Today, I spent some time with our locksmith learning about keying the Disc Tumbler Cylinder Cam Locks, and I learned a lot. While they are such tiny locks, they require more time to rekey than a full-sized front door lock does. I found the process interesting and think you might too.
Keying a Disc Tumbler Cylinder Cam Lock
First, I learned that while the keys have a three-digit number on them (e.g. C413A), that isn’t the key number. It is a code you use in a book to find the real five-digit key number. After this, you have to find out if the lock is part of a master key system or not. If it is, then you need to know the five-digit master key number as well. When it comes time to choosing which disc numbers go in the cylinder, you have two options. Either double up the key numbers of the change key (the key which opens the lock), if not master keyed, or pair the change key number with the master key (the key used to open a group of locks) number.
Understanding the Numbers
So, if the change key number comes out as 40624 and it isn’t master keyed, you choose discs 44, 00, 66, 22, and 44. Let’s say the master key number is 20642, then the discs for that lock in this same scenario would be 42, 00, 66, 24, and 42.
Now we know what numbers we need, we can do the actual work. First, we pull out the keys and set them aside to potentially use for another job. Then, we remove the five discs from the cylinder without spilling the springs out (which I did on my first attempt, then had to use tweezers to put them all back in). Next, you add the new discs and pound them into place. We have a machine that makes keys for you. You have to use a few dials on it to set the cut position and the depth (key number numbers). Lastly, you have to test the lock with the new keys you just made.