Still looking for a definitive statement, but according to some chatter on one of the other popular discussion groups way back a few years, some of the older Seneca Falls "Star" lathes used a 9 TPI lead screw. Had something to do with a 4/3 reduction gear setup in the headstock if remember correctly.
If so, might be a worthwhile lead (ha ha) to track down and maybe get a positive ID on the machine.
-frank