by lockman » 27 Nov 2003 17:12
The two shear lines make BEST (SFIC) locks hard to pick. It's random chance whether a pin will set at the control shear line or the operating shear line, and if you get 6 pins at one and 1 one at the other, it won't open even tho it will seem to be picked.
They're also made to VERY TIGHT tolerance and some of the newer ones have spool pins. Even w/o spool pins they are a and a half to pick.
If its master keyed, there's twice as much chance of a given pin setting at the operating shear line, but the odds are still against you. Sometimes it will pick anyway if there's more friction at the operating core than the control tab, or you could use a special torque wrench that lets you pick the control tab alone.
I suggest you follow the linque someone posted above to Matt Blaze's web site.
Dr. Lockman