runT1ME said:
Well, what about spine wacks? Have we found out if Lockback is prone to becoming disengaged if struck hard enough?
I don't have the model in question, but no. Lockbacks can easily be made to pass a spine whack of any strength. The handles can be as stiff as you want, just by choosing good material. It is no more difficult to make it pass the test than fail it, just a matter of choosing an angle and knowing enough to choose it correctly. Manufacturing accuracy is less of a concern than you would think, as I have tried some really cheap lockbacks that don't fail.
Some fail really easy (small plastic Bucks and Gerber EZ-out), others I can't make fail with all my strength (Buck 110, steel handle Delica, FRN Delica, Cold Steel Voyager). The minibuck I could see preparing to fail just with hand pressure. More "good" ones in the "pass" list, but a Voyager is only about $35.
Another "pass" was literally a gas station knife. $3 for a Spyderco knock-off, possibly a Frost because it has that eagle on the handle. Not well made in the least, except the lock would not fail. I even put it in a vice and pressed down really hard. I didn't go too far because I was afraid the cheap steel might break.
I haven't tried the whack test on enough frame locks to judge the whole lock type, but I would be more worried about what Cliff calls the torque failure. That means you have the knife in your hand, and your hand twists a little. A fist doesn't just squeeze the slabs together, it squeezes in about equal from all directions. This can easily disengage almost any framelock I have tried except the stronges springs which make it ridiculosuly difficult to unlock on purpose (haven't tried a Strider). A lot of them you don't need too extreme of a test to see. Just pinch the blade, fist the handle tightly, and wiggle your fist around while putting closing pressure on the blade. This failure scares me because it is so dependent on the exact angle of your arm and hand movements. Careful cutting is not a problem, but a standard stabbing motion is at risk. You don't risk getting kicked out of a store for doing this, so I test every single folder I pick up for it, and I have to say the whack test is pointless for most of them because they fail the torque test under must less force than a whack test involves. Lockbacks don't have a torque failure problem because it just doesn't affect their lock format, unless the handle is so weak it could twist out of shape.