Linerlocks. How should they engage the tang?

[Chang]

Lets say I opened up a liner lock knife,
using a Buck Crosslock Solitaire for this.
I point the tip of the blade away
from me and turn it over so i can see the
insides of the handle and the liner lock.
That means the the liner starts on the left
side and slants to the right. Should the
liner go all the way across to the opposite
side of the blade's tang , meet in the middle, or barely move to the left side?

Chang

 

[Dexter Ewing]

A properly executed locking liner should engage the blade tang at the tang's halfway point (or somewhere close to the middle). Depending on the manufacturer or maker, the exact locations of where the lock bar hits will vary. I've even seen them vary from knife to knife of the same production run. There are also some custom makers whose lock bars hit at the halfway point in every knife they make. Bob Terzuola is one who immediately comes to mind. I have two of his folders, and their lock bars hit at the halfway point. Same goes for all of Terzuola's other folders I have seen.

------------------
Dexter Ewing
Knife Reviews Moderator

"The keystroke is mightier than the sword"

 

[Spencer Stewart]

Chang,
The Buck CrossLockk will always engage on the far side of the blade. This does not cause it to lock up though because the blade thickness is the same as the thickness of its "slot". Does that make sense?

Spencer Stewart

 

[Joe Talmadge]

Like Dex, I like to see the liner engage halfway through the tang. However, a linerlock that locks up solid does not necesarily have to hit there. In fact, it can lock up solid even being to the left or right, though there are some cautions. Too far to the left, and it might auto-disengage too easily on you. Too far to the right and, well, we'll talk about that below.

The linerlock is a self-adjusting mechanism. As the liner wears, it gets a little shorter. As it gets shorter, it moves further to the right. However, lockup should remain tight, due to the angle on the back of the tang. That angle on the tang back is what keeps the liner lock tight when it wears; picking the wrong angle is one of the major factors of liner-lock failure, however (that's a different rant, don't get me started

).

Many liner locks will just engage the blade at the far left at first. There's usually a quick break-in period over the first 50-100 openings, over which the liner quickly moves over to the right a bit. That's why many of us (e.g., Darrel Ralph) like to see a liner that's a bit to the left when the knife is brand new. After the initial break-in period, that liner will move over to the right a bit, enough to engage the blade a bit more but still leave plenty of room to wear.

On a properly-executed liner lock, as the liner wears over time, it will eventually move all the way over to the right. There are two possible problems when that happens. First, having reached the rightmost point, if the liner wears any more it can't simply move, so it will introduce play into the blade lockup. Second, it can bind with the blade, inhibiting function.

Usually, getting to this rightmost point takes a *long* time on a well-made liner lock, though some knives, like the Buck Crosslocks you mentioned, are consistently badly done and *start* over way to the right. If this happens on a custom knife, the maker can simply put in a stop pin that's a TINY bit bigger than the current one. Think about this a bit, and you'll be able to figure out why it helps (hint: it will move the liner off to the left again, you'll be starting afresh!).

Joe
jat@cup.hp.com

[This message has been edited by Joe Talmadge (edited 29 November 1998).]

 

[Joe Talmadge]

Comrade Chang, a quick follow-up on my note. I never directly answered your question, where should the liner engage the tang? The answer is this. It should not engage too far over to the left, where it will auto-disengage to easily. It should not engage too far over to the right, where it can bind or eventually make the lock-up sloppy.

Anywhere else, the entire range from left-of-center to right-of-center is perfectly acceptable, and in fact as your liner lock wears it WILL move over to the right. That entire range is okay, PROVIDED THE LOCKUP STAYS SOLID. You still have to worry about auto-disengagement due to other factors. For example, if the angle on the back of the blade tang is wrong, it could cause the lock to fail due to spine pressure. If the liner sticks out from the handle scales, it could auto-disengage when you hold the knife in a firm grip.

Anyway, the point is, there is a range of acceptable places where the liner can engage the tang, but with a liner-lock, you're not out of the woods yet, there are still numerous other problems that can crop up with this lock format. Check the Liner Lock Test FAQ for more info.

Joe
jat@cup.hp.com