when reading the tumblers.
An exploded view of the
Cylinder Plug and combinating
wafers (tumblers). Each tumbler
is stamped with its bitting depth.
A number Four is the shallowest
depth and a number One is
the deepest. Shallow and Deep
somehow loose their definition on
side milled keys. A Number Four
(#4) depth is closest to the center
of the key. A Number One (#1)
depth is closest to the edge of the
key. Left and Right tumblers are
identical. (Figure 19)
Tumblers at the top of the plug
are: Right – Left – Right – Left –
Right – Left, bow to tip.
Tumblers at the Bottom of
the plug are: Left – Right – Left
– Right – Left – Right, bow to tip.
Their depths are shown above
their designations. Left Depths
have been underlined and Right
Depths have been circled in the
Depths for the Left Track are:
3 – 1 – 3 – 1 – 1 – 3.
Depths for the Right Track are:
1 – 3 – 3 – 2 – 4 – 2.
Remove the tumblers, one at a
time, to read and record the depth
designations. Remove and replace
each tumbler, after recording
its’ depth. This will avoid the
possibility of mixing the tumbler
positions and misreading the
An operating key for our
cylinder. Study the profile cuts
of the Left and Right tracks, to
see the depths. They are labeled
from bow to tip, and called out as
right and left track. Understand
that only half of the cuts are used
on either side (top or bottom) of
the key blade. This allows the key
to be reversible in the cylinder.
When holding the key by the
bow, and with the tip pointing
away from you, the Left track will
be on the left and the Right track
will naturally be on the right.
Cuts are always read Bow to Tip.
There are only four depths in this
configuration, so sight-reading the
cuts (bitting) of the key is easy.
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