Yep, using the half nuts for threading.
The gear configuration is as follows:
Top stud gear - 40t (according to my parts manual it should be 20t)
Idler gear - 80t
Stud gear to lead screw - 40t (this is correct as it's indicated on the gearbox thread chart)
Lead screw - 9p
Another issue with this machine is that the longitudinal power feed spins way too fast, not delivering a good finish.
Wondering if the top stud gear could be the culprit for both problems?