I'm building a table a small workbench out of some 3/8in aluminum extrusions I got from work. Instead of buying some corner brackets, I figured I'd design and print them. They're on the Ultimaker right now so I'll take some pictures of the finished product when they're completed. They do take some time to print depending on the infill percentage but I'm in no rush. When completed they will be fastened to the extrusions with some 1/4-20 thru bolts. Pictures will be online soon!
The openings where the aluminum extrusions will be fitted are 8.45mm and the overall height is 118.5mm. The slots are 7.62mm by 17.88mm. This part can easily be scaled in your slicing software. Let me know your thoughts, thanks.
Post-printing I will either wipe the sides with acetone or put the parts in a acetone vapor bath to smooth them and give them a nice shine.
Measured the rails with dial calipers to get some basic dimensions and used Autodesk Inventor to make a model.