Miller "Key Changes"

[mercury]

I don't understand that. Looking at the key there are 6 unique positions (assuming the entrance slot acts as warding so the key can not be used up side down) and for each of those positions 6 possible depths of cut for a total key space of 36 possible keys.

Consider a key for a lock with just two levers, with 6 possible cut depths.

For each of the 6 possible cuts for the first position, there are 6 possible cuts for the second position. This gives 6x6=36 differs which could be represented as follows :

1,1 1,2 1,3 1,4 1,5 1,6
2,1 2,2 2,3 2,4 2,5 2,6
3,1 3,2 3,3 3,4 3,5 3,6
4,1 4,2 4,3 4,4 4,5 4,6
5,1 5,2 5,3 5,4 5,5 5,6
6,1 6,2 6,3 6,4 6,5 6,6

For a key with three levers, 6 possible depths, we can take the 36 possible two lever keys and multiply by 6 for each possible cut for lever 3. Therefore there are 6x6x6=216 possible keys.

The same logic gives us 6x6x6x6=1296 possible keys for a 4 lever lock, 6x6x6x6x6 for a 5 lever lock and 6x6x6x6x6x6 for a 6 lever lock.

As BBE explained, not all of these theoretical differs will be used for various reasons.

I hope that clarified this and not made it more confusing instead!


...Mark

[BBE]

As I see it, a 6 lever lock with 6 possible notch locations on a lever would mean 6x6x6x6x6x6=46,656 differs, assuming there are no other restrictions upon the key space.

...Mark

Well, I don't know what I was thinking before, you are absolutely right. The full potential for the 6 lever lock is 46,656. The actual changes will be somewhat less, probably around 20% because the key can be reversed and you wouldn't want 6 1's, or 2's, etc.
BBE.

[BBE]

note to BBE: perhaps this should be added to the LIST Council Locksmith Dictionary?

Thanks for noticing Pete. Many years ago it was in there, looks like some cut and paste may have gotten rid of it. I'll see if I have a printed version from the 80's, if not I have started the process to add it.
BBE