I think a distinction between the smoothness and lack of resistance needs to be made.
Some knives, like Axis-locks, my compression lock Para2, and CBBL can totally remove the locking mechanism from placing friction on the blade. The blade swings freely.
Other knives, like liner/frame/RIL locks exert force on the side of the tang. Friction between the ball detent and the blade tang create resistance when opening or closing.
My Sebenza, and all of the dozen or so Sebenza's I've handled, have had resistance to opening or closing from the lock bar exerting this force on the blade tang. However, because CRK uses a ceramic ball, the detent ball wears a mirror polished path onto the blade tang. This, it seems to me, is what gives Sebenza's their "buttery smooth" opening/closing. Just like Axis/Compression/CBBL locks, however, I can also push the lock bar off of the blade, and the blade swings freely.
I have found that when I compare a Sebenza to one of these other types of locks, that "smoothness" is not actually there, they simply have a "lack of resistance". If you examine the path that the Axis-lock travels when opening, you will see a small line of raised metal when you look at the blade tang while the knife is closed. On all of ~50 Axis locks I've examined, this line has been there. This small line of raised metal prevents me from claiming that Axis-locks are "smoother" than a Sebenza. Over time, however, the Axis-lock bar does begin to wear the blade tang, but not to nearly the level of polish that the Sebenza does.
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The blade wants to fly out every time I hit the thumb-stud, but a slow controlled deployment reveals just how smooth it truly is--no grit, minimal resistance. This damn knife continues to amaze me...
