A print friendly corner connection for Makerbeam 10mmx10mm, the countersink keeps the nuts and screw ends protected, nevertheless it looks better :), ...right? Thanks for your feedback
Orient the part so the closed counter-sinks side is facing the build-platform, and to achieve good counter-sinks quality, please don't forget to tick the print support structure box in cura.
Normal print quality takes longer, but it assures having a perfectly square Makerbeam structure, and not wobbly as using the custom L-shape corners (Makerbeam users will relate)