Simply put, a master lock is designed to give a single person access to every lock within a group. There will be one key, a master key, which can open every lock in the set, while the other keys will only open an individual lock. Master locks and keys are incredibly common in apartment buildings or businesses where the manager needs access to every apartment or individual office without allowing someone in one apartment to enter the home of a neighbor.
Understanding How Keys Work
In order to get a thorough understanding of how master locks work, you must first understand how a standard key works. It uses what is known as a pin and tumbler lock in which the lock contains many pins that vary in length and are divided into pairs with a shaft running along the plug’s central cylinder. This means that if there isn’t a key in the lock, the bottom pins will be within the plugs while the top ones will be half in the housing and half in the pin. When the key is inserted, its notches move the pin pairs, and the right key will make it so each pin pair joins along the shear line, the space where the housing and cylinder connect.
How Master Locks Work
Master locks are similar to standard pin and tumbler locks, but slightly different in that they are designed to work with two different keys. For this to work, some pin pairs contain a third pin, the spacer or master wafer. This combination of three pairs allows for two different combinations that will create a gap along the shear line. One key will create this gap above the master wafer while the other will do so below it.
Master Key Vs. Change Key
The two keys involved in a master lock are known as the master key and the change key. The change key is the one that works for an individual lock, such as your particular apartment within a building or a specific office. The master key is the one that will work with every lock in the group.
Why Use Master Keys
Master keys are especially popular in apartment or office buildings, as they prevent the need to carry dozens (or hundreds) of keys around with you at a given time. Instead, you simply need to have the master key on hand and will be able to enter every area. It also works well in factories or production areas where some people need access to every part of the building, while others only need access to a portion.
Installing Master Keys
While some people may feel that they are up to the challenge of attempting to install the master lock and key system themselves, this is best left to a professional locksmith. The potential for errors increases dramatically when installing a master lock compared to a standard one, not only because each lock needs two keys that can open it, but also because the same key must work in dozens of different locks. Locksmiths have the experience, training, and tools to correctly install your master lock system on the first try, so you don’t have to worry.