I am creating an enclosure for an electric vehicle charger (OpenEVSE), and it is my first time using a Tormach. I am creating holes for a display, button, wire grommets, and circuit board mounting in a Hammond aluminum enclosure. It is between 2 and 4mm thick. For the larger areas I am cutting out, I was planning on buying a 0.25" 2 flute HSS uncoated square end mill from Enco. Then run it at 4000rpm, 16in/min feed rate. Does this sound reasonable?
Also there are some through holes I need to drill. They are for 4/40 aluminum fasteners. This ends up being I think right about 3mm diameter holes. It doesn't look like Enco or McMaster-Carr have metric Drill Mills. Any suggestions for doing these? Should I just get a 1/16" Drill Mill and then use a drill press with a 3mm bit to make the holes larger?
Thanks for any advice, I want to make sure I am ordering mills that make sense and my experience is lacking.
Dan