I'm sure I wasn't the first, But I did come up with the idea independently-I needed to carve a perfetly straight, tapered, convex, chunk of birds eye maple, for the finger board of a upright tub bass.
I tapered it on the tablesaw, knocked off the excess wood on the front corners with a power plane, then I cut a 80 grit and a 120 grit 21 inch sanding belt, and using spray adhesive, glued them to a 3X3X3/8 aluminum angle "iron"
I then scribed the upper and lower arcs on the ends of the blank, and scribbled all over the face to be carved with a carpenter's pencil.
I clampd the angle "iron to a bench, and just scrubbed the blank back and forth on the sand paper, scribbling on the high spots now and then, until I had a finger board. And it looked great!
I don't know if it's accurate or not, because I've not finished the bass yet.I was 75% done with the project, when I moved to Texas, and I am not even sure where all the parts are at this very moment.
But the sanding apparatus performed superbly!