In a slim gentleperson's knife with a working class price, there's nothing wrong with an "old-fashioned" ambidextrous lockback.
There are a bunch of liner locks among my favorite folders, but it's a mechanism that can go from very good to awful if some dimension or angle is "off" by just a mili-smidgenth of an inch. You have to get the ball-bearing detent just right, between thumb-busting and edging open in your pocket. And you have to get that lockup just-so, not too far over, but not slipping off when one of us nit-pickers gives it a spine-whack, clinging to the tang, but not binding. Delicate balancing act.
A frame lock is a species of liner lock, where the "liner" is also the handle, and the locking finger is about as thick as the tang. It can be "bank-vault" strong, and there are few places for gunk and grit to get in and jam things or just fester, and it has an elegant simplicity. Apparently "getting it right" looks simpler thatn it is, so factory frame locks with working-class prices are still in the experimental stage. Both Benchmade and Columbia River have done it better the second time around than they did the first time with their frame-lock models, and we look forward anxiously to the production Paragee, whose first prototype showed some of the subtle difficulties of translating the concept into a factory knife.
I've been using a Spyderco prototype Compression Lock for a while now, and I like it. For your thumb or fingers, it works like an upside-down liner lock, and I've had to learn a motion or two that isn't intuitive to do one-hand openings and closings. As with a liner lock, it can be smooth or sticky. Mine happens to be a bit on the sticky side, but other specimens at the Blade Show were smooth. It's very simple, with the locking piece comes in sideways between the tang and the stop-pin, and seems to be immune to spine-whacking by anybody this side of King Kong. It's a small ramp and not a ball-bearing detent keeping the blade inside the handle in the closed position, but it feels like a good ball-bearing detent, and like a liner lock it wants to be carried in the tip-down position. Using it in other brands of knife would presumably require some agreement with Sal Glesser.
My current favorite folder action to use is the Benchmade Axis Lock.
Smoooooth! The thumb push is very easy - the easiest in my collection for introducing non-knife people to the concept of one-hand opening. The two omega springs pull the blade back into the handle the way a backspring does, so it can ride tip-up or tip-down. The lock-up is extremely strong, again in the King Kong range. It's ambidextrous, and one nice feature is that you can close the knife without putting any of your digits even momentarily or theoretically in harm's way. You would be amazed how fearful non-knife people can be of closing a lock-blade folder, though they routinely get in and out of cars without slamming the door on their fingers. Get the motion right, and the handle just sucks the blade back in -
Snap! And then there's the politically incorrect way you can open it, using the lock release instead of the thumb-stud, and gently rocking your hand backwards. Don't do that in front of authority figures, and use the thumb stud under stress because the flip method requires a little timing in your thumb.
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- JKM
www.chaicutlery.com
AKTI Member # SA00001