I built a couple of Siler kits with just the drill press follwing the instructions in the Siler kits. The problem with this method is that the axels on the cast tumblers can be out of round as cast, filing them in the drill press just makes this worse, you really need to use a lathe, or, if your making the tumbler from a blank, a tumbler mill, to keep things concentric at this stage. I know lot's of kits have been built with nothing but a drill press, but it isn't ideal, if you want a world class lock than you need to start things off right. These days a lathe is a relatively small investment and the things you can do with it will add a level of versatility to your gunshop not matched by many other tools.
Alex
I can agree to that.