Joe,
I can't help with your question but just thought I'd pop in with this info:
While attending a local historical re-enactment, I noted someone sewing a period clothing item on a treadle machine. They we sitting outside, in the shade of an old oak tree - very picturesque!
Anyway, I noted their machine 'belt' was actually braided string. I asked them about this and their reply was with all the shows they attend their belts were getting jostled around and broken in moving site to site. They used something like the old style store string, tripled up (three strands each for a total of 9 strings) and then they lightly coated the string with beeswax.
Just an FYI.......
Shari