extrusion/tube corner connector

thingiverse

Connect identical square tubes or aluminum extrusions and join them together to form a box shape corner. This design is quite versatile. It might take several trials to get the hole size just right without being too loose. The good news is that you can adjust that hole size without altering the outer dimensions, so the parts will still all match up perfectly. <b>SLICING NOTE:</b> I noticed that Cura would attempt to bridge the length of one shaft and the width of the other, so when I slice the part, I turn it 45 degrees to the side. This may not be crucial if you actually print with support material though.