Back in the day, this was a “chart”:
The back sports an 1889 copyright date:
It’s a steel slab about 3/16 inch thick.
Perhaps the original owner, one “E Dunbeck”, scribed his name on the back. Perhaps he gave / sold it to Mad Phil, who passed it on to me. Although I may not use it much, it has a place of honor in the tool cabinet…
You could get a new 185 Time Saver direct from Starrett, with the front and back sides reversed: same holes, mostly the same printing, just flipped.
Verily, they don’t make ’em like they used to!