Just wanted to comment on the general condition of the fuller and the mushrooming in particular.
I'm not a black smith, and haven't met very many of them, but the few I have encountered and observed would never be caught dead with any working tool in that condition.
And, as a self taught mechanic/fabricator/tool collector, I myself would never be caught dead with a tool in that condition. I don't own any fullers, but I do have a sizable number of hammers, mallets, and other striking tools, and the first thing I do when I acquire a heavily used tool is remove the mushrooming. Then I dress the striking surface, and finally, dress the cutting/forming edge. I need both my eyes everyday, all day, and for the rest of my life.
I'm pretty sure whoever owned that fuller was not a black smith or farrier. More than likely, the owner of that fuller was a hack and probably misused the fuller for everything except what it was intended for. JMHO.
Your thoughts?