Let me see if I can clarify some terms for you.
"Flick" is a quick snap of the wrist, similar to the motion you use to throw a Frisbee in the usual back-hand manner. Hold the knife by the handle and push it away from your body in a backhanded arc motion with a flick of the wrist at the end. Note that this can be done without touching the thumb hole or stud, or you can use it in conjunction with the thumb hole/stud. This technique works well with liner-lock knives, provided that a) the pivot screw is not too tight; b) the ball detent is not unusually agressive. It's more difficult to do with a lock back: it takes a more violent whipping action to overcome the pressure of the back spring. The larger (heavier) the blade, the easier it is to flick. I can "flick" a Delica in this manner (it takes a bit of practice, and there is some risk of accidentally letting go of the knife), but an Endura is easier. The Military takes the prize in this event, since you have a relatively massive blade and not much spring pressure (no back spring--just a tiny bit of pressure from the depressed liner lock spring) or friction from the ball detent. It's basic physics: Force = mass x acceleration. A relatively massive blade, once set in motion, will have enough force to overcome the ball detent and/or spring tension. You can "flick" a large AFCK open more easily than a small AFCK, assuming equal pivot and ball-detent friction. Flicking open a smaller knife, such as a Benchmade Leopard, is quite difficult to do, unless you use the thumb stud overcome the ball detent initially.
"Drop" is when you open the knife by grasping the spine of the blade (at or near the thumb hole, if it's a Spyderco) between thumb and index finger and jerk it so that the handle falls downward. Spyderco and Sal Glesser popularized this maneuver in the early 1980's, but the technique was in use for many years before that. You don't need a hole to do the "drop", although it definitely helps. You can "drop" open a Buck 110, or even a much smaller knife, such as a Gerber LST. Just as we need a heavy blade to perform the "flick", you also want a heavy handle to perform the "drop". You can drop open any knife, though, if you jerk it hard enough, provided only that there be enough of the spine protruding above the handle for you to grab ahold of. (It is very difficult, if not impossibe, to "drop" open a traditional slip-joint stockman, incidentally.)
"Shake" is the term I use to denote the first part of a combination "shake and flick" technique. Grasping the handle, shake the knife hard to set the blade in motion (overcome the inertia). As the blade is falling out of the handle, you perform the "flick" action described above.
Longden: I wouldn't use the word "twisting"; it's really more of a "jolt".
Chinook: I can open my Calpyso Jr. BM using the "shake-and-flick". I just did it to verify that. I wonder if I can "flick" it open without the "shake". (I'll have to be careful, as this is a very slippery handle!) ... Heck, that worked like a charm. Wow. I wouldn't have thought I could to that so easily. Try it. You've just got to find the right amount of energy to overcome the spring tension. Not all knives are created equal. Yours might be stiffer than mine is. And you're right about the Vaquero Grande. Forget about the thumb studs on that sucker (which are rather poorly designed anyway). Just wheel that thing around and the blade swings open like the gate to Dracula's castle.
Man, I love knives.
David Rock
------------------
AKTI Member # A000846
"Never carry a knife shorter than your schnoz."
