Stub acme external 1 1/4-4 threads with double lead

[Howard Jones]

Hello. Can anyone show me a G76 program to accomplish making the above mentioned threads on a Doosan lathe with fanuc controls. The threads are approx 1.5 inches long. My brain is smoking on this one. Would greatly appreciate help.

 

[MaCon]

I would G76 (my first lead) with F as Thread Pitch x2.

Then add (Thread Pitch x1) to my G00/pre-G76 Z start position
(establishing a new G00/pre-G76 Z start position for the second lead).

Then G76 (my second lead) with F as Thread Pitch x2.