Master Keying David M. Koenig, CPP Master Keying Is... System Of Organizing Numbers – For Cutting Keys – For Pinning Locks Grouping Of Locks And Keys Set Of Locks That Are Operated By More Than One Key Master Keying Provides Convenience Over Security Separate Keys For Individual Locks Keys To Operate Groups Of Locks Single Key For All Locks In System Ability To Carry Fewer Keys Organization Of And Management OF Lock & Key System Master Keying Disadvantages Makes Locks Easier To Pick Small Master Pins Increase Service Issues Higher Re-keying Cost If GMK Or GGMK Keys Are Lost More Thought Involved In Administration Controlled Destruction of Lock Security Master Keying Terms KA - Keyed Alike - Several Locks Operated By The Same Key KD - Keyed Different - Each Lock Operated By It’s Own Key Master Keying Terms CK - Change Key – Work Individual Lock MK - Master Key GMK - Grand Master Key – Works Large Group Of Locks GGMK - Great Grand Master Key – Fits All Locks In System Master Keying Terms SKD - Single Keyed Different – Lock Set To Change Key Only NMK - Not Master Keyed – Similar To SKD Levels - Number Of Different Types Of Keys In System – Example CK-MK-GMK = 3 Level System Master Keying Terms 1 Sectional Keyways - Variety Of Key Blank Grove Sizes And Shapes – Divided Into Groups – Some Patterns Are Wider Than Others – Higher Level Patterns Fit Into Multiple Keyways – Allows Cut Numbers To Be Repeated System Size and Security 5 Or 6 Pin Chambers (more is better) Chamber Depths Pinning Increment (Key / Pin Wear) How Many Chambers Are Progressed Angles (Or Other Factor) Employed System Size and Security MACS (Maximum Adjacent Cuts) Loss How Many Masters Employed Sectional Keyways Typical System Example 8 Depths (1-10 Less Two for MK) Less Increments of Two Used In 6 Chambers Equals… 4 To 6th Power Equals… 4,096 Theoretical Combinations Less MACS Of 20% Equals 3,276 Maximum Combinations Medeco Biaxial System Size 4 Depths (1-5 Less One Number For GMK) Used In 6 Chambers Equals… 4 To 6th Power Equals… 4,096 Theoretical Times 9 Sections (Angles) Equals... Medeco Biaxial System Size Equals 36,864 Changes Under Single MK With MACS Loss Of 20% Combinations (Maximum Adjacent Cuts) Over 29,400 Maximum Combinations Number Of Chambers Used For Master Keys Reduces Maximum And Determines Availability Within A MK