If you have ever wondered, what is master re-keying, the answer is fairly simple.
When you have several locks that all work with different keys, it is necessary to keep a key for each individual lock.
Perhaps you don't want to carry around that many keys, and desire to have just one master key that will open every lock.
In this case, it is possible to have your locksmith adjust all the locks so that one key will operate every lock.
He will reset the pin and tumbler system within each lock so that they are the same.
This is known as Key-A-Like, and it is slightly different than master re-keying the locks.
Yes, you have one key that works all the locks, but all the locks have the same inner mechanism, and someone can take their key and then operate all the locks.
This may not be desirable, for example, if you want to keep your office private, or there is a cash storage room with the same lock.
In this case, ask the locksmith for master re-keying.
With master re-keying, the locksmith will give you one key that can operate all the locks, but each lock will have a different inner setting for the pin and tumbler systems.
There will be different keys for each lock, as each can have its own setting.
Your one master key will be able to operate all locks, including your own lock.
So, you end up with two keys, one that will work only your lock, and one that will work all the locks.
You end up with fewer keys than when each lock required its own different key.
The major difference is that with master re-keying, your locksmith can reset the locks so that one single key will control all the locks, but each lock can still work independently with its own special key.
This helps you allow certain people access to some areas but not others.
This also is good for giving maintenance people just one key for several locks instead of entrusting them with multiple keys for multiple locks.