Master Key System

Master Key System

With the word master in the name, it sounds empowering. But, what exactly is a master key system and who benefits from them? More importantly, once you realize you want to set up a master key system, who do you call, and what are the steps to take to go about getting one installed and maintained?

What Is a Master Key System?

First, let’s describe what a master key system is. Simply put, it is a method of allowing one key to open more than one lock. More specifically, this one key is given to authorized personnel such as janitorial staff, realtors, property managers, or supervisors in a company. The purpose of the master key is to be able to have access to open several locks within the master key system that is set up specifically for your needs. For instance, a property manager who owns several apartment units within a building will want a master key which allows them to get inside an apartment for the purposes of maintenance or to show the apartment to a potential renter. Cleaning personnel use master key systems in order to gain access to otherwise locked and secured office space so they can get inside to clean. Another situation that requires a master key system may be that a manager may want control of keys given to his employees. Master key systems are used for hotel housekeeping staff, college or school campus locks, landlords, and any office or property that requires several keys.

How Keys and Master Key Systems Work

As a technical explanation, most master key systems use a pin tumbler style of lock. Pin tumbler locks are opened when a driver pin and key pin in a pin stack are raised above a shear line. This is done by inserting and turning the proper key. The key pins are varied sized, but the driver pin is a universal size which means, the key used to turn the lock must have the right set of grooves needed to lift the pins to the required height in order to unlock it. When a group of pin tumbler locks are converted to a master key system, a master wafer pin is added to go between the driver and key pin giving the pin stack two shear lines. One shear line is for the pin stack and one is above or below the line that allows the master key to work.

Once in place, the master key system will require at least two kinds of keys, the change key which is sometimes called a sub-master key, and the master key. The change key is the lowest level in the master key system and is intended to open only one lock or one type of lock. The master key is at the top level and is able to open every lock in the system. The system can go up in tiers to a Grand Master Key or even a Great Grand Master Key and beyond if necessary.

Master Key System

Pros and Cons of a Master Key System

One of the biggest pros to implementing a master key system is that it offers convenience along with reliable security in an affordable way, since they are inexpensive to install and not overly costly to maintain and upgrade. It eliminates the need to have a large, bulky key chain filled with tons of keys. It also gives you control over specific measures of security within the system. This system of key control keeps unauthorized employees, students, or visitors from entering spaces they are not allowed.

One of the only potential cons in a master key system is that pin and tumbler locks, which are the most common types of locks used, are easier to pick than other high-security locks. However, a knowledgeable locksmith professional will be able to walk you through methods that will increase your security, including installing a heavy duty secure lock on the outside of your building while using the master key system inside, using multiple cylinders, disk detainer locks, installing electronic controls or sidebars, using restricted keys or master rings, or even implementing separate master key systems for separate workgroups or sections of the building.


Before you install a master key system, talk with a qualified, skilled, and knowledgeable locksmith profession who will be able to recommend, install, and maintain the best system for your security needs.