Still creeping toward a possible solution. Tapping with a hardened punch did nothing but smoosh it down from jagged to smooth. The suggestion from a sewing machine restorer is to use a drill press to either drill out the broken guide or make a new hole just a little above it. This involves getting a heavy drill press buried in the garage onto a stand I don't currently have, cleaning, oiling, learning. A machinist, I am not -- but I'm willing to try, fully cognizant of the fact that I could ruin her. It's not a beauty contest, believe me; this machine was dug out of a garden, completely frozen and with a plant growing out of the missing faceplate. Initially she was only supposed to be a practice/learning machine, but you know how you get attached and emotionally involved...