For that size range you can use an ISCAR MGCH 06 or MGCH 08 with a thread cutting insert, the inserts are available in the two most common thread angles.
Tony at Jurassic Tools has a few in stock at an excellent price - http://www.jurassictools.com/store/s...re&phrase=mgch
My only connection with Jurassic tools is as a very satisfied customer,

- Nick