A pin tumbler uses pins of the same length to prevent the lock from opening without the correct key.

A pin tumbler uses pins of the same length to prevent the lock from opening without the correct key.

• A. True
• B. Sometimes
• C. Not specified
• D. False

Answer: (D)

Pin tumbler security comes from matching the heights of a mixed set of pins so that only the correct key raises every bottom pin to the exact height needed for the seams between bottom and top pins to sit at the shear line. If all the pins were the same length, the alignment would no longer depend on the varying key cuts; a key with uniform depths could lift all pins to the same height and align all seams, allowing the plug to rotate. In short, having identical pin lengths would not prevent opening without the correct key and could, in fact, make it easier to defeat the lock.

Pin tumbler security comes from matching the heights of a mixed set of pins so that only the correct key raises every bottom pin to the exact height needed for the seams between bottom and top pins to sit at the shear line. If all the pins were the same length, the alignment would no longer depend on the varying key cuts; a key with uniform depths could lift all pins to the same height and align all seams, allowing the plug to rotate. In short, having identical pin lengths would not prevent opening without the correct key and could, in fact, make it easier to defeat the lock.