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How Master Key Systems Work

May 4, 2016

How Master Key Systems Work


Imagine that you are staying in a large hotel that has 100 rooms. Each room has a key for access, which you are usually given when you check in. As you check out, you need to give the key to the reception. During your stay, you keep your key with you at all times, yet, the housekeeping staff are still able to get into your room and clean it up when you step out. One day you meet them doing so, and to your surprise, they are using one key to open all the doors to the different rooms. When you try to do the same, it simple doesn’t work. Why is that? The reason lies in the mysterious Master Key system.

A master key is a key that is designed to make it simpler for one to gain entry into a range of situations. These include being able to access a range of units, like in the hotel, or all the doors in the home or a residential property, using only one key. Wondering how such a key works? First, you need to understand the way that a lock works. You will find the following elements: –

Pins – Most keys will have a few pairs of pins for the lock to work. In the pairs, one of the pins will be on top, while the other shall be at the bottom. In locks for master keys, there are three pins.

Shear Line – This is the space within the lock where you put in the right key, and the pins are pushed back. When this happens, there is adequate space to turn the key.

Key Notches – These are the uneven edge on the key. There are numerous notches there and these are meant to go with the pins which are within the cylinder.


The Pin and Tumbler Lock

These are the locks which are most often linked to master key systems, and they will usually have a range of pins that are different lengths. They are found in pairs within the shaft of the lock. In the event that there is no key in the lock, then the bottom pin remains inside the central cylinder plug. However, the upper pin can be found halfway inside the plug, with the other half being in the housing.

As you slip a key into the lock, inside, there are notches which are on the key. These will push the pins at varying levels. When you put in the wrong key, you will end up pushing the pins partly but not completely. What happens is that the pins at the top are still in the plug a little bit, while also in the housing. When you are using the right key, the result differs as all the pins are pushed such that they line up perfectly.

A master key will have three pins within the lock. What this means is that when the key is turned, it actually creates a gap which is at the shear line. The result of this is that the key being turned in the lock will make it open. The master key is able to vary in its length, which makes it easier for this key to open any type of pin and tumbler lock.


Creating a Master Key System

One master key means that you can open several locks with one key. However, a system is a little different. Here is an example to make it clearer: –

Imagine that you work in a medical clinic. As a doctor, you need to have access to all the rooms within the clinic. Directly underneath you in regards to authority is the Pharmacist. They need to have access to all the rooms with exception of your office. The pharmacist works with nurses, who need to gain access to their office and the office for supplies, but not the offices of the pharmacist or the doctor. Finally, you have the person who is in charge of the supplies, who is not meant to gain access to anywhere but his office.

In this instance, you will need a key for the doctor which is all access, we shall call it level 1. At level 2, there is one restriction. At level 3 there are two restrictions. At level 4 there are three restrictions. What this means is that the person at level one is saved from having to carry around a large bunch of keys as they are able to access everything that they need. At level three, the key that they have can open two doors which is enough for them.

Having this type of access and restrictions is what makes up the Master Key system, and this also explains how it is able to be controlled for the long term.


Added Security

Some people remain anxious about using a master key system. Although the system is meant to make things more convenient, it also means that if a person gets a hold for the key, there would be a real security problem. To deal with these fears, it is recommended that one gets a complex lock which can be much harder for a potential criminal to decode.

In addition, it is suggested that side bars be added to structures so that the security of the locks can improve substantially. Anyone who is installing any programmes or systems needs to ensure that they are fully understood.


There is one main reason that people want to use master keys and that is convenience. The pull to be able to open a range of doors with just one key continues to grow. There are different types of master keys as has been ascertained by the example on the medical clinic. It is still possible to retain some control with a master key, and decide which doors are to be opened by what. It is better to go for a master key system that is complex than one that is simple for long-term safety.

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