[MichaelGolden]

I don't know know how to calculate it but I think I can tell you where to find it., EMC and Mach were created from the open source NIST program. As I recall they downloaded the G code source code and then developed the GUI and software from there to run it. If you code on the EMC forum someone may be nice enough to cut and paste that section for you. Although I have not found them particularly helpful on some matters. Your success may be different that mine. Alternatively, I believe a copy of the G code engine can be found with some searching..
Dan Mauch

I don't think motion control software will have the answer for me. Because the f word in mach or any control software simply interprets the F word as completed time = 1 / the f number.

What I need to know is how the f word is calculated by the post processor from the 3d distance from move a - b, pulled from a cartesian coordinate system. Which is easy with 3 axis but not sure how the rotary motion is integrated.

So I'm going to have the choose the longest distance between rotary and linear moves to determine the fword. Because sometimes cut moves are purely rotary motion with little to no xyz motion.
-The rotary distance along parimeter using radius from zero point. Or the 3d distance of xyz. Unless any mathematicians know a better way to do it.

Does anyone see an issue with this?