This is a 90 degree / right angle guide for a dewalt DWE6423 sander (the ones typically purchased at the big box store).

I had a festool ETS EC 150 and find type of jig incredibly handy for that so I decided to build one for the dewalt sander and leave it on at all times.

Screws together with an M5 screw and nut. I had some problems with the strength around the nut and it rotating but I just jammed a screwdriver and was able to tighten. If I planned to take this off, I would have printed with more walls or more infil to solve that problem.

I designed it in fusion360, I am a total hack when it comes to fusion, I've included the model, but if you have real experience with it, don't be surprised by the file and how I accomplished the model.