Artificer, you can do it all with files, a brace and bit, and brick dust to polish. Or you can do it precisely using a lathe, mill, drill press, and automotive sand paper, or a combination thereof. However, the latter would not be period correct, now would it? Of course, cast parts would not pass either would they? Anyhow, the metals they have chosen to use, and the heat treat info they give, are not the best for the requirements at hand. At least in how they are to be used and heat treated. Research your heat treat for these metals before doing it by their recomendations. Although, what they recommend may work, it might become a question of, how well, and for how long. I would strongly suggest you get in contact with Jim Kibler before any heat treat of their parts. He would be able to tell you the best way to go with that. If you do not have a heat treat oven, I can do it for you, to Jim Kiblers specs, as long as I have the necessary quench oil, and I believe I do. A sort of truce offering, unless Kibler agrees with their recommended methods, and as he is a metallurgist, I doubt that.