This is a box I designed as small as possible for an inline switch using a common switch. It uses 4-40 socket head bolts cut down to fit.

Print instructions

I printed it using ABS but PLA should be fine.
My ABS settings where...
Layer height, 0.2mm
Nozzle, 255
Bed, 100
Layer added that is drilled out later in order to avoid using supports.
8mm Brim
One piece printed at a time.