Lesson 6: Master Key Systems - Part 3

Building a Master Key System

You construct a master key system by creating multiple sheer lines through the use of master pins. The multiple sheer lines enable different keys to engage with the same cylinder. To construct a master key system you need to compare the code of your keys, and split the difference with your master pins.

The Essentials

      1. Compare the key codes you plan on using. It helps if you write them out, one above the other.
      2. Select the lowest numbers from each cut. For example, if your two codes are 22543 and 25243, you would select the 22243. This code will be the bottom pins when you rekey the cylinder.
      3. The difference between the two codes are the master pins you will select. Write this number below the code for bottom pins. If there is no difference, write an x to represent that there will be no master pin for that cut. Continuing our example, the master pins would be x33xx.
Master Key 22543
Proper Key 25243
Bottom pins 22243
Master Pins x33xx

It is important to remember that a master key system should be designed in such a way that prevents unintentional cross keying.

Any combination that results in a master pin smaller than #2 can not be used. These combinations can not be master keyed and should be redesigned before you continue. Once the master key system has been developed, it is time to pin the cylinders to the master key code. This process is similar to rekeying a lock, with a few distinctions.

Series Navigation<< 06 Part 2 – What is a Master Key?06 Part 4 – Master Keying the Cylinder >>