About this 3D model

My friend needed a compact way to square of the rails on his RailCore 3D printer, so I designed a 15mm x 15mm square that screws to a 1515 Aluminum Extrusion. I printed two small guides that ride in the center slot and have notches to allow for a standard metric nut. The square is held tight by a M3 screw. I am uploading a variation without guides in case you have an extrusion with a different slot width.