by Olson Burry » 23 Jun 2009 0:45
Hello Timbo,
False sets occur when dealing with security pins.
The easiest way I can think of to describe it right now is if we try and picture a 3 pin lock, with 2 spool pins and 1 regular pin. Spool pins are shaped like a capital "I" (I as in me) instead of your regular | shape.
When the spools are at rest, the middle of your "I" shape will be at the sheer line and consequently will not bind whilst your regular pin will. (normally)
So you push the regular pin up to sheer and the plug rotates, slightly, because there is space for the edge of the sheer line to move in to the middle of the spool pins. That's your false set.
At this point you have to think about tension. You're going to have to push the bottom of one of the spools past the sheer line and to do that the plug will have to be allowed to rotate backwards a little bit to let the fat end of the spool past. You'll feel the plug want to turn backwards when you apply pressure to the key pin under the spool so long as you're not applying too much tension to miss such a subtlety.
Hope that helps a bit, I'm sure some pics would help more but I don't have the time right now.
Good luck!