Peter Martin wrote:I'd like to get a grasp on the basics. Simple system development and understanding how to minimize "cross-keying" combinations (and which key pinning combinations MACS eliminates).
I'd prefer to learn to lay out an old "paper" generated system before just relying in a computer program to generate one for me.
Pete
The math is not hard, assuming you're not doing anything fancy like rotating constant, maison keying, etc. The important points are to decide at the outset how large the system will be (how many levels and how many change keys per master). Those parameters are hard to alter later, so always leave yourself extra room. Then decide which chambers to hold and which to progress. For the latter, progress the chamber by the step increment for the chosen system.
For example, a simple Schlage (2 step) system, one level, with 4 changes per master might look like:
Top master key (TMK): 11111
Change keys: 31111, 51111, 71111, 91111 (last one violates MACS though)
A two level system, 4 changes per master:
TMK: 11111
Master keys: 31111, 51111, 71111, 91111 (violates MACS)
Change keys under master 31111: 33111, 35111, 37111, 39111 (violates MACS)
You get the idea. The important points to remember is that the TMK has all cuts at the master level, change keys have 0 cuts at the master level, and everything in between determines what level the master key is at. There are lots of terms to describe those relationships. I like using TMK and change key because they are unambiguous no matter the size or complexity of the system. A master key may be a master, grand master, great grand master, great great grand master, etc. depending on the system size and where it fits in. For large systems I like row master, vertical group master (or column master), page master, grand page master, etc to describe keys that have 1, 2, 3, 4, etc. cuts on the TMK bitting. This goes back to manually laying out master systems in grids on paper.
Happy to answer any more specific questions if you have any.
