Waltham 1873-6"M" grade C and grade "special" per the grey book. Anyone able to shed some light in the grade special? Pocketwatchdatabase shows grade C and variation as w.m. Ellery quality, although I don't see anything in the grey book that relates to either? As I understand wm Ellery, it was a label they put on early mass produced lower quality watches. It was also used as a grading on higher quality watches, 1873-6 was there highest grade 6s at the time so I assume the latter is correct? I assume there are other letter grades other than c as well. Any info would be appreciated.
Most visitors online was 1990 , on 7 Feb 2022