Master pins/wafers are used to pin up locks in order to allow a master key to work as well as the change key. If your'e the school janitor you have the master key to all the classrooms, but if you're a teacher, you only have the change key which only opens your classroom. There are sub masters that only open a dorm room floor, grand masters that will open a whole dorm or office building, and great grant masters that will open a whole campus or office building. This can get very complicated and busy, but in general, the pin stacks in the lock will have multiple key pins and master wafers above the key pins in order to allow several different keys to work in the lock.
your typical home lock has 1 shear line, meaning only 1 possibility for the split between the key pins and driver pins to occur. If you introduce master pins/wafers into the pin stacks, you now have at least 2 shear lines per each pin stack that has a master pin/wafer installed. Now you have more chances to pick the lock because you have more possibilites of creating a shear line.
Our friend Schuyler does a nice animation:
http://www.youtube.com/watch?v=8U6rdI_uG2cOur friend Kokomolock does a very good technical explanation:
http://www.youtube.com/watch?v=CQNf7S7MQFYhope this helps, if not, watch Schuyler's entire 24 video set and you'll be picking like a champ in no time!
Squelchtone
