20mm Extrusion uses ONLY M3 hardware, screws and nuts

I was upset to not find extrusion that was easy to piece together and needed special nuts to attach parts. Then I would find out the screw holes were for M4 or M5 screws, so I designed this.

20mm, slots are designed to hold a 5.5mm M3 nut, and then screw down with M3 screws. Also the ends have holes in them to secure 20mm corner pieces with M3 screws.

I will be uploading more sizes, and yes this only has slots on 2 sides, 4 sides printed along the x-axis, the 2 vertical sides would droop