Monro,
On Jim Turpin video about building a longrifle, not sure if it was his Jim Chambers build or another, he uses a auto body sanding tool with course sandpaper that is about 18” long to smooth his forearm after he roughs it in with rasps, files, etc. they carry the auto body tool at Harbor Freight or at least that is where I got mine. It helps clean up and smooth the sides. Good luck!
elkhorne