The objective of the 60° Stub specification is to provide a definition for a thread form that is no longer supported by ANSI or Federal standards.

This specification applies to the dimensioning and specification of 60° Stub threads at all EMS centers. All dimension listed in this document are in inches.

The definition of terms in this specification are the same as those in FED-STD-H28, Screw-Thread Standards for Federal Service, and ASME B1.1

The angle between the flanks of the thread is 60 degrees. The threads are truncated top and bottom to have a basic height of 0.433p, a basic thickness of 0.5p, and aresymmetrical about a line perpendicular to the axis of the screw. The roots are deepened by 0.02p (equivalent to .04p on the diameter) to avoid interference at the root with the crest of the mating thread. The result is a thread
height of 0.453p.

A pitch diameter allowance of .04p is applied to the nut.
Figure 1 illustrates the basic 60° thread form and how it evolves into the final profile of the 60° stub thread.