allow us to create new bitting
combinations for the needed
cylinders. Best choice would be
from the third or fourth columns.
The system information
should be copied to a System
Card, as you see in Figure 2.
Note that the “hold position” is
shown in the KBA and in the bitting section.
Figure 3 shows the progression of Change Keys on the
reverse side of the System Card.
Seven of the 64 bitting combinations failed the MACS test,
which leaves fifty-seven ( 57) usable Change Key bittings.
We should have no great fear
of new bitting combinations creating a problem in this system.
A “Pinning Matrix Card” could
also be made for this system,
using information from the KBA.
It will define the pin stacks of all
cylinders in this system. Figure 4
shows the Pinning Matrix Card
for this system. The Title Block
shows the location of the system,
and states that this is a “recon-
structed” system, built over
Schlage SC-1, 5-pin cylinders.
Complete the Matrix Card,
1 From the Odd and Even
nature of the TMK bittings,
we find only Even Change Key
bittings in position number one.
Position number two is a “hold”
position, so the #7 depth is the
only depth that is defined. Posi-
tion number three is Even so all
Change Key Bittings are Even.
Position number four is Odd so
all Change Key Bittings are Odd.
Position number five is Even so
all Change Key Bittings are Even.
Number the Matrix pin-stack
representations to show this.
2 The representative Pin Stack
diagrams are each numbered
to define the pins in the stacks.
Combinating pins are chosen to
satisfy the Change Key bitting
and the TMK bitting for each
position of the key. Number the
pin-stack elements (bottom pin,
master pin and driver) of each
pin-stack to show this.
Position number one of the
key will allow only Even numbered cut depths. They are: 0,
2, 4, 6 and 8. The first column of
the matrix is numbered: 0, 2, 4, 6
A zero (0) depth cut in the
Change Key shows: a #0 bottom