You just paid for it, thank you very much!
I did omit to include the insert repair instructions and the South Bend
Bulletins for refitting the handle/dial backlash with the test screws I sent out.
I didn't have them completed yet, but they are posted to the website
for viewing now.
The old South Bend blueprints for the screw and nut called out .003 to .005
as the spec for backlash. The repairs that have been completed are falling in that range.
I had this material roll threaded in C1144 stress proof which as you might have found is
a very good match in appearance to the original screw, which was probably 12L14 or something
close to that, the 1144 will machine very well and still give good service life.
Take a few pictures of the repair if you can, I'd like to see them.