Frame-Locks (ala Sebenza)

[UnknownVT]

Frame-Locks seem to be the favored lock for both reliability and strength.

I have just posted a review/discussion on Frame-Locks in the Knife Reviews & Testing section/forum, with photos - here's the link:

Frame-Locks (ala Sebenza)

 

[FullerH]

I asked a question about the difference in utitity between the frame lock and the liner lock over in that thread that I suspect others may be wondering about. I will be the one to look stupid, so you can go look to see if you wish.

 

[UnknownVT]

Originally posted by FullerH
I asked a question about the difference in utitity between the frame lock and the liner lock over in that thread that I suspect others may be wondering about.

...at a sort of an answer -
I'm posting my response here, in hopes that more people may see this and be able to offer some input.

Your question over at the other Frame-Lock Thread was:

Originally posted by FullerH
I cannot see any real difference between the frame lock and the liner lock when it comes to the white-knuckled grip and torque problem that seems to distress a number of people about liner locks.

I'm no authority or expert, so bear this in mind.

If you hold a liner-lock - there is the possiblity that either the thumb could accidentally squeeze and disengage the liner-lock - especially if there is a large cut-out in the handle to accomodate ease of unlocking. Or there is also the possibility in a white-knuckle situation where the index finger could drag/pull against the liner and disengage it. So far, nothing new......

So why would a frame-lock be different?
My main take on this is exactly the lack of a separate handle scale on the lock-side - the handle-slab itself forms the lock. Because the handle lock-bar is exposed when one squeezes the knife handle - it is far more likely that the frame-lock is actually engaged more.

If you look at the photo of the Chris Reeve Sebenzas' locks

one can see it would be really hard to accidentally disengage one with a even a white-knuckled hold.

There are several reasons for this -
(1) Chris Reeve spec's his lock up to have 75% engagement
(2) there is a very shallow cut -out on the opposite handle scale - so that one's thumb or index finger is very unlikely to disengage the lock in the manner described for the line-lock.

However if we look at the Kershaws:

The Vapor and the tiny Chive are again very unlikely to be accidentally disengaged for the same/similar reasons as the Sebenzas -

The only doubts I had are for the LEEK where the enegagement is only a little over 1/3 the blade heel width. In my usage I have found that the exposed handle lock-bar is far more likely to be engage more than it is to be disengaged - again the Leek also has a very shallow cut-out on the opposite handle scale which makes the possibility of the thumb or index finger disengaging the lock pretty unlikely.

Other input on this would be greatly appreciated.

 

[ARtsig1]

I had posted over in the other thread and pretty much said what you've said here. In a "white-knuckle" grip your hand will cause the lock to further engage rather than to cause it to disengage. Even the Leek would benefit in this scenario. The custom J.W. Smith xl RF-1 that I have has about 40% engagement of the lock bar to blade tang yet in a tight grip I don't see ANY way it would do anything but get tighter!

 

[UnknownVT]

Originally posted by artsig1
I had posted over in the other thread and pretty much said what you've said here.

... many thanks for your input both over on the other thread and here.

I think generally on a liner-lock the handle scale on the liner-lock side prevents the user from tightening/engaging the lock more, and the way liner-locks are designed exposes the lock for disengagement only.

Whereas the exposed frame-lock (without separate handle scale blocking the hand) actually will have a tendency for the user to squeeze the lock tighter.

However in a twisting cut there is still the possibilty of either thumb or index finger rotating and possibly disengaging the lock - this is where either the good coverage like 75% on the Sebenzas, or over 50% in the other examples will make these unlikely to become disengaged - or the stiffness of the lock itself (although this may have a downside - in that it may be harder to operate when one actually want to close the knife - as exemplified by the earlier frame-locks that suffered from lock "stick-tion").

Again good observation about the Leek probably benefiting from hand squeeze tightening the lock.

But due to the sheer fact that frame-lock's coverage is less enegaged (just perceptibly over 1/3) the possiblity of the twisting hand rotating disenagement is theoretically higher than on a Sebenza or ones that have at least 50% engagement.

I think in this case it's just a confidence factor - as I have experienced and posted on the LEEK review the Leek frame-lock despite my misgivings has held up well and even when keeping my contact deliberately away from the frame-lock (yes, I can do that ) on twisting torquing cuts through large sweet potatoes (try it, it's pretty demanding for a short/small blade) the lock naturally just perceptibly engaged more - that increases my confidence in this lock -
but doesn't prevent my biassed opinion on prefering to see at least 50% coverage