Mechanical question

[rsocor01]

I might be wrong, but I don't think you can "punch" holes in a plastic enclosure. Like Dave said you can pay somebody to make the holes for you or you can buy your own CNC machine. There are a few members of this forum that might be able to guide you in the right direction in case you decide to get your own CNC machine.

Robert

[keithdoxey]

I made a jig for cutting connector holes in plastic panels and boxes. Mine werent for DB9 connectors they were for SCART AV Connectors which are basically rectangular but with one end at an angle.

I made the jig from MDF and made it larger than the hole required then using a router with a follow collar just ran it round the inside of the template.

[dhouston]

or you can buy your own CNC machine.

Even a small, bench type milling machine with digital scales/readouts would be fine for low volume. There are some with retrofittable CNC controls as well as numerous DIY projects to add CNC to small milling machines and lathes.