The Concepts and Mechanics of Master Keying: Developing Master Keys Using Generic Types

Generics can simplify how we consider and work with incidental master keys.


By using Generics, locksmiths can easily develop master keys, or develop key characteristics from key bittings.

Generics can simplify how we consider and work with incidental master keys.

The last article (October 2004 Locksmith Ledger) demonstrated how to determine the power and characteristics of a random key in the master key system by decoding the key bittings. Generic Types were used to target how the key performed within the master key system and on a page, demonstrating the power of the key.

This article will demonstrate the reverse. A Generic Type will be selected from within a master key system, and the key bitting will be determined. To do this, you will need the Key Bitting Array (KBA, Figure 1) and a worksheet specifically designed to determine key bittings from Generic Types.

Before starting, let' s review what a Generic Type is.

In Figure 2, the KEEWERX template, the mechanism that creates Generics is px. This refers to the relationship to the number of change key bittings under the master bitting. In the KBA, this is expressed as rows for change key bittings and columns for the number of key bittings.

With most systems, there are four change key bittings under the system bitting in the KBA. When "p" in px equals 4 (the rows) and "x" equals the 6 (the columns), the results are 41+1+1+1+1+1 or 46 or 4x4x4x4x4x4, or 4096. This is the total amount of change keys that can be progressed in a standard six-pin master key system.

Other systems have five, six or seven change bittings under the master bitting, so the "p" in px accommodates all of these master key systems. As a system progresses, Generics are created. The term px can be used to express how the master key system progresses.

At p0, the beginning of progression is occurring in the first column. At p1, the first column is fully progressed and current progression is ready to start in the second column. At p2, the first two columns have fully progressed and current progression is starting in the third column. At p3, the first three columns have fully progressed and current progression is starting in the fourth column. At p4, the first four columns have fully progressed and current progression is starting in the fifth column. At p,5 the first five columns have fully progressed and current progression is starting in the sixth column. At p6, all six columns have been fully progressed.

Table 1 (page 36) reveals the creation of a Generic during steps of standard progression. There are only eight Generics Types: X0; X1;X2;X3; Y1; Y2; Z1; Z2.

For every three columns that progress, a new level of keys are created. The first three progressed columns create a complete hierarchy of key functions for each page of the master key system. The next three progressed columns create a hierarchy of key functions that occur within the pages of the first hierarchy.

This article is limited to Generic activity within 5- and 6-pin systems. Note that this process continues infinitely and that is there is a P7 (when dealing with 7-pin systems, etc).

Generic References for 5- and 6-pin systems are visually designed to reveal where and how the key functions. To do this, the Generic Reference is separated into two parts, a prefix and a suffix. We will examine the Generic Reference and its two components.

Consider the Generic Reference for a change key: X0X0. The first two characters represent the first Generic Type XO (the prefix), and the remaining two characters represent the second Generic Type XO (the suffix). Generic Types in the prefix position represent how the key functions throughout all pages. Generic Types in the suffix position represent how the key functions on a given page.

The numbers in both designate the power of the key. In the case of X0X0, the key operates keys on a single page, and can only operate a single change on a page (See Figure 2).

As a second example, consider the reference: X0X3. This key operates keys on a single page (p0=40), and can operate 64 (p3=43) keys on a page. Remember the numbers always reveal the power of the key (p3).

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