Hi everyone.

OK, I have been programming fanuc lathes since 1988. Using the 2 line G76 for threads. I have just started with a new company and the control I'm using is a 30i on a CMZ 2 axis lathe .

I tried programming a 16mm x 2 ext thread. But no matter what I did the first pass was at 13.7 mm. Very deep and not good. I tried starting at 24mm, 30mm etc. Still drops straight to 13.7 mm for the first cut. How does the system decide where the 1st cut begins?

G0X20.0 Z5.0
G76 P020060 Q010 R0.05
G76 X13.400 Z-50.0 P1228 Q307 F2.0

I have used the manual guide and that's OK, but why??

Cheers all

Pete