What is a Master Key System?

A Master Key System is a hierarchy system where each lock in an organization can be unlocked by an individual ‘change key’, as well as a ‘master key’ that can open them all.

At a very simple level, think of a household of a Mom and Dad with two kids, Johnny and Jenny. Johnny has his own bedroom that Jenny is definitely not allowed in. Jenny has posted a sign that says, “ no boys allowed. Each Johnny and Jenny have access to their own bedrooms, but they are not allowed to enter the others’ territory.

We all know that Mom and Dad’s ‘Master’ bedroom is off limits. But Mom needs to enter Johnny’s room to pick up his stale socks and spray a bottle of febreeze throughout the room. Jenny forgot her ballet shoes that she will need immediately after school for dance class.

Let’s climb the family tree a bit up to Grandma’s house. Grandma and Grandpa spawned more than just Mom and Dad. Mom and Dad have siblings and the siblings also have children. The Siblings, however many there may be, create separate ‘households’, if you will.

What is the difference between the different types of keys?

Change keys?

Change Key (CK) – This key will only operate one lock or group of locks in a series that are all keyed alike.

How many change keys are possible?

While the Change Key is the lowest level of the Master Key System, there can be several different groups of Change Keys.

Consider Johnny and Jenny’s situation. Johnny has one Change Key and Jenny has another.

We can add more locks to Johnny’s group. He may have his own bathroom, or a closet that all may be keyed the same as his bedroom door lock. Likewise, Jenny also has her own bathroom and maybe even a dance studio her brother is definitely not allowed anywhere near.

The possibilities are endless. Cleaning staff, maintenance, HVAC guys, pest control, babysitter, dog walker, Aunt Georgia. A hospital would have a quite a bit larger system than this family example. It is applicable to apartment buildings, office buildings, factories, horse farms, police and fire stations, restaurants, duplexes, schools, banks, you name it!

The first key creates what we call a shearline.