[Sideband]

No don't chance a Q-Max type hole punch. They are excellent for soft metal but die-cast is hard and brittle. I tried it in my early days when I wanted to build a pre-selector for my shortwave radio when I was around 17. I needed a 3/4 hole for the slow-motion drive and drilled a pilot in the lid of the die-cast box (which would become the front), inserted the Q-Max and began to turn the screw barrel down....it started to cut and then there was a bang and a large chunk of the die-cast broke out...I had to wait another week to go to Home Radio and buy another.... I think a cone cutter or maybe one of those hole cutters you can fit to a drill will work. Failing that, a circle of smaller holes and then punch out the centre, finishing off with a rotary file