During the early part of the last century, the demand for larger and larger key systems began to outpace the capability of master keying principles. Colleges, institutions, and government buildings required more keying choices than the 4,096 theoretical changes of a conventional six-pin tumbler lock mechanism. A number of options began to appear in order to key larger and larger projects.
To resolve this problem, SARGENT utilized the development of sectional keys and related keyways. To develop sectional keying, conventional lock cylinder keys and keyways were modified in two ways. The first was to develop similar key and keyway configurations. These keys for SARGENT would become the Day Keys. They would be similar but different enough to prevent one keyway specific key from entering a different keyway. SARGENT decided to develop nine different keyways and keys for each of the sectional (multiplex) families.
To include multiple keyways under a single master key, it was necessary to develop key blanks that enter more than one keyway. SARGENT considered these Master Key Sections. They developed three levels of these Master Key Sections: Lower Level, Mid-Level, and Top Level. Each of the Lower Level Master Key Sections could enter three of the Day Key keyways. The Mid-Level Master Key Sections could enter two of the Lower Lever Master Key Section Groups, which included six of the Day Key Keyways. And the Top Level Master Key could enter the Mid-Level and Lower Level Master Key Section Groups which included all nine of the Day Key Keyways.
This development made it possible for one key to operate up to nine different conventional lock cylinder keyways. With nine different conventional lock cylinder keyways, the number of theoretical changes increased to 36,864. This was because each theoretical change could be used in each of the different sectional keyway lock cylinders.
Over time, the sectional keyway families were expanded to seven-pin lock cylinders creating a significant number of theoretical change keys.
The development of the sectional keying enabled large projects, such as multiple buildings, to be keyed using the same bittings. Although the same bittings were used, the different key and keyway configurations would stop key interchange.
For this article, we will use the SARGENT L Sectional Family. The nine Day Key conventional lock cylinder keyways are LA, LB, LC, LE, LF, LG, LJ, LK, and LL. The three Lower Level Master Key Sections are the LD, LH, and LM. The three Mid-Level Master Key Sections are the LDH, LDM, and LHM. The Top Level Master Key Section is the LN.
Lower Level Master Keys: LD, LH, and LM
• The LD Lower Level Master Key Sectional key blank can enter conventional lock cylinders equipped with the LA, LB and LC keyways.
• The LH Lower Level Master Key Section key blank can enter conventional lock cylinders equipped with the LE, LF and LG keyways.
• The LM Lower Level Master Key Section key blank can enter conventional lock cylinders equipped with the LJ, LK and LL keyways.
Mid-Level Master Key Sections: LDH, LDM and LHM
• The LDH Mid-Level Master Key Sectional key blank can act as a higher level master key section for the Lower Level Master Key Sections LD and LH, as well as enter conventional lock cylinders equipped with the LA, LB, LC, LE, LF, and LG keyways.
• The LDM Mid-Level Master Key Sectional key blank can act as a higher level master key section for the Lower Level Master Key Sections LD and LM, as well as, enter conventional lock cylinders equipped with the LA, LB, LC, LJ, LK, and LL keyways.
• The LHM Mid-Level Master Key Sectional key blank can act as a higher level master key for the Lower Level Master Keys LH and LM, as well as, enter conventional lock cylinders equipped with the LE, LF, LG, LJ, LK, and LL keyways.
The Top Level Master Key Sectional key blank, the LN, can act as a higher level master key for any or all of the Lower Level and/or Mid-Level Master Keys. The LN Master Key can enter the LA, LB, LC, LE, LF, LG, LJ, LK, and LL Day Key conventional lock cylinder keyways.
CAUTION: Because higher level Master Keys can enter more of the different conventional lock cylinder sectional keyways, it is extremely important to never use a higher level key blank when cutting a Day Key or lower level master key. Cutting a key on a higher level blank than necessary undermines the master key system and can lead to unintentional interchange and increased liability.
SARGENT Lock Company uses a simplified key blank numbering system that includes the keyway identification as part of the numbering system. The blade length is also part of the numbering system making it easier to know the key blank keyway and number of pins used in the keying system just by looking at a SARGENT key blank.
The SARGENT key blank number is two parts: the key blank and the key section. For the conventional lock cylinder, a five pin key blank for the Day Keys is number 275. A six-pin Day Key blank is number 6275, and a seven-pin Day Key blank is number 7275.
The part numbers for Day Keys also apply to single section Master Keys. For the conventional lock cylinder, a five pin Master Sectional key blank is number 270. A six-pin Master Sectional Key blank is number 6270, and a seven-pin Master Sectional Key blank is number 7270. The Key Section is the keyway. For the L Section, the nine conventional lock cylinder keyways are LA, LB, LC, LE, LF, LG, LJ, LK and LL.
The key blank number is the combination of the key number and the key section. For example, a SARGENT six-pin Day Key blank having the LA key section is identified as 6275LA. A SARGENT six pin Master Key blank capable of entering the LA, LB, and LC keyways is identified as 6275LD.
Chart 1 (below) is a cross reference of the SARGENT L Section six pin key blanks starting with the nine Day Keys, then the Lower Level, Mid-Level, and the Top Level Master Keys.
IMPORTANT: Be aware that as lock cylinders begin to wear through use, the keyway can begin to expand. It is extremely important to make sure the keys chosen for a sectional keyway master key system are of a size that there will not be the ability of a one key section key being able to enter a different lock cylinder plug key section.
SARGENT factory cut keys have specific identifiers stamped into the bow. For example to identify a factory cut key, it will always have the chevron symbol stamped into the reverse side of the bow. Factory cut day keys or change keys have the bitting stamped into the bow. Factory cut Master level keys do not include bitting numbers, however, they have the key set stamped into the bow.
Sectional key families are still a viable way to provide a significant number of theoretical change keys for a large keying project.
For the purpose of this article, we will be using SARGENT terminology.
Key Blank Key Section - Change key (Day Key) in a single section (one keyway) or multi-section (more than one keyway) master key system - or master key in a single section (one keyway) master key system (any level)
Master Section – Master Key that passes more than one section (keyway) in a multi-section or multiplex master key system (master key system that has more than one keyway). It is important to note that only the key blank is available in a master section. Cylinders and plugs are generally available in a single section only.
Plug Key Section – The keyway of the plug or cylinder
For more information, contact your local locksmith wholesaler or SARGENT Manufacturing Company, 100 SARGENT Drive, New Haven, CT 06536-0915. Telephone: 800-727-5477. Fax: 888-863-5054. Web site: www.sargentlock.com.
Denise Conine, AHC, CRL is an end user specialist, trainer and key system specialist with ASSA ABLOY Door Security Solutions of Southern California. She has been in the locksmith industry for 23 years.
|Lower Level MK Section||6270LD||O1007LD||6270LD-NS|
|Lower Level MK Section||6270LH||O1007LH||6270LH-NS|
|Lower Level MK Section||6270LM||O1007LM||6270LM-NS|
|Mid-Level MK Section||6270LDH||O1007LDH||---|
|Mid-Level MK Section||6270LDM||O1007LDM||---|
|Mid-Level MK Section||6270LHM||O1007LHM||---|
|Top Level MK Section||6270LN||N1007KMA||6270LN-NS|