The Warded Lock
The Warded Lock
The warded lock’s basic design was created by the ancient Romans. The basic principle behind its
operation is a series of "wards"
(projecting obstructions) that prevent all but the
proper cut key from being rotated inside the lock. These obstructions have been placed
in the
path of the turning of the bit portion of the key. This type of lock utilizes a key that has been
notched in a way that it clears all the
wards, but is still able to turn the bolt. These locks
are easy to recognize. They are the "classic" antique lock that you may still find in
old
houses.
_______ blade (stem) ##### handle (bow)
/ \ ########
\ / ################################# ##
| |
#### ### ########
/ \ #### ### #####
/ \ ####
/ \ bit a warded key for a two-ward
lock
/___________\
warded key lock entrance
The number of wards in
the lock can vary, but normally two is the minimum. When a user inserts a key into the warded lock,
the
metal obstructions inside the lock allow only the proper key to be inserted. The key
bittings allow the key to turn in a circular motion,
opening the lock through one of four
different mechanisms:
1. The key lifts a detent lever while throwing the bolt,
providing deadbolt action. (Deadbolt action means that the bolt is secure
against end
pressure.)
2. The key moves a bolt whose locked or unlocked position is maintained by
the action of a humped flat spring in two notches on
the bolt.
3. The key moves
directly against the latch tail of a latchbolt, or does so through the action of a floating
lever.
4. The key inserts between two springs and wedges them apart as it is turned.
(Usually only in warded padlocks)
Picking
These locks offer only token
security to the user. Besides being easy to circumvent, the warded locks offers only about fifty
alternate
keying combinations. Picking them is generally regarded as trivial. All that is
required is to bypass the wards and move the bolt into the
unlocked position. This can be
accomplished by using a pick known as a "buttonhook". To make your own buttonhook pick,
use a pair
of pliers to bend a six inch section of coat hanger into a warded key shape as
below:
########
### ##
################################# ##
# ##
##
### ## #
#####
The wire should be thin enough to pass into the keyway
while avoiding all the wards, but stiff enough that it can still manipulate the
bolt to open
the lock. Though you may have to make a "large" and a "small" warded lock pick,
the same principle applies.