4040 Open build profiles right angle joint - what's the best way?

I would like to connect 2 aluminium extrusions at the right angle end to end. What is the best way to have nice square joint, stiff and easy do?

I am thinking about something like on the picture below (using 4 bolts per corner), but I am worried that as a tight the bolts the profile will deform and that connection will not be stiff enough. Putting tubular spaces inside the profile sounds like a bit too much hassle. Is the triangular corner bracket really the only choice? Would 4 bolts link on each corner be enough to hold my y assembly together?

Button head cap screw and washer, drill a tool access hole for each screw 20 mm from the end of the frame piece.

Edited 1 time(s). Last edit at 12/19/2018 04:17PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks, nice clean and relatively easy to do. With this solution 4 bolts per corner should keep everything square ant rigid. I hope that extrusion supplier will cut the profiles at the right angle...