this is a tool I designed for work where we will be putting headers on a few hundred feather boards. This jig helps hold the headers steady while soldering. My first design, seen in the photos, works, but not as intended. I redesigned it to use spring retention instead of just a drop in fit, and also expanded the relief for the LIPO connector. As of this time I have not reprinted and tested the redesign as i don't have my own printer to use. Hope you get some use out of this.
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/aIRUo3yduRM