This is my Handel design for Countersinks it is easy to use and has a good strength holding everything with a 10mm shaft (added 1/4" shaft).
I printed the Mainbody and Tightener-screw with 90% and the shell with 100% infill.
All parts are printed with a layer height of 0,15.
Maybe you will need a brim for the Mainbody.
I chose PET-G Filament becouse of the good layer adhesion.