So use the minor diameter of the small end of the thread or the minor diameter of the large end?

I need to thread mill a 4"-8 NPT external thread on some pipe. What diameter do I need to use for the toolpath? Should it be the major diameter of 4.434" or 4.5" - the OD of the pipe? At 4.5" it looks like it would be to large. I have set the taper angle to 1.7833°, just not sure of the correct diameter to toolpath to get me close to size without putting a huge comp value in the control.

I need to thread mill a 4"-8 NPT external thread on some pipe. What diameter do I need to use for the toolpath? Should it be the major diameter of 4.434" or 4.5" - the OD of the pipe? At 4.5" it looks like it would be to large. I have set the taper angle to 1.7833°, just not sure of the correct diameter to toolpath to get me close to size without putting a huge comp value in the control.

I need to thread mill a 4"-8 NPT external thread. What diameter should I be using for the toolpath? Should it be the major diameter of 4.434" or 4.5" - the OD of the pipe? Done plenty of thread milling but not an external NPT yet. I have the taper angle set at 1.7833°, just not sure of the correct diameter to toolpath to get me real close without putting a huge comp value in the control.