scope:

This Standard establishes the basic triangular profile for the UNJ thread form, provides a system of designations, lists the standard series of diameter-pitch combinations for diameters from 0.600 to 6.000 in., and specifies limiting dimensions and tolerances.

It specifies the characteristics of the UNJ inch series of threads having 0.15011P to 0.18042P designed radius at the root of the external thread, and also having the minor diameter of the external and internal threads increased above the ASME B1.1 UN and UNR thread forms to accommodate the external thread maximum root radius.