Although mine were all nicely packed into the back of the machine by the maker a basic metal electrical enclosure like these should do. make sure all holes are protected with glands etc.

I've made 3 for my lathe, mill and power feed. All use the same basic approach: baseplate with two sides attached and possible one or two ends.

The lathe electronics sits on a well protected shelf under a bench so doesn't have endplates or top. Bottom and sides are 3mm ali, rails of 12mm angle along the long edges of the base to attach side plates. All held rtogether with pop rivets.

Mill is similar but as it is screwed onto the end plate of the mill enclosure the elctronics is fully enclosed. Same construction method though, with a folded 2 mm aluminium lid held on with screws.

Power feed box is glued up from 8mm scrap Valchromat sheet (Gorilla Glue Clear). Plenty of room for Arduino with CNC shield carrying driver, PSU, Bluetooth module, and choc block to connect stepper.

Auminium end plate with IEC mains inlet (fused with switch). Lid is 1 mm ali sheet with a single fold at the other end.