Associated Locksmiths of America

 

Masterkeying

Masterkeying is a way to combinate a group of locks or cylinders such that each is operated by its own change key as well as by a master key for the entire group. Our key systems utilize the Standard Key coding System illustrated in the following paragraphs. Standard Key coding is an industry standard and uniform method of designating all keys and/or cylinders in a master key system. The designation automatically indicates the exact function and keying level of each key and/or cylinder in the system, usually without further explanation.

2 Level System

To Specify a Simple Master Key System (2 Levels of Keying) The master key symbol consists of Two letters, such as AA. The change key numbers are added to the master key letters. The numbers come FIRST: 1AA, 2AA, 3AA, etc. When locks are required which are not operated by the master key or other change keys in the system, they are referred to as “single keyed” and given symbols SKD1, SKD2, etc.Two level keying diagram

3 Level System

To Specify a Grand Master Key System (3 Levels of Keying) The grand master is assigned any One letter, such as A. The master keys under this grand are assigned Two letters, the first of which must be the same as the grand: AA, AB, AC, etc. are all masters under grand A. Masters BA, BB, BC, etc. are all under grand B. Caution: Do not use the letters I or O or Q because of possible confusion with the numerals 1 and 0, respectively. Change key numbers come after the letters, e.g., AA1, AA2, AA3, etc. For master keys beyond AZ, insert a numeral between the letters to designate which pass through the alphabet they represent. A2A through A2Z represents the second pass of masters under grand A. A3A, through A3Z would be the third. Change keys under these masters have the numbers suffixed in the usual way A2A1, A2A50, etc. If the cylinder is to be operated by its change key and nothing lower than the single-lettered GMK, the change number is added to the GMK symbol. This is illustrated by the example A1 in the schematic shown. When locks are required which are not operated by ANY master keys or other change keys in the system, they are referred to as “single keyed” and given symbols SKD1, SKD2, etc. When all higher levels of master keys are to be disallowed, suffix (NMK) to the symbol of the change key which it is to operate. This means “not master keyed” and can be applied to any level in the system. Cylinder AA1(NMK) is operated by AA1 only. The AA master and A grand are blocked from operation. Cylinder AA(NMK) would be operated by the AA master only. Grand A does not operate.Three level keying diagram

4 Level System

To Specify a Great Grand Master Key System (4 Levels of Keying) The great grand master key is assigned the symbol GGM. The rest of the symbols are the same as those in 3-level systems: The GMKs are assigned single letters, e.g., A,B,C,D, etc. Caution: Never use X for a grand master key due to the confusion which will result with cross keying symbols. Masters under each GMK are assigned two letters, the first of which is the same as its respective grand master key. Change key numbers come after the letters. Changes under the grand (A1, B1, etc.) and masters beyond AZ are handled exactly as in the 3-level system already described. For changes directly under the GGM with no intermediate level masters, the change number is added directly to GGM as shown by the example GGM1 in the schematic. When locks are required which are not operated by ANY master keys or other change keys in the system, they are referred to as “single keyed” and given symbols SKD1, SKD2, etc. When all higher levels of master keys are to be disallowed, suffix (NMK) to the symbol of the key which is to operate. This means “not master keyed” and can be applied to any level in the system. Cylinder AA1(NMK) is operated by AA1 only. The AA master, A grand and GGM are all blocked from operation. Cylinder AA (NMK) is operated by the AA master only. Grand A and the GGM do not operate. Cylinder A(NMK) would be operated by the A grand only, without the GGM.Four level keying diagram