Yes, you can do it and it's not too complicated.
You'll want to climbmill from the inside out, so the chuck will be rotating clockwise in the positive-C direction.
Here's an example... let's assume
- You're cutting a 1.00" x 12 tpi internal thread, 1.00" deep.
- You're threadmilling 1018 steel at 400SFM with a 0.5" diameter, 4-flute threadmill.
- You're feeding at 0.003" per tooth, which is 36.0 IPM or 4127 degrees per minute for the C-axis (11.46 RPM) at the 1.0" major diameter
- Your part face is at Z0
- You probed your threadmill and adjusted the offset such that the center of the tool aligns with the center of the spindle at X0.
M45 (engage C-axis)
G97 S3000 M13 (start spindle at 3000rpm)
G0 G54 X0 Z.25 C0
G98 G01 Z-1. F10.
X0.5 (this will take the threadmill to the 1.0 major diameter)
Z0 C4320. F4127. (feed Z-axis a distance 1", 12 revolutions of the chuck, 36 inches per minute)
That should be it. Definitely do a dry-run first. Threadmills are expensive, and Mori Seiki NL lathes are even more expensive.