Specification) specification is four
( 4), using OEM pins.
The first step in any system is
to review the Basic Rules of Master Keying. Figure 1 shows the
Basic Rules of Master Keying.
Rule Number 1 will be
observed by the proper construc-
tion of the KBA. (Separate Mas-
ter & Change Key bittings)
Rule Number 2 will be
observed by choosing Odd or
Even numbered bittings in the
columns of the KBA.
Rule Number 3 will be
observed when we “weed” the
bitting list for MACS violations.
(MACS will be
5, if using universal bottom
will be observed, but
“Odd or Even
Bitting Array) chart is shown in
Figure 2. We need to choose a
TMK bitting, to begin.
The bitting is best chosen using an “Odd - Even - Odd - Even -
Odd” or “Even - Odd - Even - Odd
- Even” arrangement. (This is a
The TMK bitting will be
entered above the heavy line, and
the remaining bittings, to be used
in the Change Keys, will be entered below the heavy line. They
can be entered in any desired
order, from top to bottom, observing the Odd or Even choice
in the TMK bitting. The chart
will accommodate six positions
on the key. We will only need the
first five for this system.
Figure 3 shows a completed
KBA. The TMK was chosen
pretty much at random.
• Position #1 of the TMK is a #3
depth. This is an Odd number.
All of the bittings in this column
must also be Odd. Bittings: 1, 5