Linerlocks - Which ones you trust or don't trust

The linerlock makes contact with the tang of the blade that is angled to account for wear as it locks towards the direction of the non-locking scale. Downwards impact to the to the spine of the blade can cause the linerlock to slip back towards the bias of the angle of the tang, closing it. However, if a knife is used properly, I don't see a scenario like that happening. That's like testing to see if the edge rolls or chips while whacking it on concrete. It will happen if done on purpose.

Military:
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Speedform II:
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ZT0350:
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Nternal said:
Ok but then why does the 50$ Crkt M16-14sf shake off spine whacks like it's nothing but yet people have had problems with there 200$ liner lock folders? Why are they defeated by this test and it is not?
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Some linerlocks will not have the angled tang that compensates for wear, or will have been worn down enough, creating a flat contact surface. This will allow the linerlock to fully extend to the non-locking scale, effectively locking it to that side. When a knife has lockup like that, it will survive spinewhacks no problem, providing the rest of the knife holds.

Kershaw 2420:
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The caveat is, when the linerlock reaches that point, additional wear to the tang or linerlock contact surface will eventually result in blade play, hence the angled tang to maintain tight lockup as the contact surface wears with use.
 
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I think a light spine whack test is good, not crazy like this guy http://www.youtube.com/watch?v=5xruTUJAwvI

Something I pulled up, an older post than one I was actually looking for, pretty much said the same thing.

10-06-2005, 11:15 AM

Sal Glesser

"Spyderco began spine whacking its production folders in 1981. We were
heavily criticized by manufacturers in a number of countries but we felt
then, and do now, a manufacturer is obligated to extend their best effort to
make their locks as reliabily safe as is possible. We believe Spyderco has been instrumental in helping to improve lock reliability in production knives.

We advocate that every customer do a light spine whack of maybe 5 pounds of pressure before purchasing a knife. A lot of knives are far too sharp to
take a chance on an unreliable lock.

I don't believe any manufacturer would make a knife that would intentionally be unsafe. We have found that slight changes in angle or length or spring strength affects the geometry and consequently the reliability in the the lock.

I would recommend that before you use any locking folder that you test them and then test them periodically. A light tap is not going to hurt the knife, but a pile of lint somewhere in the lock would be a nice thing to know.

If the lock fails and it is not clogged up with debris, or has not been abused, then send it back to the dealer or manufacturer. I am sure they would want to know if there is a problem and would be pleased that no one was accidentally hurt........."

I don't think it's a coincidence that linerlocks tend to be the ones to fail spine-whack tests and the ones most often reported to have disengaged on their owner - just seems too related to me :confused:

Aside from any testing I'm just curious which ones besides the Spyderco Military are actually staying rock solid for people after long-term, frequent use. Also hoping it is obvious that if you are using it just around the house in your pj's as if it was a Case Peanut used to whittle some toothpicks, open some envelopes, and cut in half some sandwiches...it's not really part of the discussion.
 
spine whack just checks to make sure the locking mechanism is actually working correctly and that it does lock open the knife, rather than just hold the blade open half-assed....simulates a little shock if anything. A folder that can't pass just a couple rather soft spine whacks is probably less safe than most slipjoints. Better a strong spring holding it open than a lock that poorly manufactured - why settle for it?
 
gooeytek said:
Some linerlocks will not have the angled tang that compensates for wear, or will have been worn down enough, creating a flat contact surface. This will allow the linerlock to fully extend to the non-locking scale, effectively locking it to that side. When a knife has lockup like that, it will survive spinewhacks no problem, providing the rest of the knife holds.

Kershaw 2420:
2011-11-09_23-52-43_509.jpg


The caveat is, when the linerlock reaches that point, additional wear to the tang or linerlock contact surface will eventually result in blade play, hence the angled tang to maintain tight lockup as the contact surface wears with use.
Click to expand...

My crkt m16's liner lock is not like that.It's still angled.
 
OrdnanceBubbaUSMC said:
I think a light spine whack test is good, not crazy like this guy http://www.youtube.com/watch?v=5xruTUJAwvI

Something I pulled up, an older post than one I was actually looking for, pretty much said the same thing.

10-06-2005, 11:15 AM

Sal Glesser

"Spyderco began spine whacking its production folders in 1981. We were
heavily criticized by manufacturers in a number of countries but we felt
then, and do now, a manufacturer is obligated to extend their best effort to
make their locks as reliabily safe as is possible. We believe Spyderco has been instrumental in helping to improve lock reliability in production knives.

We advocate that every customer do a light spine whack of maybe 5 pounds of pressure before purchasing a knife. A lot of knives are far too sharp to
take a chance on an unreliable lock.

I don't believe any manufacturer would make a knife that would intentionally be unsafe. We have found that slight changes in angle or length or spring strength affects the geometry and consequently the reliability in the the lock.

I would recommend that before you use any locking folder that you test them and then test them periodically. A light tap is not going to hurt the knife, but a pile of lint somewhere in the lock would be a nice thing to know.

If the lock fails and it is not clogged up with debris, or has not been abused, then send it back to the dealer or manufacturer. I am sure they would want to know if there is a problem and would be pleased that no one was accidentally hurt........."

I don't think it's a coincidence that linerlocks tend to be the ones to fail spine-whack tests and the ones most often reported to have disengaged on their owner - just seems too related to me :confused:

Aside from any testing I'm just curious which ones besides the Spyderco Military are actually staying rock solid for people after long-term, frequent use. Also hoping it is obvious that if you are using it just around the house in your pj's as if it was a Case Peanut used to whittle some toothpicks, open some envelopes, and cut in half some sandwiches...it's not really part of the discussion.
Click to expand...
I was spine whacking WAY HARDER than that guy was with the m16 and it didn't budge it.
 
Over lubrication can make a perfectly good working liner lock fail. I can't remember the last one I had fail on me. Keep your knife clean and don't lube it excessively. The mating surface is supposed to be dry for friction.

I've owned 3 Emerson knives in the last year and several other liner locks. None failed a spine whack. Striders when they are new are notorious for developing a slight rattle that is just grease and the titanium breaking again against the blade tang. A little rubbing alcohol on the lockup area with a qtip and it is rock solid again.
 
Nternal, hopefully not on denim-covered concrete like he was :eek:

Some will disengage just from letting your arm free fall from a foot or so above a desk - those are the ones that should be weeded out for sure. I think that is something every one could agree to give a try, but I know some will still think it's abusive or silly or even a show of stupidity.
 
Nternal said:
Ok but then why does the 50$ Crkt M16-14sf shake off spine whacks like it's nothing but yet people have had problems with there 200$ liner lock folders? Why are they defeated by this test and it is not?
Click to expand...

Yep, I'm with you here. Why do some liner locks shrug off spine whacks and some fail?
 
OrdnanceBubbaUSMC said:
It has to make you wonder why it's ok if a literally $1 knife that is in every Walmart around the U.S. can do it easily - skip to 1:00-2:00 http://www.youtube.com/watch?v=RToHLXSc9is

Dorito, you are not the first person I've heard about getting a bad cut from a Blur....it's b.s.
Click to expand...

I guess it's nice that some people know with 100 percent certainty, just exactly how their knives are going to be used. Call me a mall ninja but it's that tiny percentage of uncertainty that I want to be prepared for.
 
Ryanol said:
So what are you guys using the knife for that a spine whack simulates?
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Not supporting spine whacking, but I can think of an incident where I have accidentally spine whacked a folder. I work in roofing and sometimes on tear offs I'll be up close to some heating ducts or flashing cutting off some old roofing caulk. The stuff tends to stick to your blades and sometimes bind your knife down a bit, especially when the stuff is warm. I was doing cutting some off next to an AC unit and my blade got stuck. I started pulling on it and it pulled free with some force for me to swing the blade back into the AC unit. Spine whack right there. Blade didn't fold. However, it was my CTS-20CP Para2. Iunno, just throwing it out there, accidents happen.
 
Ryanol said:
So what are you guys using the knife for that a spine whack simulates?
Click to expand...

Nothing, but it shows strength and reliability. As mentioned folding knives fold and locks keep them open. If you're lock shrugs off spine whacks, you at least know that it will keep it open reasonably well.
 
+1 what yablanowitz said.

Trust not, suffer not.

I treat them all like slipjoints.
 
In squeezing the knife moderately hard, any play in the blade is usually one i'll not use. Others I don't trust are any knife with the huge cut out (Spyderco Military for example) that looks like it could accidentally be disengaged by gripping the knife hard. I don't care how unlikely it is I will not take the chance. Strongest feeling linerlock I have is my g10 Tyrade, very thick and assurung.
 
OrdnanceBubbaUSMC said:
ssblood, how solid is your oldest Emerson and how often used?
Click to expand...

Most have been sold. GF is carrying a traveler prestige that is rock solid. The lock up is early on it and I've tried to make it fail and haven't yet.

I prefer frame locks and I have no problems out of then. I was reading yesterday that supposedly a good liner lock is stronger than a frame lock o well. When I need a hatchet I'll use a hatchet. When I want to cut something I'll use my knife.

No offense to anyone but as far as stuff like roofing, etc I'll use the proper tools. Putty knife for scraping caulk and a hook blade in a utility knife cut shingles and such. I'm not using a 200+ knife much less my Umnumzaan to so something that a 10 dollar knife is much better suited for.
 
I grew up using slipjoints, so lock reliability isn't as big an issue to me as it is to others. But I'm just not a truster of liner locks. I've had too many bad ones over the years. I go out of my way to not purchase liner locking knives.

The one exception is the Spyderco Military. I've had a number of Millies, and they've all been extremely dependable. All the stupid things I've done with folders have been while using one Millitary or another, and I've never paid the price for my foolishness. Sal owns my digits.

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