CNC mill would be perfect. My drill press has a laser center guide but I still had to eyeball it to get it perfect. I think the vise holding the box wasn't tight enough. I didn't want to crush the box so I didn't tighten it too much and it might have moved a bit on the initial bite when the drill came down.
I'm pretty happy with how it turned out though. The ground soldered to the brass nut makes the ohm reading accurate and more solid than a screw tapped into the case. I might do the same with the other boxes.
I'm pretty happy with how it turned out though. The ground soldered to the brass nut makes the ohm reading accurate and more solid than a screw tapped into the case. I might do the same with the other boxes.