For a small musical instrument I need a thin sheet of spruce (1.5mm). Normally I’d just buy a guitar or lute top, but for this one I need the highest quality I can get, with very narrow rings. So my idea is to saw down a blank for a violin top (25mm at its thickest point). I need to do this with as little waste as possible, because a good spruce top can cost 100-300€.
Is there a way I can do this with hand tools?
I think you could do this with a pull cut plane after you cut to close to the correct thickness with a hand saw. A pull cut plane will prevent the thin sheet from buckling as you try to thickness it, just have to get clever about anchoring it. You could glue a board to the back and then hook it on a table using that board, plane it until you’re satisfied, then cut the board off.