OK, I understand.
Rubbings is a good idea, one that I had not thought of. I think this will reveal a lot about the work that can't be seen by the naked eye.
However, I have hewn timbers entirely with a narrow axe, I have hewn them with a big 12" American style broadaxe, I have hewn with a little Gransfors 1900, and I have hewn with a great big 14" German goosewing. All of these methods leave distinctly different finishes, and the one left by the 12" American pattern matches that found on local barn timbers.
The adzing of floor joists I have seen, as with the adzing of the ends of square ruled timbers. I know that the adze was used for cutting joints, though I have not observed this with my own eyes. But, I am very confident that an adze was never used to surface or finish a whole length of timber. That would be a painfully slow process! In my opinion, the slightly scalloped surface of some timbers that many associate with adzing is probably actually the result of finish hewing with a narrow axe, which leaves this same finish.
