A very simplistic sanding drum for your drill or electric screwdriver.
It has a standard hexagonal screwdriver bit attachment piece and a 1mm slot to fix sanding paper.

This thing is cut at the top at 5 degree angle in order to prevent delamination across layer lines while in use

I've printed mine without supports because I don't really care about inner part finish. In PLA it should bridge just fine

UPD: Added version two, where the shaft is separated and will be printed horizontally to help structural integrity.
Since lowering infill percentage won't speed up printing much, I'd recommend to print this at 100%