Don't know what the last couple of posts are getting at, but to go back to post #12. A 12-grain is a pretty fine rasp, and leaves a very fine tooth pattern, though it does depend a bit how you use it, of course. While you can go even finer, so far I've found that to be as fine as I need in rasps, though I quite often follow up the finest rasp with a file. New, sharp files do a very good job on hard woods, and the long teeth leave a very clean surface (just like a float, only much finer).
Depending on the job, I use rasps & files in preference to spokeshaves because they aren't as sensitive to changes in grain direction and get into tighter curves. I prefer to go as far as I can with the rasps or files because it's easier to keep surfaces flat, if I move to scrapers or sandpaper too soon, they tend to exaggerate any dips in soft spots more readily than rasps.
You would indeed need the right punch, & need to resharpen it several times to do one rasp, I believe. You would also need to practise long & hard to get the accuracy that raises virtually identical teeth at just the right angle & pointing in the same direction, every time! It's one job I don't think I will ever tackle, but there's no reason why someone with enough time & determination & the necessary forging gear couldn't do it, otherwise.
Cheers,