ruffrecords said:
How about trying it with a Dremel - they have high rpm and routing bits are available.
I was thinking of buying one back in the day.. a multi-tool like Dremel would indeed be ok for a router that size, whereas a power tool is likely too large and could damage it as it has more torque (ultimately it'd be nice to cut aluminium but I was thinking of making a large one for loudspeaker building out of plywood so it needs a working area of 1220x2440mm, I drew plans for a 500x800mm for a start as a compact woodworking router is ~200mm high on an average)
They're probably ok for PCBs and stuff too.
It's almost 15 years since I last did milling with a chisel drill (now I remember the trick is to mill at an angle towards the workpiece when doing slots which requires a slightly longer bit but the risk of breaking it is smaller)
The bit in my case would need additional horizontal support too, those Dremel bits are kind of short I guess but I could make the guide rail (=gantry in CNC slang) wider.
Sorry for the off-topic.. but I've done a cutout for a USB-A port in one of my builds (Arduino Uno-based) and it called for very precise work too although it had no screws/bolts like yours has, the PCB provided the support.
EDIT : here's a more recent pic :
There are screws and pieces of wood that limit the x/y axis movement so the gantry doesn't fall/come off and to prevent milling the rail by accident which reduced the work area to 125x85mm (somewhat poor engineering on my part but I kind of saw that coming, I guess it's still useable up to 3RU)