Machinist's Mate
The history gives 1964 as the establishment year and 1968 as the disestablishment year, without a month or day for either event.
- The combination applied only at E-9; it does not establish that the MM rating ended at lower pay grades.
- The record does not say what replaced the combined rating in 1968.
Source extraction notes
Malin/BUPERS source assertion: Established 1964; combination of BT and MM ratings at E-9. Normalized as merged/included. The source explicitly limits this combination to pay grade E-9; it does not assert that lower-pay-grade use of the predecessor rating ended.
Source documents (2)
Reviewed September 23, 2026 against references 1, 2 and 4.
- Charles A. Malin/Bureau of Naval Personnel, Compilation of Enlisted Ratings and Apprenticeships, U.S. Navy, 1775 to 1969 (rev. Dec. 1969)
1. #anchorm, Master Chief Steam Propulsionman (SP) entry; reproduced on archived Ohio PDF p. 10 · source dated December 1969 · cited by the explanation
Open source document (opens in a new tab)3.Charles A. Malin/Bureau of Naval Personnel, Compilation of Enlisted Ratings and Apprenticeships, U.S. Navy, 1775 to 1969 (rev. Dec. 1969) · event transcription · docs/legacy-data/navy-rating-history.jsonl:168; #anchorm, Master Chief Steam Propulsionman (SP) entry; reproduced on archived Ohio PDF p. 10
Open source document (opens in a new tab)4.Bureau of Naval Personnel: steam-propulsion master-chief grade limits and duration · #anchorm, Master Chief Steam Propulsionman; primary archived text rechecked 2026-09-23 · cited by the explanation
Open source document (opens in a new tab) - Charles A. Malin/Bureau of Naval Personnel, Abbreviations Used for Navy Enlisted Ratings (1970)
2. alphabetic abbreviation list, MM, SPCM entries · source dated 1970 · cited by the explanation
Open source document (opens in a new tab)