| Thread Gage Calibration Advisory Alert
With respect to the requirements specified in applicable ASME B1 and FED-STD-H28 standards, "Certifications of Calibration" issued for threaded plug and ring gages which have been measured, calibrated and certified for pitch diameter size via the Best Wire / MOW method ONLY , and found to be IN-TOLERANCE , same are to be considered INVALID when measurement, calibration and certification for verification for conformance to Class "X" or Class "W" tolerances, as they may apply, have NOT been performed on pitch / lead and flank angles.
For Answers to thread gage correlation and measurement uncertainty problems, contact us .
Attn: MIL-S-8879, UNJ Screw Thread Producers and Users1. CANCELLATION NOTICE: Effective 24 February 2003 with Notice 3
MIL-S-8879C, dated 25 July 1991, and AMENDMENT 1, dated 2 September 1992, are
Hereby cancelled, and superceded by the Society of Automotive Engineers (SAE)
Aerospace Specification AS8879. Threads identified as Application Category
"Other Thread" in MIL-S-8879C are identified as "Category 1" threads in
AS8879. Threads identified as Application Category "Safety critical Thread"
i n MIL-S-8879C are identified as "Category 2" threads in AS8879.
Click here for MIL-S-8879C, NOTICE 3 2. SUPERSESSION DOCUMENT: AS8879
This standard was generated to provide an alternative to the inactive government specification MIL-S-8879 for screw threads - UNJ profile, inch.
This standard has been revised to focus on the design requirements for screw threads - UNJ profile
Inch. Procurement information not directly related to the design standard, such as product acceptance
and quality assurance, have been removed.
A whitepaper has been developed to provide some history on the development of screw thread
Standards (MIL-S-8879 and AS8879) and the rationale for the content of AS8879 Revision C. This
whitepaper will be published in the future by the SAE as an Aerospace Information Report (AIR5926).
To Order SAE AS8879 Document:
Tel: 877-606-7323 (Inside USA & Canada)
Tel: 724-776-4970 (Outside USA)
Order a copy online
3. AS8879 serves the simultaneous requirements of FAA & DoD
- FAA - Regulatory per AC 21-41A and 14 CFR part 21.
Click here for AC 21-41A
- DoD - Procurement Information.
4. USE GUIDE
Click here to view Johnson Gage Use Guide for MIL-S-8879 & FAA AC No. 21-41A
There have been several previous non-military versions of AS8879. These are not to be used as the superceding document for MIL-S-8879C. Threads identified as Application Category "Other Thread" in MIL-S-8879C are identified as "Category 1" threads in AS8879. Threads identified as Application Category "Safety Critical Thread" in MIL-S-8879C are identified as "Category 2" threads in AS8879.
6. TECHNICAL SUPPORT:
Johnson Gage is in the process of compiling a complete workbook of specifications associated with the changes mentioned above. This book will be available in the next few weeks. If you are interested in this workbook, contact Johnson Gage through this web site. We will contact you know when we start taking orders for the workbook.
INSPECTION / EVALUATION GAGING SYSTEMS FOR EXTERNAL & INTERNAL SCREW THREAD CHARACTERISTICS