# Engine and Other Machine Assemblers

US SOC code 51-2031. Markdown version of https://futurehistory.earth/timeline/51-2031

## In brief

In May 2025, [BLS](https://www.bls.gov/oes/special-requests/oesm25nat.zip) counted **34,000** US engine and other machine assemblers, with median pay of **$53,710** a year. The earliest figure here is [an estimate](https://en.wikipedia.org/wiki/Morgan_Iron_Works) of **3,000** from 1865, not measured the same way as today's count. The last full technology era for engine and other machine assemblers: Coordinate measuring machines and computer-aided assembly verification, 1985 to 2010.

Figures: Official statistic (latest count and pay); Researched context (earliest figure).

## What the sources say

### Official outlook

BLS projects employment to decline 17% from 2025 to 2035. Source: [BLS Employment Projections 2025-35](https://data.bls.gov/projections/nationalMatrix?queryParams=51-2031&ioType=o) (Official statistic).

### AI exposure studies

- **0.82** estimated probability that the whole occupation could be computerised, over an unspecified number of years. Not a forecast of job losses. [Frey and Osborne, 2013](https://oms-www.files.svdcdn.com/production/downloads/academic/The_Future_of_Employment.pdf) (Official statistic)

### Since the 2013 prediction

In 2013, Frey and Osborne put this job's probability of computerisation at 0.82. BLS counted **39,620** of these jobs in May 2013 and **34,000** in May 2025 (-14%, a change derived by Future History). Figures: Official statistic.

Data as of BLS OEWS May 2025; BLS Employment Projections 2025-35. BLS publishes these counts as yearly survey snapshots and cautions against reading them as a precise trend. In May 2021 BLS changed how it estimates these counts (a model-based method using three years of survey data) and moved fully to the 2018 occupation codes, so part of a change across 2021 can come from the method rather than the work.

## Engine and Other Machine Assemblers employment and pay by year

- On record since: 1838
- Latest US employment: 34,000 (May 2025). Source: BLS OEWS May 2025 [4]
- Latest US median pay: $53,710 (May 2025). Source: BLS OEWS May 2025 [6]
- Outlook: -17% by 2035. Source: BLS Employment Projections 2025-35 [15]

### All 27 years of cited US data

| Year | US employment | Annual pay (median unless marked) | Source |
| --- | --- | --- | --- |
| 1865 | 3,000 (estimate) | n/a | Est., Wikipedia [1] |
| 1900 | 45,000 | n/a | Decennial Census 1900 [2] |
| 1943 | 200,000 (estimate) | n/a | Est., Connecticut History / Pratt and Whitney [3] |
| 2000 | n/a | $33,748 | BLS CPS 2000 [5] |
| 2003 | 50,410 | $32,400 | BLS OEWS May 2003 [4] |
| 2004 | 45,730 | $34,800 | BLS OEWS May 2004 [4] |
| 2005 | 49,430 | $34,770 | BLS OEWS May 2005 [4] |
| 2006 | 45,120 | $33,250 | BLS OEWS May 2006 [4] |
| 2007 | 41,100 | $31,500 | BLS OEWS May 2007 [4] |
| 2008 | 39,270 | $32,660 | BLS OEWS May 2008 [4] |
| 2009 | 34,080 | $34,490 | BLS OEWS May 2009 [4] |
| 2010 | 33,310 | $36,310 | BLS OEWS May 2010 [4] |
| 2011 | 36,670 | $36,420 | BLS OEWS May 2011 [4] |
| 2012 | 40,750 | $36,110 | BLS OEWS May 2012 [4] |
| 2013 | 39,620 | $37,300 | BLS OEWS May 2013 [4] |
| 2014 | 38,330 | $38,310 | BLS OEWS May 2014 [4] |
| 2015 | 38,700 | $39,600 | BLS OEWS May 2015 [4] |
| 2016 | 38,150 | $41,210 | BLS OEWS May 2016 [4] |
| 2017 | 37,770 | $43,390 | BLS OEWS May 2017 [4] |
| 2018 | 48,200 | $44,380 | BLS OEWS May 2018 [4] |
| 2019 | 45,980 | $45,660 | BLS OEWS May 2019 [4] |
| 2020 | 41,510 | $45,770 | BLS OEWS May 2020 [4] |
| 2021 | 45,990 | $47,440 | BLS OEWS May 2021 [4] |
| 2022 | 50,120 | $50,850 | BLS OEWS May 2022 [4] |
| 2023 | 47,960 | $50,270 | BLS OEWS May 2023 [4] |
| 2024 | 38,420 | $52,540 | BLS OEWS May 2024 [4] |
| 2025 | 34,000 | $53,710 | BLS OEWS May 2025 [4] |

## Sources (70)

### Employment series

1. [Wikipedia: Morgan Iron Works (employment 1865); Wikipedia: Etna Iron Works (employment peak 1860s)](https://en.wikipedia.org/wiki/Morgan_Iron_Works), Wikipedia / primary sources cited therein
2. [US Census Bureau: 1900 Census, Volume VII Manufactures, Part 1 (United States by Industries)](https://www.census.gov/library/publications/1902/dec/vol-07-manufactures.html), US Census Bureau
3. [Connecticut History / Pratt and Whitney: "The Early Years of the Pratt and Whitney Aircraft Company" (workforce 3,000 to 40,000, 1940-1943)](https://connecticuthistory.org/the-early-years-of-the-pratt-and-whitney-aircraft-company/), Connecticut Humanities / Connecticut History
4. BLS OEWS, national cross-industry estimates (flat file), Bureau of Labor Statistics. Editions: [2003](https://www.bls.gov/oes/special-requests/oesm03nat.zip), [2004](https://www.bls.gov/oes/special-requests/oesm04nat.zip), [2005](https://www.bls.gov/oes/special-requests/oesm05nat.zip), [2006](https://www.bls.gov/oes/special-requests/oesm06nat.zip), [2007](https://www.bls.gov/oes/special-requests/oesm07nat.zip), [2008](https://www.bls.gov/oes/special-requests/oesm08nat.zip), [2009](https://www.bls.gov/oes/special-requests/oesm09nat.zip), [2010](https://www.bls.gov/oes/special-requests/oesm10nat.zip), [2011](https://www.bls.gov/oes/special-requests/oesm11nat.zip), [2012](https://www.bls.gov/oes/special-requests/oesm12nat.zip), [2013](https://www.bls.gov/oes/special-requests/oesm13nat.zip), [2014](https://www.bls.gov/oes/special-requests/oesm14nat.zip), [2015](https://www.bls.gov/oes/special-requests/oesm15nat.zip), [2016](https://www.bls.gov/oes/special-requests/oesm16nat.zip), [2017](https://www.bls.gov/oes/special-requests/oesm17nat.zip), [2018](https://www.bls.gov/oes/special-requests/oesm18nat.zip), [2019](https://www.bls.gov/oes/special-requests/oesm19nat.zip), [2020](https://www.bls.gov/oes/special-requests/oesm20nat.zip), [2021](https://www.bls.gov/oes/special-requests/oesm21nat.zip), [2022](https://www.bls.gov/oes/special-requests/oesm22nat.zip), [2023](https://www.bls.gov/oes/special-requests/oesm23nat.zip), [2024](https://www.bls.gov/oes/special-requests/oesm24nat.zip), [2025](https://www.bls.gov/oes/special-requests/oesm25nat.zip)

### Wage series

5. [BLS Current Population Survey: Median usual weekly earnings of full-time wage and salary workers, Engine and Other Machine Assemblers, 2000 ($649/week annualized to $33,748)](https://www.bls.gov/cps/earnings.htm), U.S. Bureau of Labor Statistics
6. BLS OEWS, national cross-industry estimates (flat file), Bureau of Labor Statistics. Editions: [2003](https://www.bls.gov/oes/special-requests/oesm03nat.zip), [2004](https://www.bls.gov/oes/special-requests/oesm04nat.zip), [2005](https://www.bls.gov/oes/special-requests/oesm05nat.zip), [2006](https://www.bls.gov/oes/special-requests/oesm06nat.zip), [2007](https://www.bls.gov/oes/special-requests/oesm07nat.zip), [2008](https://www.bls.gov/oes/special-requests/oesm08nat.zip), [2009](https://www.bls.gov/oes/special-requests/oesm09nat.zip), [2010](https://www.bls.gov/oes/special-requests/oesm10nat.zip), [2011](https://www.bls.gov/oes/special-requests/oesm11nat.zip), [2012](https://www.bls.gov/oes/special-requests/oesm12nat.zip), [2013](https://www.bls.gov/oes/special-requests/oesm13nat.zip), [2014](https://www.bls.gov/oes/special-requests/oesm14nat.zip), [2015](https://www.bls.gov/oes/special-requests/oesm15nat.zip), [2016](https://www.bls.gov/oes/special-requests/oesm16nat.zip), [2017](https://www.bls.gov/oes/special-requests/oesm17nat.zip), [2018](https://www.bls.gov/oes/special-requests/oesm18nat.zip), [2019](https://www.bls.gov/oes/special-requests/oesm19nat.zip), [2020](https://www.bls.gov/oes/special-requests/oesm20nat.zip), [2021](https://www.bls.gov/oes/special-requests/oesm21nat.zip), [2022](https://www.bls.gov/oes/special-requests/oesm22nat.zip), [2023](https://www.bls.gov/oes/special-requests/oesm23nat.zip), [2024](https://www.bls.gov/oes/special-requests/oesm24nat.zip), [2025](https://www.bls.gov/oes/special-requests/oesm25nat.zip)

### Tool eras

7. [Wikipedia: Morgan Iron Works (founded 1838 as T. F. Secor and Co.; production of marine steam engines, 1838-1867)](https://en.wikipedia.org/wiki/Morgan_Iron_Works), Wikipedia
8. [Wikipedia: Etna Iron Works (Civil War-era engine manufacturing; employment 2,000 workers; largest marine engines in the US)](https://en.wikipedia.org/wiki/Etna_Iron_Works), Wikipedia
9. [Connecticut Humanities: "The Early Years of the Pratt and Whitney Aircraft Company" (Wasp engine 1925; wartime workforce 3,000 to 40,000)](https://connecticuthistory.org/the-early-years-of-the-pratt-and-whitney-aircraft-company/), Connecticut Humanities
10. [GE Aerospace: "How GE's Magnificent Seven Established the Evendale Complex" (Evendale 1948; J47 production; 1,200 to 8,000 workers)](https://www.geaerospace.com/news/articles/100-year-anniversary/how-ges-magnificent-seven-established-evendale-complex), GE Aerospace
11. [University of Wisconsin-Stevens Point: "U.S. Manufacturing Employment: A Long-Term Perspective" (fabricated metals and machinery: 4.2 million in 1979, 2.6 million by 2019)](https://blog.uwsp.edu/cps/2025/01/29/u-s-manufacturing-employment-a-long-term-perspective/), University of Wisconsin-Stevens Point
12. [BLS: "Forty Years of Falling Manufacturing Employment" (manufacturing employment decline from 1979 peak through 2015)](https://www.bls.gov/opub/btn/volume-9/forty-years-of-falling-manufacturing-employment.htm), Bureau of Labor Statistics
13. [BLS National Employment Matrix 2024-34: 51-2031 Engine and Other Machine Assemblers (38,400 in 2024; 30,300 projected 2034; -21.1%)](https://data.bls.gov/projections/nationalMatrix?queryParams=51-2031&ioType=o), Bureau of Labor Statistics
14. [Aero-Mag: "Automation Helps Pratt and Whitney Cut Engine Assembly in Half" (Alfred robot; GTF high-pressure compressor rotor assembly)](https://www.aero-mag.com/automation-helps-pratt--whitney-cut-engine-assembly-in-half), Aero-Mag

### Forecasts and exposure studies

15. [BLS Employment Projections 2025-35, National Employment Matrix: 51-2031 Engine and other machine assemblers (2025: 33.5 thousand; 2035: 27.8 thousand; -17.0%)](https://data.bls.gov/projections/nationalMatrix?queryParams=51-2031&ioType=o), Bureau of Labor Statistics
16. [Frey & Osborne (2013), "The Future of Employment: How Susceptible Are Jobs to Computerisation?", Appendix (SOC 51-2031 Engine and Other Machine Assemblers: probability 0.82, rank 449 of 702)](https://oms-www.files.svdcdn.com/production/downloads/academic/The_Future_of_Employment.pdf), Oxford Martin School, University of Oxford

### Historical notes

17. [Wikipedia: Morgan Iron Works (founding 1838; production record; workforce)](https://en.wikipedia.org/wiki/Morgan_Iron_Works), Wikipedia
18. [Connecticut Humanities: "The Early Years of the Pratt and Whitney Aircraft Company" (founding 1925; Wasp engine; Navy order)](https://connecticuthistory.org/the-early-years-of-the-pratt-and-whitney-aircraft-company/), Connecticut Humanities
19. [Lynn Legacies: "General Electric" (GE Lynn history; April 18, 1942 first jet run; peak employment 13,000 in 1985)](https://lynnlegacies.org/general-electric/), Lynn Legacies
20. [GE Aerospace: "How GE's Magnificent Seven Established the Evendale Complex" (1948 founding; J47 production; 1,200 to 8,000 workers)](https://www.geaerospace.com/news/articles/100-year-anniversary/how-ges-magnificent-seven-established-evendale-complex), GE Aerospace
21. [University of Wisconsin-Stevens Point: "U.S. Manufacturing Employment: A Long-Term Perspective" (1979 peak 19.5 million; fabricated metals and machinery 4.2 million in 1979)](https://blog.uwsp.edu/cps/2025/01/29/u-s-manufacturing-employment-a-long-term-perspective/), University of Wisconsin-Stevens Point
22. [Aero-Mag: "Automation Helps Pratt and Whitney Cut Engine Assembly in Half" (Alfred robot; GTF compressor rotor; assembly time halved)](https://www.aero-mag.com/automation-helps-pratt--whitney-cut-engine-assembly-in-half), Aero-Mag

### Predecessors & successors

23. [Wikipedia: Morgan Iron Works (T. F. Secor and Co., 1838; marine engine assembly workforce)](https://en.wikipedia.org/wiki/Morgan_Iron_Works), Wikipedia
24. [Connecticut Humanities: "The Early Years of the Pratt and Whitney Aircraft Company" (wartime workforce expansion; assembler skill base)](https://connecticuthistory.org/the-early-years-of-the-pratt-and-whitney-aircraft-company/), Connecticut Humanities

### Present-day analysis

- [Eloundou et al. 2024 — GPTs are GPTs (Science)](https://arxiv.org/abs/2303.10130), accessed 2026-05-21
- [O\*NET 30.3 — US Department of Labor](https://www.onetcenter.org/database.html), accessed 2026-05-21

How to read these figures: https://futurehistory.earth/methodology. Every figure links to its own source; gaps stay gaps.