Find the Key Bittings
from a Generic Type
To maintain consistency, the Key Bitting Array (KBA) and the Generic example used in the last article will be discussed: Y2X2. Refer to Figure 3 as the worksheet titled: "Develop a Master Key (6-pin)."
The Key Bitting Array was filled out using the provided KBA in Figure 1.
As shown in "Step 1," the selected Generic (Y2X2) was split into two equal parts and entered on the "A" and "B" line.
In "Step 2", any cuts in common with the TMK were identified by following the instructions: The part of the Generic that was entered on the "A" line, "Y2" is located to the left (row header) of the Alignment Chart. Any 6, 5, or 4 that appears on the same line in the Alignment Chart is circled. In this case a "6" and "4" was circled.
The part of the Generic that was entered on the "B" line, "X2," is located to the left (row header) of the Alignment Chart and any 3, 2, or 1 that appears on the same line in the Alignment Chart is also circled. In this case a "2" and a "1" was circled.
In "Step 3" the Sequence Of Progression (SOP) from the KBA is transferred down into cells provided to the right of the step. The number in each cell is compared to numbers circled in the Alignment Chart. If a circled number in the Alignment Chart matches the number in the cell, the number in the cell is also circled.
In "Step 4", check each cell in the "Step 3" to see if it is circled. If it is circled enter the number from the TMK line in the KBA that appears in line with the same column. Do this for each cell. In the example the first two cells in "Step 3" were not circled, so nothing was entered into the cells in "Step 4". The last four cells in "Step 3" were circled so the numbers that appear on the TMK line of the KBA were entered into each cell of "Step 4."
Any change key is entered into the cells of "Step 5." This is usually a change key that is being used for a specific master key project in which a master key is needed.
The final step, "Step 6," integrates both the selected change key ("Step 5") and the cells that were entered in "Step 4." For each cell to the right of "Step 6," enter the same number, in the same position, from "Step 4". If the cell is blank, enter instead, the number from the cell in the same position from "Step 5".
When completed, the key bitting for the master key, Y2X2, appears on "Step 6."
A blank worksheet (Figure 4) is provided so that you can use this procedure to determine master keys for your own master key systems. Although the worksheet seems to work like a magician's number trick, it simply relies on the tried-and-true premises already established in Standard Progression Format (SPF). Each step in the worksheet is designed to "guide" the locksmith through a process that enforces SPF rules.
A crucial step in the worksheet is guiding the locksmith through the implementation of the Alignment Chart. The chart is deceivingly simple, even though much research has gone into its creation. The Alignment Chart is a table that notes when and where TMK bittings will appear in a targeted key. It charts the evolution of master keys as keys sequentially progress. The Alignment Chart in Figure 3 is designed for both 5- and 6-pin systems.
Developing a Key Bitting Array when it doesn't exist
Essential to good master keying procedure is the establishment of a static Key Bitting Array.
Locksmiths tell me many of their existing master key systems do not come with a KBA, rather they exist in the form of pages of records. Lock manufacturers often provide these pages to locksmiths, not as a complete "book" but as the part of the "book" that the locksmith currently needs. For these locksmiths, there is a process to determine the original Key Bitting Array.
When information is not readily available to complete the KBA, a decision has to be made. If support regarding the existing system is ongoing, you will need to discuss the completion of the KBA with the source of the existing system.
If no updates are anticipated, the KBA can be carefully filled-in by honoring the rules of Standard Progression Format.
Here are the rules to follow:
Regarding the sequence of progression, each number represents the order in which the columns progress; therefore, numbers have to be sequential and cannot be repeated in the SOP.
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