30x30 alu profile brackets

This is set of simple brackets to join 30x30mm aluminium extrusion profiles with 8mm slot (i bought mine on http://ehlinik.cz).
Except corner bracket all printable without supports. Print corner bracket in orientation provided in stl for better strenght.
You will need M6x12 (or M6x14 with washer) screws and low-profile M6 nuts (DIN439).
For adjustable feet use M10 screw and nut. You have to add pause to gcode at height 9mm and insert nut inside. Above the nut is one solid layer for easier pri