I made this to be able to drill holes in the enter of 3030 extrusion a little easier. I should slide in to T slot pretty easy. I needs supports that are a pain in the ass, but check out the pic of how I put them in 3MF file will have them. I use Prusa Slicer. Enjoy.
youtube.com/ChrisRiley
And a bonus picture of Hank peaking at me while I work.
The author hasn't provided the model origin yet.