There is no speed encoder on the star mill so unless one has been fitted it’s no

I’m also sceptical that mach3 can do this as I could never get mach3 to cut a thread on a lathe. The problem is mach3 only takes a single pulse per rev from the spindle which is simply not good enough to sync the z and the spindle for tapping
You could use a tapping head but I thing you will struggle with z travel

Fit an encoder disc and optical sensor then dump mach3 and replace with linuxcnc. That will certainly do rigid taping

Paul


Sent from my iPhone using Tapatalk