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Grinding and polishing operators

Official title Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic (SOC 51-4033)

Also called Grinding machine operator, Polishing machine operator, Buffing machine operator, Surface grinder operator, Lapping machine tender

In brief

In May 2025, BLS counted 67,000 US grinding and polishing operators, with median pay of $46,550 a year. Of the BLS counts since 2003, the highest was 101,530, in May 2005. The earliest figure here is an estimate of 40,000 from 1900, not measured the same way as today's count. The last full technology era for grinding and polishing operators: CNC grinding centers, 1985 to 2015. CNC grinding automation, combined with deindustrialization and offshoring of consumer-goods finishing to Asia, drove a sustained employment decline between 1990 and 2003 and continued falling.

What the sources say

Official outlook

BLS projects employment to decline 10.8% from 2025 to 2035.

BLS Employment Projections 2025-35

AI exposure studies

  • 6.5% of this job's tasks are exposed to large language models. Not a forecast of job losses. Eloundou and others, 2023
  • 0.95 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

Since the 2013 prediction

In 2013, Frey and Osborne put this job's probability of computerisation at 0.95. BLS counted 70,910 of these jobs in May 2013 and 67,000 in May 2025 (-6%, a change derived by Future History).

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.

Last updated .

Cite this page
APA

Future History. (2026, October 11). Grinding and polishing operators: jobs and pay since 1900 [Data set; data as of BLS OEWS May 2025; BLS Employment Projections 2025-35]. https://futurehistory.earth/timeline/51-4033

Chicago

Future History. "Grinding and polishing operators: jobs and pay since 1900." Data as of BLS OEWS May 2025; BLS Employment Projections 2025-35. Last modified October 11, 2026. https://futurehistory.earth/timeline/51-4033.

BibTeX

@misc{futurehistory_51_4033, author = {{Future History}}, title = {Grinding and polishing operators: jobs and pay since 1900}, year = {2026}, month = oct, howpublished = {\url{https://futurehistory.earth/timeline/51-4033}}, note = {Last updated 2026-10-11. Data as of BLS OEWS May 2025; BLS Employment Projections 2025-35}, }

The access date is today's date on your device.

drag to travel through time
187519001925195019752000now
Country
2026
Known then as Grinding Machine Operator / Grinder / Polisher (early machine shop era)
Known then as Precision Grinder / Surface Grinder Operator / Grinding Machine Operator (mass-production era)
Known then as Grinding Machine Operator / Buffing Machine Operator (postwar production era)
Known then as Machine Tool Operator, Grinding / Polishing Machine Operator (numerical-control transition era)
Known then as Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic (BLS SOC 51-4033)
Known today as Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic (BLS SOC 51-4033)
Projected to still be called Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic (BLS SOC 51-4033)
Data from the May 2025 survey
US Employment
67K
Est.

Stated in source: BLS OEWS

Official statistic
Report an error
Median Annual Wage
$46,550

≈ $45,357 in 2024 prices (derived by us, CPI-adjusted)

Official statistic
Report an error
Beat · 1874

Brown and Sharpe Manufacturing Company of Providence, Rhode Island, markets the first commercial cylindrical grinding machine, creating a distinct operator role in the American machine shop. Prior to this, grinding was a hand craft done at bench grinders or with abrasive stones. The machine imposes geometric discipline: the operator sets depth-of-cut and traverse rate, and the machine holds the workpiece on centers through a full finishing pass.

Beat · 1900

Charles Hotchkiss Norton founds the Norton Grinding Company in Worcester, Massachusetts, building a heavy-duty cylindrical grinder capable of finishing automotive crankshafts and camshafts at sixteen times the speed of prior machines. The machine weighs 15,000 pounds and is designed to hold tolerances impossible with the previous generation of grinders. Henry Ford later buys thirty-five of them for his Model T plant; in 1914 Ford remarks that "the abrasive processes are basically responsible for our ability to produce cars to sell for less than a thousand dollars."

Beat · 1938

Engis Corporation is founded; in 1948 Lapmaster Wolters is established in Chicago. Both become major suppliers of flat-lapping machines for precision sealing and bearing surfaces in automotive, hydraulic, and aerospace applications. The flat-lapping process reaches industrial maturity in the 1930s with the development of diamond-coated laps, enabling the consistent production of extremely flat reference surfaces for pump seals, valve seats, and optical flats.

Beat · 1943

Wartime precision grinding reaches its pre-electronic limit. The B-29 Superfortress's fuel-injection plungers are ground and lapped to tolerances of seven millionths (0.000007) of an inch. The War Production Board classifies grinding machine operators as essential war workers. Every aircraft engine crankshaft, naval gun barrel, and armored vehicle gearbox requires grinding operations on its critical bearing surfaces. The Arter Precision Grinding Company is mobilized specifically to produce high-precision surface grinders for the war effort.

Beat · 1954

The first commercial numerical control (NC) machine tool systems, developed at MIT and produced by Bendix Corporation, begin reaching metalworking shops. NC is adapted to cylindrical and surface grinding machines through the late 1950s, replacing the manual handwheels and crank handles that had defined the grinder's manual interface since 1874. The operator role begins to shift from continuous manual manipulation to program-entry, setup verification, and exception monitoring.

Beat · 2000

The 2000 BLS Standard Occupational Classification creates SOC 51-4033 as a distinct occupational code, separating grinding, lapping, polishing, and buffing machine operators from the broader metalworking machine operator category used in prior Census and BLS systems. Employment at the 2000 SOC introduction is approximately 108,000, down substantially from the postwar peak as deindustrialization, import competition, and CNC automation have compressed the workforce over the preceding two decades.

Beat · 2020

GrayMatter Robotics is founded to commercialize AI-guided robotic surface finishing, solving the high-mix programming barrier that had constrained robotic grinding adoption for three decades. The company's Scan&Grind system uses a 3-D scanner and physics-informed AI to autonomously generate a grinding or polishing path for an unseen part in under a minute. By 2025, GrayMatter serves aerospace and defense, automotive, marine, and industrial equipment customers. In October 2025, the company opens a 100,000-square-foot Physical AI Innovation Center in Carson, California. Critical parts that once required half an hour of manual grinding can now be finished in under ten minutes.

How to read this number

OEWS is a point-in-time survey snapshot, not a continuous time series; BLS advises against using it for year-over-year trend comparison.

Each dot is a cited figure over time; the dotted line only links them (values between aren't measured). Hollow dots are estimates.

Official statistic: Copied by a script from a statistics agency table or a published study's table, not retyped by hand. BLS figures and the forecast and exposure tables are also re-checked against that table on every data run. Researched context: Researched from the cited source rather than copied from it by a script, so it is not machine-checked yet. Spot a mistake? Each figure has a “Report an error” link.

Cited forecasts · present → 2035

Will AI replace grinding and polishing operators? What the research says

Each figure is stated by the named source; we publish no forecasts of our own. Where sources disagree, we show the disagreement rather than an average.

Each figure is stated by the named source; we publish no forecasts of our own. Where sources disagree, the spread is the honest signal.

What published forecasts say
Forecast change in the number of people doing this work, as published by each named source. Bars share one scale on every role, centred on zero and reaching the end at ±30%. Grey marks a small change, 3% or less either way.
BLS Employment Projections 2025-35
→ 2035
-10.8%
BLS National Employment Matrix, 2025-35 cycle, line for SOC 51-4033 (Grinding, lapping, polishing, and buffing machine tool setters, operators, and tenders, metal and plastic): 68.5 thousand jobs in 2025, projected 61.1 thousand in 2035, a change of -7.4 thousand (-10.8%). Matrix employment counts all jobs in the occupation, including self-employed workers (1.9% of this occupation in 2025). The average for all occupations in this cycle is +3.5%.
Official statisticReport an error
How exposed is this work to AI (research measures)
Scores as published by each study. Each row says what it measures. These measure what AI could technically do, not forecasts of jobs lost.
Frey & Osborne (2013), "The Future of Employment"
2013 study · Probability of computerisation (2013 model)
95%
probability
What this measures

Published appendix value for SOC 2010 51-4033 Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic: probability of computerisation 0.95, rank 624 of 702 (rank 1 is least computerisable). Frey and Osborne estimated in 2013, with a Gaussian-process classifier on O*NET variables, how likely the whole occupation is to be technically automatable over "some unspecified number of years, perhaps a decade or two". It is a probability for the occupation, not a share of tasks and not a forecast of jobs lost.

Official statisticReport an error
Eloundou et al. (2023), "GPTs are GPTs"
2023 study · Share of tasks exposed to LLMs (β, human-rated)
6.5%
of tasks
What this measures

Published occupation-level exposure from the paper's occ_level.csv for O*NET-SOC 51-4033.00 Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic. Shown: human-rated β = 0.065, the share of the occupation's tasks an LLM could do in at least half the time at equal quality, counting tasks that need LLM-powered software at half weight (β = E1 + 0.5 × E2). Other published measures for this occupation: human-rated α (LLM alone) 0 and γ (all LLM-assisted) 0.129; GPT-4-rated β 0.065. This measures how much of the work an LLM could touch, not how many jobs disappear.

Official statisticReport an error
Today, in this role

What's changing day to day for grinding and polishing operators

Three parts of your work where AI is already doing real lifting, and what stays yours.

AI is sitting alongside you hereLoad, fixture, and queue workpieces into robotic finishing cells (such as GrayMatter Scan&Grind or Acme robotic buffing lines), verifying part orientation and authorizing autonomous cycle start.

Load, fixture, and queue workpieces into robotic finishing cells (such as GrayMatter Scan&Grind or Acme robotic buffing lines), verifying part orientation and authorizing autonomous cycle start.[7],[4]

Where your edge is

Operators who understand how the robot's 3-D scanner builds a part model, and who can diagnose failed scans or incorrect path generation, are the gatekeepers of cell throughput; invest time learning each cell's HMI and exception-handling workflow.

AI is sitting alongside you hereInspect finished workpieces using micrometers, surface roughness profilometers, and CMM data to verify dimensional conformance and surface finish (Ra/Rz) against engineering drawings.

Inspect finished workpieces using micrometers, surface roughness profilometers, and CMM data to verify dimensional conformance and surface finish (Ra/Rz) against engineering drawings.[1],[8],[9]

Where your edge is

Develop fluency with CMM software and surface-roughness metrology; AI vision can flag deviations at line speed but a skilled operator interprets root causes and decides corrective action.

AI is sitting alongside you hereDocument production data, scrap counts, and process parameter changes in the shop-floor MES or paper travelers, maintaining traceability records required for aerospace, medical, or automotive quality systems.

Document production data, scrap counts, and process parameter changes in the shop-floor MES or paper travelers, maintaining traceability records required for aerospace, medical, or automotive quality systems.[1],[6]

Where your edge is

Learn how statistical process control (SPC) charts are generated from your machine's data feed; operators who can read a control chart and call a process drift before it produces scrap add measurable quality value.

Where grinding and polishing operators go next

Natural next steps for someone with your foundation: not exits, evolutions.

What each move takes

Industrial Engineering Technicians design and optimize the processes that grinding operators execute, including time studies, fixture design, and automation cell layout. The transition requires an associate degree or additional technical training, but experienced finishing operators bring irreplaceable shop-floor knowledge that makes them effective process engineers faster than college-only candidates.

What you'd add
  • · Associate degree or certificate in manufacturing or industrial engineering technology
  • · Time-and-motion study and process documentation (ValueStream Mapping)
  • · Robot cell layout and safety standards (ISO 10218, ANSI/RIA R15.06)
  • · CAD basics for fixture and tooling sketches (AutoCAD or SolidWorks)
What it takesA real upskill, but a natural one
Tools of the era

How has the work of grinding and polishing operators changed since 1874?

The tools that defined the work, one line per era. Select an era to see how it reshaped the work.

  • First commercial cylindrical grinders (Brown and Sharpe, 1874)

    The Brown and Sharpe cylindrical grinding machine, first marketed in 1874, transformed what had been a hand-grinding craft into a machine-operator role. The operator set the workpiece on centers, adjusted wheel depth-of-cut and traverse rate by hand wheels, and monitored the process by sound, temperature, and surface feel. Tolerances of a few thousandths of an inch were achievable, far tighter than hand methods, and opened precision metalworking to mass production for the first time. The machine created the occupation: a worker who understood abrasive mechanics, knew how to dress a wheel, and could set up a machine to hold a dimension.

  • Heavy-duty production grinders (Norton 1900, centerless grinders 1915)

    Charles H. Norton's 1900 cylindrical grinder, designed to finish automotive crankshafts and camshafts, was sixteen times faster than its predecessors and weighed thousands of pounds. Ford's purchase of thirty-five Norton grinders for the Model T plant made precision grinding structurally essential to automobile mass production: without them, tolerances close enough for interchangeable parts could not be held at production volumes. The Cincinnati Milacron centerless grinder appeared around 1915, enabling continuous bar-feed grinding without fixtures. By the 1930s, diamond-plated laps were standard in flat-lapping operations for engine seals and bearing surfaces. The grinding machine operator of this era was a production craftsman: expected to set up, dress wheels, gauge in-process, and maintain process consistency across a shift.

    Effect on the work

    Henry Ford's 1914 remark that "the abrasive processes are basically responsible for our ability to produce cars to sell for less than a thousand dollars" captured how grinding capacity multiplied output per operator and per dollar of capital. The occupation grew rapidly with the automobile industry, reaching an estimated 250,000 workers by World War II.

  • Wartime precision grinding (WWII production requirements: seven-millionths-of-an-inch tolerances)

    World War II pushed grinding technology to its pre-electronic limit. The B-29 Superfortress's fuel-injection plungers were ground and lapped to tolerances of seven millionths of an inch, unheard-of in commercial manufacturing. The War Production Board mobilized grinding machine capacity specifically; companies like Arter Precision Grinding were called on to design and build machines to meet wartime specifications. Every aircraft engine, naval gun, and armored vehicle relied on grinding operations for its moving parts. Grinding operators were classified as essential war workers, exempt from some draft calls in the early years of the war. The wartime experience professionalized the occupation: operators learned process documentation, quality inspection, and tolerance discipline that became the postwar standard.

  • Numerical control (NC) grinding (MIT/Bendix NC systems, 1954 onward)

    The first numerical control (NC) systems, developed at MIT and commercialized through the Bendix Corporation in 1954, reached grinding machines by the late 1950s and became widespread through the 1960s. NC replaced the manual crank and handwheel with a punched-tape or later digital program that controlled wheel infeed, traverse speed, and spark-out dwell. For the grinding operator, NC changed the job from continuous manual manipulation to setup and monitoring: loading the program, dressing the wheel, setting gauging offsets, and watching for tool wear or part variation. The skill required was different but not diminished: an operator who could not diagnose a bad dress, read a surface-roughness chart, or troubleshoot a spurious oversize dimension was as dangerous to quality as before.

    Effect on the work

    NC grinding increased output per operator substantially on production runs but did not reduce headcount proportionally in the 1960s and 1970s, because the technology expanded the market for precision ground parts rather than merely substituting for existing labor. The machinist shortage documented in BLS reports of the early 1980s reflected both the adoption of NC machines (which made each operator more productive) and strong demand from the defense and automotive industries.

  • CNC grinding centers (closed-loop gauging, adaptive wheel compensation)

    By the mid-1980s, CNC grinding centers with real-time in-process gauging had supplanted most manual and NC grinding in automotive and aerospace production. Siemens SINUMERIK and Fanuc CNC controls allowed operators to enter dimensional targets and compensation offsets digitally; the machine adjusted infeed automatically as the part approached size. Adaptive control systems (spindle-load monitoring) moderated wheel infeed to prevent burn and overload without operator intervention. The 1990s added wheel-wear compensation algorithms that tracked cumulative material removal and automatically adjusted the infeed offset, reducing the number of measurement interruptions per shift. For the operator, the job concentrated on setup correctness, wheel selection and dressing quality, and catching the process drifts that the adaptive systems could not fully handle independently.

    Effect on the work

    CNC grinding automation, combined with deindustrialization and offshoring of consumer-goods finishing to Asia, drove a sustained employment decline between 1990 and 2003 and continued falling. The grinding operations that survived in the US concentrated in aerospace, medical devices, and automotive powertrain, where part complexity and quality requirements kept the work onshore.

  • AI-guided robotic finishing cells (GrayMatter Scan&Grind, adaptive force control, 2020 onward)

    GrayMatter Robotics, founded in 2020, commercialized a qualitatively new approach to grinding and polishing automation: a robot equipped with a 3-D scanner that can model an unseen part in under a minute, generate a custom grinding or polishing path using physics-informed AI, and execute it with real-time adaptive force control. This addresses the principal barrier that had kept robotic grinding limited to low-mix production runs for decades: each part needed a custom robot program, and programming took longer than the job. GrayMatter's Scan&Grind and Scan&Polish systems handle high-mix production, including aerospace castings and composite structures, without manual path programming. Acme Manufacturing and similar vendors offer comparable robotic buffing and deburring cells for high-volume automotive applications. The operator role in these cells shifts from tending the grinding process to loading parts, monitoring the robot's scan quality, and handling exceptions the cell's AI cannot resolve. Critical parts that once required many minutes of manual grinding can now be finished in under ten minutes with robotic cells.

    Effect on the work

    The transition toward robotic finishing cells, combined with continued CNC automation, is the primary driver of the BLS projection of a 7% employment decline for all metal and plastic machine workers through 2034. The 51-4033 occupation is among the more exposed sub-categories because surface finishing is a relatively structured, repeatable process once part geometry is known, making it amenable to robotic automation at a faster rate than complex multi-step machining.

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Grinding, Lapping, Polishing, and Buffing Machine Tool Setters, Operators, and Tenders, Metal and Plastic employment and pay by year

On record since1874
Latest US employment67,000 (May 2025)Source: BLS OEWS May 2025Official statisticReport an error
Latest US median pay$46,550 (May 2025)Source: BLS OEWS May 2025Official statisticReport an error
Outlook-10.8% by 2035Source: BLS Employment Projections 2025-35Official statisticReport an error

In other countries

The latest figure each country's statistics agency publishes for this job. Each uses its own occupation definition, survey basis and currency, so the numbers are not directly comparable with each other or with the US figures.

  • Canada (NOC 94106)

    Employment, 2020
    8,665, Statistics Canada Census 2021 Official statistic Report an errorStatistics Canada Census of Population 2021: number of persons with employment income in NOC 94106 Machining tool operators, Canada, reference year 2020. A recipients basis (anyone with employment income during the year), slightly broader than a point-in-time employed count. Statistics Canada Open Licence.
    Median pay, 2020
    C$53,600, Statistics Canada Census 2021 Official statistic Report an errorStatistics Canada Census of Population 2021 (Table 98-10-0586): median employment income for NOC 94106 Machining tool operators, Canada, reference year 2020, full-year full-time workers (the basis comparable to the US OEWS full-time median). Statistics Canada Open Licence.
View all 28 years of cited US data, each linked to its source
YearUS employmentAnnual pay (median unless marked)SourceReport
190040,000n/aEst., Charles H. Norton Researched contextReport
1943250,000n/aEst., Arter Precision Grinding Machines Researched contextReport
1953200,000$3,900Est., FRASER / BLS Bulletin 1130 Researched contextReport
1990130,000n/aEst., BLS Researched contextReport
2000n/a$24,360BLS OEWS 2000 Official statisticReport
200397,660$26,630BLS OEWS May 2003 Official statisticReport
200498,770$27,440BLS OEWS May 2004 Official statisticReport
2005101,530$27,740BLS OEWS May 2005 Official statisticReport
2006100,010$28,080BLS OEWS May 2006 Official statisticReport
200796,730$28,640BLS OEWS May 2007 Official statisticReport
200891,990$29,460BLS OEWS May 2008 Official statisticReport
200981,740$30,270BLS OEWS May 2009 Official statisticReport
201070,120$30,670BLS OEWS May 2010 Official statisticReport
201170,450$31,280BLS OEWS May 2011 Official statisticReport
201269,510$31,620BLS OEWS May 2012 Official statisticReport
201370,910$32,220BLS OEWS May 2013 Official statisticReport
201470,130$32,660BLS OEWS May 2014 Official statisticReport
201573,570$32,840BLS OEWS May 2015 Official statisticReport
201674,600$32,890BLS OEWS May 2016 Official statisticReport
201774,600$33,480BLS OEWS May 2017 Official statisticReport
201871,870$34,850BLS OEWS May 2018 Official statisticReport
201976,810$36,100BLS OEWS May 2019 Official statisticReport
202069,570$36,880BLS OEWS May 2020 Official statisticReport
202167,750$37,550BLS OEWS May 2021 Official statisticReport
202273,800$38,910BLS OEWS May 2022 Official statisticReport
202375,260$42,610BLS OEWS May 2023 Official statisticReport
202470,110$45,190BLS OEWS May 2024 Official statisticReport
202567,000$46,550BLS OEWS May 2025 Official statisticReport
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