I am also looking for advise on educational books to purchase, any advise on what might be a worthwhile purchase to further my skills.

I have a Safeguard SD105 Safe in my shop with a S&G mechanical combo, as well it has a key cyl to the left of the dial. Because I am fairly new in the safe business and still learning, although my locksmith business has been in operation since 1990. I am looking for any advise my fellow locksmiths can offer me. This safe is mine which I received from a friend with no combination.