This is a 1mm mill. I am going to break it.
I am surely going to break it.
Amazingly I didn't break it. And the slot is pretty square.
This is a similar slot for an Ethernet connection.
The panel with the finished slots.
Now just drill the eight big holes.
And the forty two small ones. I really like the flat-bottomed drills. They produce essentially no burr when breaking through, and these little disks can be removed with a fingernail.
It's a match.
With the PCB fitted.
Turns out I misread the data sheet and while the Ethernet connection can be made the panel isn't flush against the various PCB connectors.
I misread the data sheet again and the connector still didn't fit properly. I resorted to a file, and now the thing looks almost like a product customers might pay money for.