Failed the Whack Test?

S

silversport

Joined
Jul 22, 2003
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Does this mean my Avalanche is a piece of #@$%&*:mad: ...just tried the whack test although it passed the medium whack it failed a "FIRM" whack and the liner moved allowing the blade to start to close...I have noticed that the liner lock only engages the edge of the blade. On my Emerson Mini-CQC7 it engages at the middle...Will the Kershaw Avalanche (it is quite new) liner move towards the middle more as it ages??? Will this still be strong if it does??? Love the knife except for that...
Thanks,
Bill
 
This is an old topic that is hotly disputed. Some people think that the spine whack test signifies nothing because that is not a natural use of a folder and does not represent the kind of shock or stress the knife is likely to experience in actual use. Others think it is a valid test because a knife may indeed undergo a shock similar to the spinewhack and a bit of overengineering inspires confidence, especially when your fingers are at stake.

After years of deliberation, and putting this as fairly as possible, having due regard to the differing opinions and perspectives on both sides of the debate: yes, your Avalanche is indeed a POS. :)

The liner will move more inwards as it wears. Whether it is properly aligned now is hard to tell from your description. Hopefully someone familiar with your particular pos will chime in.

Noone should be permitted to own any liner lock unless it costs more than $400 US. and was made or designed by someone with a colourful nickname or of curmudgeonly or simply odd disposition. I think we all agree on that, no?

Seriously, a new liner lock failing to hold under a firm spine whack doesn't mean your knife is a pos. But you should check to see if it needs adjusting, and be cautious about using any linerlock for backslashes etc.

My personal view is that a folder should be able to withstand a sharp shock to the spine, or else I treat them like a nonlocker [remember those?], and they should all be treated that way unless you are sure they will hold up.
 
My Avalanche did the same. I took it apart and bent the liner in more and now it passes with flying colors.
 
i personally don't see much of a problem with liner locks. Any high quality production folder SHOULD have a secure liner lock. I believe that your liner lock will get better once you break it in.
 
I believe that your problem has little to do with where the lock engages the blade, and more to do with the angles of the lock face or tang face being incorrect. On a well made liner lock, the face of the lock needs to be at a slight angle that slopes UP to the right, and the blade face needs the opposite, a downward to the right slope, if one or the other is off, then closing pressure on the blade can cause the tang to push the liner to the left and out of engagement, i think you need to send it back. I have a NIB Boa with this exact issue.
 
If you have had a liner lock close on your finger like I have then you probably will not find it acceptable. I would send it in for repairs. Your fingers are worth it.
 
Well, you won't be shocked to hear that I think the spine whack is valid, and I find a knife that doesn't pass to be unacceptable. I use a light whippy wrist snap rather than a firm hammer-like whack (uh, we're still talking about knives here, right?).

One note up front. Liner locks (and to lesser extent, frame locks) usually have a short break-in period once you take them out of the box. That is, they have a period where the lock wears relatively quickly; once that's done, it only wears very slowly after that. I don't advocate taking a liner lock out of the box and spine whacking it right off -- the lock is definitely at its worst at this point. Instead, open the knife 30-50 times, medium-hard (NOT hard enough to damage anything, but enough to shake out any break-in wear). Then if it fails the spine whack test, I worry. I do not do the test until the lock is broken in.

I am with megalobyte in that I feel the lock geometry is the likely culprit for spine whack failures. I'll also tell you that where the liner engages on the blade tang (whether left, middle, or right) is not necessarily a great indicator of how reliable the lock will be. If the geometry is wrong, it's wrong, and the lock will fail. I've seen plenty of knives that lock up way to the left that I can't fail no matter what, and plenty that are over to the right that fail easily. In fact, it is a common occurrence that a knife that passes the spine whack test for months, suddenly starts failing as the lock wears and moves to the right. This refutes the theory that the mere position on the blade is what determines reliability. Why? Because as the liner wears and moves right, the lock geometry changes. The geometry has to be correct across the entire movement of the lock; it's geometry and not position that's the major factor.
 
Joe, then that means spine wacking at the right time and passing means you're not out of the water. As you use your knife, folks will need to test it onced in a while as time passes. Visual inspection will probably not reveal any hidden irregularities in the geometry as it advances over to the right.
 
And just so you know...
The costs of the knife has nothing to do with the reliablity of the lock. I have a Kershaw Scallion and a Gerber Harsey Air Ranger, both rather cheap knives I bought at Walmart, and they both pass the spine-whack time and time again.
 
Originally posted by allenC
And just so you know...
The costs of the knife has nothing to do with the reliablity of the lock. I have a Kershaw Scallion and a Gerber Harsey Air Ranger, both rather cheap knives I bought at Walmart, and they both pass the spine-whack time and time again.
Click to expand...

Not only that, but I've seen very high-$ knives from very big name makers fail. And thickness of the liner isn't a guarantee either (one of the best liner locks makers I've seen has paper thin liners that flex ominously under stress and that lockup far to the left -- I could not make his knives fail doing tests that are far worse than I think any knife should have to take). Just because <X> big name maker produced it, does not mean you shouldn't test the lock. Frankly, I test all my locks, period. But liner locks have at minimum an order of magnitude higher failure rate.

Joe
 
Of course if you are using the folder in a way it was intended to be used. You don't even need a lock.

My Cub Scout folder never closed on my fingers. Neither has any other folder I have ever used.
 
I use my knives for alot of things besides slicing.

I'll use my knife as an icepick to bust up clumped ice-cubes, but I will not try to bust up rock or concrete.

I'll pry open the battery compartment on the TV remote or a small pebble from my shoe tread without hesitation, but I will not try to pry a 16 penny nail from a 2X4.

When using a knife or a multi-tool or a dedicated tool, you have to know it's limits or you're gonna break it.
 
Les you took my thunder I was going to say the same thing for my boy scout knives, they never closed up on me but that was due to good training by the adult and senior scouts teaching us the correct way to use a knife and what NOT TO DO WITH ONE like trust a lock to protect us from dumb actions we might undertake with our sharp tools. I must be missing something because I see no need to use the back of a folders blade to do anything. A fixed blade is a horse of a different color I treat all folders as if they are slipjoints and have not had any surprises. :D :D
 
Thanks guys...I feel LOTS better now...I remember the Scout days and the Tote-N-Ship...never did on me either...I'll try and remember to use my knife as a knife...The proper tool for the job.
Bill
 
...On the other hand...just tried the test on 3 of my knives...

1.) Kershaw Avalanche---passed the 1st whack and failed after that

2.) Spyderco Delica FRN---Back Lock---passed (but then these are not supposed to fail this test)

3.) Emerson Mini-CQC7B---passed again and again and again...WOULD NOT FAIL!

I am a little nervouse now about the Avalanche...an e-mail to Kershaw was put out and I can let you all know when I hear from them.:eek: :rolleyes: :confused: :( :mad:
 
never had any of my liner/compression lock fail the whack... 2 crickets, 3 salsas and a military.

tufram cricket I've given pretty good whacks too, the lock hasn't moved from where I got it, since march 01. Millie has gotten pretty good work, and other than the break-in room, to get the liner so it hits fully inside the tang, hasn't moved, aug 02...
spyderco makes liners that work well... the millie does 150lbs/inch I beleieve...

edit: but then again, I also rotate 3 slipjoints...
 
Well you got me curious too, and since I have more Kershaws than any other brand other than Case which is my pride and joy and tested all the linerlock models I Have. Results are : Blackout model 1550st passed every time ,it was used for 90 days and put away. Mini-task model 1500 never failed 1 year of heavy use,Random task model 1510. passed 1st time then tried to close, use- zilch,nada,none,just played with in house,(gotta love that speed safe mechanism)so Joes theory holds in my case! Thay do need to break in and it seems the more use they get the better the liner lock functions. It will take a LOT of wear before the liner makes it across the tang and loses its wedging capability IMHO.The rest,frame locks or lockbacks,I doubt the lockbacks would ever fail.The model 1050 Folding Field sounds and feels like a bank vault door closing. Dang near feels like a fixed blade it locks ups so solidly/ Blue Mountain model 3130 solid too no failures there either.:D :D
 
e-mailed Kershaw...they say send it in and it will be fixed...they could have told me, as I suspected they would, that the spine whack test had no merit...instead they said the blade and liner lock can fail if they don't mate properly...send it in and we will fix it to your satisfaction...:eek: :cool: :D :)
 
I'm glad Kershaw is going to fix it for you.
It's good to see a company stand by its products.

As much as I dislike liner-locks, I do love the Ken Onion designs!
I have a Scallion and the Speed-Safe is just so cool that I'm considering a Boa.

Allen.
 
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