Well, I decided that if I am going to rely on this knife to serve me under extreme duress, I had better make sure it is up to job.

I gave it a good number of full force and almost-full-force spine whacks against my hand, then my knee, then the arm of my computer chair (which is cushioned). (I held the handle in such a way that my fingers were out of the path of the blade. To be fair, I'm sure this reduced the amount of force that I could apply.) One time I hit the knife against the chair so hard that it flew out of my hands and landed on the floor.

The liner did move a bit - first it engaged a bit further to the right, and then on a subsequent hit it moved back to its original position - but I was not able to get the lock to disengage.

 

[biogon]

I usually do a couple of different liner tests on my linerlocks.

- Disassemble the knife and make sure the liner is bent enough so that it would naturally travel to slightly past the tang.
- Push really hard, edge-first, and see where the liner travels to.
- Push on the spine
- Light, whippy snaps to the spine
- Heavy, 3/4 power force thuds to the spine
- Push the blade into something dense, and wiggle it left/right and around the axis of the handle while pushing against the spine

These are all simulating things that could happen when in regular use. If it passes, I use it.

The vast majority of my EKIs pass -- occasionally, the lock will slip with the heavy, continous pressure one. One disengaged with the light whippy hit -- it went to the shop and the locking liner replaced and fixed up in a jiffy.

-j

 

[cds1]

I didn't try the first or last test that you mentioned. I'll give it a shot. I suppose I could stick it into a phone book and try torquing and twisting in various directions and see what happens.

Just curious - how often do you test the same knife? I wonder how many of these beatings a knife can take before it starts to loosen up in a way that could cause the problems being tested for.

Regards,
cds1

 

[biogon]

The first one is just to make sure that in the worst-case scenario where the liner is too short, that it'll actuall push up against the opposing-side liner rather than "hang loose". It's my opinion that once the initial stickiness on the lock is broken and it starts to slip, it's a lot easier for the lockbar to be forced off the face.

On EKIs, Spydies, BM's, and some other production knives, the radiused lockface, if done correctly (especially on the Spydies with the "lip"), seems to really help prevent slippage at the final stage (right before it falls off the tang) because the force IS completely normal (perpendicular) to the lock area. This is in contrast to the straight-cut tangs or the radiused ones where the geometry is cut too high; here, the lock almost seems to be pushed right off the tang with the slightest bit of pressure.

I usually do the last test with a couple of layers of heavy cardboard. It's enough to hold the blade in place without sticking it in a vise, and it's easier on the edge.

I do the actual hitting ones probably every 4 months; the pushing one maybe every couple of weeks, depending on if I've been using or playing with it.

As Joe Talmadge has often mentioned, the failure mode of a linerlock can kick in extremely quickly -- one day it works fine, the next day it slips.

For the most part, I haven't found that those kinds of tests will cause premature failure. The first few times you do it, it seems to actually "break in" the lock better; kind of like molding the lockbar mate face to the tang, I guess?

I don't really wail on the spine, just trying to get the same amount of pressure as if I was cutting something in a confined space, the blade gets bound up, and in yanking it out, the spine hits something hard. Hasn't happened to me yet, fortunately.

Lock failure while wiggling the blade up and out of dense material, now that HAS happened to me...

Hope this helps.

-j