Masterkeying

[Rockford]

I've read through a number of posts on Masterkeying, and just finished reading the Matt Blaze document on the subject, but cannot find a definitive "easy" answer to the following - without following Matt's "attack" suggestions towards the end of the document.

If I came across a masterkeyed system, installed by another Lockie, and the customer wanted additional locks adding to the system - how would I go about. Assume I've access to the Master Key, and each of the current "servant" keys.

Is there an easy answer, or will it involve deciphering the keys ?.

Thanks
Rockford.....

[_Ethereal_]

It can depend on how many aditional locks placed in the system, if a small number you could key it alike with one of the groups of locks - eg. group A MK A or something similar.

But if your adding alot of additional locks you could branch it out and create a new group that run on a different master key but all with the same TMK or GMK..make sence?

[MrB]

When you want to work on a master keyed system, you should have access to the system design. That would make clear the bitting of the top master key, and show how all the sub-master zones are organized.

Trying to reverse engineer a master key system without the original design paperwork would be cumbersome. If you had access to all the keys in the system you could read their bittings and then figure out the design, but it would not be quick (unless it was only a small system).

[raimundo]

As someone suggested, you might simply use a varient keyway, which could necessitate that you re cut the master key with a master blank (thinner, and designed to go into several key ways, like the schlage J or L might go into their C and E keyways. Another possiblity would be to go to six pins from five or vise versa.

[Rockford]

Thanks everyone for your comments and thoughts. Certainly a lot to consider - I just want to be prepared for when I'm faced with this situation.

I'm going to try and obtain a few of the books mentioned in the various threads I've read.

Rockford.....