patented on Feb. 11, 1936 and
was quite an advanced lock for
its time. If you have this lock in
your collection check to see if it
is master keyed.
In figure 25, the lock on the
left is master keyed. Note the
wide keyway. The lock on the
right is standard keyed. If you
look into the keyway of the master keyed lock you will see four
sets of double bitted tumblers.
The master key uses the outer
steps and the change key uses
the inner steps.
Figure 26 shows the wider
master key. These master keyed
Dudley locks were usually made
for the government and are
marked US on one side.
Two Separate Keyways in
the Same Plug
At first, this concept might
seem nearly impossible. However, King Lock Co., Chicago
made a lock that is very similar
to today’s Chicago locks. They
used blade tumblers which are
just many disk tumblers placed
next to each other, (Figure 27).
Figure 28 shows standard and
master keyed lock plugs. To accomplish two separate keyways,
King had a large plug which accommodated large disk tumblers.
The disks actually had two separate holes in the disks. One hole
passed the operating key and
the other the master. Obviously
the master disk holes all had the
On April 22, 1922 Junkunc
(American Lock) Co. patented
an unusual designed lock mechanism. They called it “Grip Tumbler”. It consisted of a series of
slides which directly locked a
padlock’s shackle. This lock is
actually a push key lock. Figure
29 shows the lock and its keys.
Figure 30 shows the bottom
of a master keyed and standard
padlock. The lock on the left has
two separate keyways. The top
one is for the operating key and
the bottom one is for the master
key. Both of these keyways operate the same sliding levers.
About the Author: Robert
Dix is President of the “American
Lock Collectors Association” and is
the Editor of the “Journal of Lock
Collecting,” a bi-monthly publication of the American Lock Collectors Association. He has also been
inducted into the “Lock Collectors
Hall of Fame, and is a leading
authority of antique and collectable locks.
You can contact him at:
Continued from page 30
25. The lock on the Left is Master
26. Standard Key on Left Master
key on Right.
27. King Locks.
28. Lock on Right is Master
29. American Push Key Lock.
30. Master keyed with Two
Keyways on Left.