If you have a lathe, you have a drum sander. This was my first sander. I turned a hunk of 4x4 round and added a drum belt. A piece of melamine sitting on the ways with another hunk of melamine hinged to it for an adjustable sanding surface. I did tops, sides, and backs for two guitars on that setup.
Since then I found a used 16 in. Delta with a big bunch of new belts at a very good price. I bought it from a pro woodworker who replaced it with one big enough to do a door in a single pass. Now that's some serious drum sanding.