Does anyone know the most important for produce a thread mill just it is just need to control the pitch only?? let say i need to produce a M16 x pitch 1.5 thread mill then the crest length is 0.1875mm, root length is 0.375mm and thread depth is 0.812mm. So, this three tolerance should be how many?? Or it is not so important?? Any expert can give me some idea??