Warp wrote:
> andrel <a_l### [at] hotmailcom> wrote:
>> I personally think doing it in hardware with nuts and bolts is more 
>> impressive, but that may be just me.
> 
>   I suppose it's simply a question of cleverly allocating combinations
> of pin assignments to locks and keys. I can imagine at least one simple
> way of achieving a hierarchy of master keys with pin locks:
> 
>   In all locks, all pins have a cut for the highest-order master key,
> as well as the secondary cut for the lock-specific key.
> 
>   The locks are divided into groups of locks (eg. on a per department
> basis). All the locks in one group have the exact same secondary cut
> for the first pin, but this secondary cut is different in different groups.
> This way a master key for a specific group of locks uses the group-specific
> setting for the first pin, and for the rest of the pins it uses the setting
> for the highest-order master key. This way it can open all the locks in its
> own group, but it can't open the locks of the other groups (the first pin
> being different stops it).
> 
>   (If there are too many groups, using just one pin to differentiate between
> them might not be enough, but in that case more pins can be used for this
> purpose. The amount of combinations increases exponentially.)
> 
>   If each group should be further divided into smaller sub-groups, the
> same technique can be used with the second pin, the third pin, etc.
> 
>   Then there's the reverse problem: All keys, including lock-specific ones,
> should open a common lock (eg. the door leading to the entire department).
> A lock-specific key should open, naturally, its own lock *and* the common
> lock, but it nevertheless must not be a master key which could be used to
> open your work pal's office. Obviously master keys should also open these
> common locks as well. However, the lock should not be openable by a key
> not related to the company at all.
> 
>   In other words, the situation is kind of a reversal: The common lock is
> a "master lock": It should be openable by a group of keys, but not by any
> keys outside that group.
> 
>   I have difficult time bending my mind into resolving how exactly it is
> done, but I can perfectly imagine there's a simple way. Ingenuous, but simple.
> 
Our keys are more or less saw shaped, if you know what I mean. The 
master keys have this extra groove. It also has bigger indentations on 
some points. Put another way, if you have 3 or more keys that have the 
same master, all you need is a mechanical workshop to make a master. But 
don't tell anyone, I am not supposed to know.

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