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What is a Master Key System and How a Master Key Work?

Views:0     Author:D&D Hardware     Publish Time: 2021-06-11      Origin:D&D Hardware

What is a Master Key System and How a Master Key Work?

What is master key?

A master key is a key which will open all the locks in a set, even though each lock has its own different key.


Master Keying


Keying is a term within the hardware industry that is used to describe the arrangement of the keys in a building, assigning them into groups in order to limit the doors that personnel will be allowed to operate by key.

It is important to understand that the purpose of a master key system is convenience. It would be cumbersome for an owner to carry a key for all the locks in a building or group of buildings. Master keys must be carefully controlled as their loss could require all of the locks to be re-keyed.

There is a common misconception that a master key system implies greater security. However, the highest degree of security is found in a cylinder that is operated by its key and no other. Therefore, the more complex the key system becomes the less security it provides. 

Most pin tumbler locks can be master keyed. Because of their basic design-the number of biting steps and the accuracy of the biting-pin tumbler cylinders have more key changes available than other types of lock mechanisms.


How a Master Key Works


Master Keyed refers to a group of locks that are operated by their own key (a.k.a. change key) and by another key that operates all of the locks in a space or building. A master key system is one that provides a magic key that opens all locks.

The essential difference between an ordinary pin tumbler cylinder and a master keyed cylinder is the use of master pins, also called split pins. A master pin is an additional top pin, usually shorter, which is inserted between the bottom pin and the top pin. In each pin chamber where a master pin is located, a second shear position is created. The cylinder will operate equally well at either shear position. Thus, different key bit-tings can be used for each position where there is a master pin.

Notice that two keys, each with a different key biting, can operate the same lock. One key is called the change key, and usually operates only one lock while the other key, called the master key, is arranged through the use of master pins to operate all the locks in the system.


Below illustrations show a cutaway cylinder containing pins to allow a master key (687846) and a change key (455221) to operate the cylinder.

lock cylinder pin 

The following are all the key changes that will operate this same cylinder.

 lock cylinder master key system

Note there are 64 different keys that can operate this cylinder, although all that is wanted is one change key and one master key to do the job. This means that when all 6 chambers contain master pins for every change key established under one master key, 62 others (64 minus 2) are eliminated! 

 double lock cylinder single lock cylinder


key management function

Guess this can help you under the master key system better.


D & D's lock cylinders have passed strict EN1303 and DIN 18252 / 09-1999 safety tests.The lock cylinder has passed 100000 tests.  Various styles of mortise locks are suitable for different public places such as public buildings, industrial places, medical buildings, and education places. and we can provide management system lock cylinder door configuration solutions.

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