Fourperf--
Thread milling is simply a three axes helical motion. Here is a sample thread milling prg that does threading on a boss:
%
N1O4326(SAMPLE THREAD HOB ON A BOSS
N2M6T1
N3G0G90G80G17G40S5000M3E1X2.Y2.
N4H1Z1.M8
N5G1Z-0.5F60.
N6Y0G42
N7X0F20.
N8G91G3J-0.5Z-0.0689L6
N9G90X-2.
N10G0Z1.
N11X0Y0Z0H0E0
N12M2
%
Neal