NPFC - MIL-S-7742
SCREW THREADS, STANDARD, OPTIMUM SELECTED SERIES: GENERAL SPECIFICATION FOR
|Publication Date:||25 July 1991|
This specification covers the requirements for a selected series of standard Unified and Unified Miniature screw threads, classes 3A and 3B of FED-STD-H28/2 and FED-STD-H28/5 for general aerospace and similar high-tech application. The purpose of this specification is to:
a. Relate verification requirements to the intended service application of the threaded product.
b. Provide default verification requirements if not otherwise specified.
c. Allow the use of methods of verification found in FED-STD-H28/20 and ANSI/ASME B1.3M.
d. Encourage the use of new or more efficient methods of verification, such as on-line or statistical process controls. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: ASD/ENES, Wright-Patterson AFB OH 45433-6503 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.
This specification is to be used for reprocurement of threaded products used in designs released prior to the date of this specification.
For new designs the following applies:
a. Use MIL-S-8879 for fatigue applications.
b. Use FED-STD-H28/2 for general non-fatigue applications.
c. Use FED-STD-H28/5 for thread sizes smaller than 0.060 inch.
d. For class 2 threads, use the applicable section of FED-STD-H28.