Thread cutting using 4th mill axis

Hi, I am trying to workout how to cut an external thread on my stepper driven milling machine using the 4th axis for rotation "A" and the "X" axis for the pitch of the thread with the cutter in the milling machine spindle.
All I can find in the help files is for lathes.

Steve

g20
g0 x0 z0.25 a0
g1 z0.23 f10
g1 x1.0 a720 f100

Will cut a 1" long "thread" with a pitch of 0.5" on a 0.5 diam bar with a thread depth of 0.02" using a "V" point cutter
ie the a axis will rotate twice as the X moves 1 inch

Note the not very real example

Doing it with a rotary axis on a mill doesn't use spindle synchronised motion like a lathe.

This sort of what you are looking for?

try googling for "thread milling" and you may find you don't even need the 4th axis.
Roger

Thanks for your help that should work.
Steve