Project Box (70x50mm PCB)

Simple project box for housing a 70 mm x 50 mm x 20 mm prototype PCB. Insert knurled M3 screw nuts in the box top and secure using M3 screws from the bottom. External screw holes are wide enough for drywall screws.
Note: The 70x50 mm FR1 PCBs have very sloppy tolerances with respect to mounting holes, I usually enlarge the holes to 4mm that aligns 90% of the PCBs with the holes in the box.