I know a little. I mean I have mainspring vises and can at least dismount them. It seems in the old days a gunsmith should have been able to make a lock from scratch. The whole kit and caboodle. I have a small box of orig. locks in various states of repair, all mixed up. How does one know how to make a tumbler work or when it is so far off to just give it up? Are there books, videos or classes on the subject? Jaeger