Master Key System Function M&N Locksmith Chicago IL

How Does a Master Key System Function?

Master key is a concept that many people find intriguing. The question that how can one key opens multiple front door locks confuses people. This article is an attempt to take a deeper look into the mechanics behind the master key system without going into the boring details. After reading this article, you should be able to make an informed decision when finding a master key system, Chicago, IL.

The key component of a master key

Before I give you the key component of a master key system, I must mention that in this article we will focus on the pin and tumbler locks only. I have focused on this type. This lock type is the most popular in use today. The design of the pin and tumbler is fairly simple. Each lock contains a series of pins. When the pins are locked with the key, the movement of the bolt present inside the lock stops.

The components of the lock include key pins also called bottom pins, and driver pins, also called top pins. The bottom pins are designed to correspond to the cuts of the key and the top pins are placed between the key pins and springs of the lock to block the rotation of the inner piece of the lock, called the plug.

What makes an ordinary pin and tumbler lock a master key lock is the addition of pins called master wafers. For the lock to open, the master wafers need to line up. We will look at all the components of a master key later in the article. But before that let’s see the different types of key systems related to the master key.

Different types of master keys

When looking for a master key system, Chicago, IL, keep in mind the different types of keys in a master system. Here is a breakdown of the keys according to how much access they grant to their user.

Change key: A change key is different from the master key because it can open those entry door locks that are identical or just one lock, like the master lock. You can use the master key to open the lock that the change key opens.

Master key: as described before, the master key is a key that can open more than one locks. Sometimes master keys are called MK for short.

Grand Master key: In a large-scale setup, you may have a separate master key for each section. In this case, the key that opens all the master key systems is called the grand master key or GMK for short. This classification does not end here. The next level up is the great grand master key; which works on all the locks in the grand master system.

Three main parts of a master key system

Shearlines: The master lock system has two shearlines. The regular shearline is the line going through the middle of the lock. When you enter the key into the lock to align the pins, the shear line makes the space that you need to turn the key. I have explained the second shearline in detail below.

Pins: As mentioned before, there are both bottom and top pins. The top pins are above the normal shearline of the lock; the bottom ones are below the shearline. Both pins are in the shape of thin cylinders.

Master wafers: The regular pin system consists of split pins. The master wafer is a thin piece placed between what would normally be two separate pins. The wafer is attached to both pins so the whole unit is a single please unlike the other pin system, where you a top and a bottom pin.

So how does this change how a lock is opened? When you enter the key underneath the pins; the bottom pin’s edges match that of the key; the lock will open at the space created between the split pins — the shearline. If we have a lock system where we have split pins and wafer pins. We have a system with two shear lines. The second shared line is created below the master wafer pins because these pins cannot be split.

Two shearlines means two ways of opening the lock. When you have multiple locks with the wafer system design you have, you can use the same master key to open all of the locks. The number of master wafers varies from lock to lock. You can find a master key system Chicago, IL, that has many master wafers and locks that have just one. Hopefully this information will give you some talking points done discussing with the locksmith.

Pros and cons of master locks

Pros: Master locks can make life easier for you by reducing the number of keys you have to worry about. Instead of a bunch of keys that you have to go through to find the right one, you always have the one that’ll open all those locks. This convenience is especially handy in emergency situations. Also, they come in handy if you, your roommate, or a colleague lose the regular key.

Another big benefit is access control. Many businesses like to provide access to certain areas based on the seniority or designation of the employee. The master key makes this possible. It also enables businesses to reduce the number of keys that they have to distribute.

Yet another convenience is the easy storage of keys. If you have to carry around a bunch of keys then, you’ll appreciate having just one key. Because you can easily store it in your wallet or slide it into your pocket.

Cons: While the convenience of a key system is undisputed, there are some risks that you should check before looking for a master key system Chicago, IL. The possibility to access multiple areas can go against you if the keys end up in the wrong hands.


Overall, the unique system of master keys offers several advantages. If you want to learn more about this system, contact M&N Locksmith Near Me Chicago IL for a free consultation.

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