Ron,
There is no operator's manual specifically on the 101.07403. You should acquire a copy of the Clausing "Manual of Lathe Operations". I would suggest you look for one dated 1957 or earlier as the next edition after that only shows photos of the later 12" (Commercial) and the 6". They turn up on eBay fairly frequently. 1955 seems to be common. As Pierre said, Clausing still carries some parts for your model. And eBay is a potential source.
The Downloads section on this site has a copy of the illustrated parts manual on the 101.07403 (and the next two models -just ognore the QCGB page). However, you won't see the Downloads tab until you have a few more posts. If you'll send me your email address today or tomorrow, I'll send you the PDF.
Robert D.