Understanding Master Key System Terminology Before You Build One
A keying hierarchy uses a layered vocabulary that can feel opaque until someone walks you through it. At the base level sits the Change Key — sometimes called the servant key — which opens only a single lock or a small group of identically keyed locks. Above it is the Master Key, which opens every lock within a defined group. Many Chesapeake businesses need a third tier: the Grand Master Key, which opens multiple groups simultaneously, useful when a facilities director needs unrestricted access while individual department heads hold master keys for their own wings. At the top of large systems sits the Great Grand Master Key, reserved for ownership or executive-level principals who need complete building access without carrying a ring of forty keys. Our technicians will map out which tier each role in your organization genuinely needs — over-issuing access is a security risk just as real as under-issuing it.
Two additional terms matter when we talk about the physical locks themselves. A mortise lock is a rectangular cartridge set into a pocket routed into the door's edge, as opposed to a cylindrical lock that passes through a bored hole. Mortise lock cylinders are the workhorse of commercial keying hierarchies because they accept interchangeable plugs that can be pinned to virtually any key combination in a large master key system. Door knob lock hardware, by contrast, typically uses a smaller cylindrical format that limits the number of usable key cuts and therefore the depth of hierarchy you can practically achieve. Knowing which format already exists on your doors — or which format makes sense for new installations — shapes the entire system design from the start.

