Just IN- G78 Threading Problem

[bigmantate]

I am running 2 machines producing the same product but I cannot get the new machine to screw cut properly.

Thread size is 5/8" BSW.

Old machine is Fanuc series O-T and I am using the following G76 command: (THIS RUNS OK)

G76P030055Q55R.01
G76X12.92Z70.P1478Q80F2.31

TOOL START POSITION IS X20. WHEN THE FIRST CUT IS MADE THE TOOL MOVES TO X15.716 WHICH IS FINE.

ON THE NEWER MACHINE (SERIES 310i - MODEL A) I AM USING G78 COMMAND WITH EXACTLY THE SAME SETTINGS BUT WHEN FIRST CUT IS MADE THE TOOL MOVES TO X13.2016 WHICH IS FAR TOO DEEP AND THE INSERT BREAKS.

PLEASE HELP

THANKS

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