UNS threads represent unique combinations of diameter and pitch, adhering to the Unified Thread Standard but with specific tolerances. The designation of UNS threads includes the basic format previously described, along with precise limits of size to ensure proper fit and performance.
For example:
0.250-24 UNS-3A (21)
MAJOR DIA: 0.2500-0.2428
PITCH DIA: 0.2229-0.2201
MINOR DIA MAX: 0.205