Liner lock position

Joined
Jan 28, 2003
Messages
7
Is there anything wrong with a linerlock that engages at the very far end of the blade (i.e. a lock that engages to the very right when facing the blade)? I would think that this would be advantageous because it means there's more distance for the lock to move before being disengaged.

My linerlock (Gerber AR 3.0) has eventually started to engage toward the far end of the blade, and if I want I can move the liner even further. I haven't noticed any problems with my knife, but was curious as to what may be a potential problem. Thanks for any responses!
 
By design, the liner is meant to march steadily towards the right as it wears -- in theory, that should allow the lock to wear without ever developing blade play. The blade tang is cut at an angle, so as the liner wears and gets shorter, it moves right where the tang angle causes it to stay snug.

When the liner moves all the way to the right, then you have a problem, or rather, you're just a hair's breadth away from a problem. If the liner wears just a little more, it can't move any further to the right to self-adjust, so blade play is what necessarily results. Or, on badly-designed knives, the liner gets caught and binds up between the blade and far liner. In any case, a liner that locks up at the far right is at the end of its useful life, generally speaking. On some knives, a slightly larger stop pin can be installed, and that will send the liner back to the left again to start the process all over. If you think about it, you'll see why.

Generally-speaking, lockup at the far right is no guarantee of a more reliable lock-up. Reliable lockup is all about liner/tang geomtry. In fact, it's been noticed by many people that a liner lock that was very reliable will suddenly develop reliability problems ... in other words, as the liner has worn and the liner has moved to the right, the lock got less reliable, not more! Or, in other words, the geometry changes as the liner wears, and that can introduce problems.

Joe
 
actually, i think what joe said was when linerlocks wear, they become more and more unreliable
which makes sense, actually
 
I don't have any really old liner locks, so I can't say anything about wear to the lock/tang junction. I have a 4-5 year old Benchmade spike which has been used extensively. It has little or no wear on the liner/tang faces. Based upon this, I'd say I've got at least 10 more years before metal wear will affect the lock-up. The knife does however have wear on the stop pin from hard openings. I would hope knife companies would take the differences in hardness of the tang and liner lock into consideration during steel selection and hardening.

My experience with Spydercos and Benchmades is the lock position changes due to the handle getting a little bit loose. Often times tighteneing up all the screws or a slight pivot tightening with lock tight can make a dramatic change in liner placement. The change in liner placement is not at the expense of smooth opening (i.e. it wasn't cranked down, just a slight tightening). This has been true for me with a Spyderco starmate and the Spike.

I have read that stop pins can wear with hard openings causing the liner to move. I believe the slight permanent movement I've seen in my Spike's liner is from stop pin wear. The pin has flattened where the blade contacts it. Some people have fixed this by loosening or disassmebling the knife and turning the stop pin so the knife hits a fresh surface. Glesser of Spyderco has stated that stop pin materials, heat treat, construction, etc. is often the secret of a good liner lock. By this account, a cheaper liner lock may have more problems with stop pin wear. The same is probably true about liner wear at the tang junction.
 
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