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Manufacturing

CNC Machinist

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CNC Machinists set up and operate computer-controlled milling machines, lathes, and machining centers to cut metal parts to precise dimensional tolerances. They read engineering drawings, select tooling, write or edit G-code programs, set machine offsets, and inspect finished parts using precision measurement tools — producing components that must meet specifications as tight as a few thousandths of an inch.

Role at a glance

Typical education
Associate degree in machining technology or NIMS apprenticeship
Typical experience
Entry-level to Journeyman (requires years of hands-on training)
Key certifications
NIMS Machining Level 1/2, Mastercam Certification, Autodesk Fusion 360 Machining
Top employer types
Aerospace manufacturers, defense contractors, medical device companies, job shops
Growth outlook
Stable demand; structural talent shortage due to retiring workforce
AI impact (through 2030)
Augmentation — automation handles high-volume simple parts, but demand is increasing for skilled machinists capable of managing complex 5-axis programming and precision metrology.

Duties and responsibilities

  • Set up CNC mills and lathes: mount and indicate workholding fixtures, install and measure tooling, enter work offsets and tool length compensations
  • Write and edit G-code programs at the control (Fanuc, Haas, Mazak, Okuma) or using CAM software (Mastercam, Fusion 360) for new parts and first articles
  • Execute the first-article machining run, proving out the program, verifying dimensions, and adjusting offsets to bring parts into tolerance
  • Inspect machined parts using calipers, micrometers, CMM (coordinate measuring machine), and surface finish gauges against the engineering drawing
  • Select cutting tools — end mills, inserts, drills, boring bars — appropriate for the material, tolerance, and surface finish required
  • Monitor cutting conditions (speeds, feeds, depth of cut) and adjust to prevent tool wear, chatter, or work-hardening on difficult alloys
  • Maintain machine tool accuracy by checking and adjusting backlash, performing laser calibrations, and coordinating scheduled preventive maintenance
  • Document setups in setup sheets: tooling list, offsets, speeds/feeds, fixture positions — so the job can be run again without starting from scratch
  • Perform in-process inspection during long-run production jobs, monitoring dimensional drift and adjusting offsets to hold tolerance
  • Interpret GD&T callouts on drawings — concentricity, perpendicularity, true position — and verify compliance with appropriate measurement techniques

Overview

CNC Machinists turn metal stock into precision components. Given a blueprint, a block of aluminum, titanium, or steel, and a CNC machining center, a skilled machinist produces a part that fits and functions correctly because every surface, hole, and feature was cut to specification.

The job is part programming, part setup, part troubleshooting, and part inspection. On new jobs, the machinist programs the part (or edits a CAM-generated program), proves the setup by cutting the first piece and measuring every critical dimension, and adjusts offsets until the part is good. On production jobs, the work shifts to monitoring: watching tool wear, checking dimensions at defined intervals, and catching the moment when something is drifting before scrap is made.

Tool selection and cutting parameters are where machinist expertise becomes visible. An experienced machinist running Inconel or titanium knows exactly how fast to cut, what depth to take, and when to change the insert before the surface finish degrades — knowledge that comes from years of feedback between the cut sound, the chips, and the measurement results. That expertise is hard to document and harder to replicate.

In aerospace and defense shops, the documentation burden is substantial. Every operation, every tool change, every inspection result may need to be logged against a traveler that follows the part. First articles require full AS9102 inspection documentation. Non-conformances require paperwork. Machinists who treat documentation as part of the job rather than an interruption to it are genuinely more employable in high-value sectors.

Shop floor culture matters. A good machinist respects the equipment, keeps the area clean, communicates problems to supervisors and engineers promptly, and shares what they know with less experienced machinists. The ones who hoard knowledge or cut corners on setups create problems that outlast their tenure.

Qualifications

Education and training paths:

  • NIMS (National Institute for Metalworking Skills) apprenticeship — 4 years, the comprehensive path
  • Associate degree in machining technology, precision manufacturing, or manufacturing engineering technology
  • Community college CNC certificate program (12–18 months) — faster entry, less breadth
  • Military machining occupational specialty (MOS) with equivalent training

Certifications:

  • NIMS Machining Level 1 and 2 — industry-recognized credentials covering milling, turning, and measurement
  • NIMS CNC Milling and Turning credentials — specific to CNC operation and programming
  • AS9100 awareness training — expected in aerospace-supply-chain shops
  • Mastercam Certification or Autodesk Fusion 360 Machining certification for CAM programming

Technical skills:

  • CNC controls: Fanuc (most common), Haas, Mazak Mazatrol, Okuma OSP, Siemens Sinumerik
  • CAM software: Mastercam, Fusion 360, GibbsCAM, NX CAM
  • Precision measurement: micrometers (0–6"), calipers (digital and vernier), bore gauges, depth mics, thread gauges
  • CMM operation: Zeiss Contura, Hexagon Global, PC-DMIS programming basics
  • Materials knowledge: 6061 and 7075 aluminum, 304/316 SS, 4140 steel, titanium 6Al-4V, Inconel 718
  • Workholding: vises, 5C collets, face plates, custom fixtures — indicating and tramming

Physical requirements:

  • Sustained standing and physical activity during setup
  • Close visual acuity for reading drawings and measuring parts
  • Safe handling of coolants, cutting fluids, and metal chips

Career outlook

CNC machining is one of the more durable skilled trades in U.S. manufacturing. Despite automation concerns, job shops, aerospace manufacturers, medical device companies, and defense contractors consistently report difficulty finding skilled machinists — a gap that has persisted for years and shows no signs of closing naturally.

The talent shortage is structural. The workforce that entered machining in the 1980s and 1990s is retiring faster than new entrants are replacing them, and CNC machining doesn't have the recruiting appeal of software or healthcare careers among younger workers. Shops that actively invest in training and apprenticeship programs are managing better than those relying on the labor market to supply skilled machinists.

The skill content of the role is increasing, not decreasing. Lights-out machining for high-volume simple parts is real, but the frontier of what needs a skilled machinist keeps moving. 5-axis machining of complex aerospace structures, medical implant precision machining, and prototype machining for product development are all growing work categories that require genuine skill and judgment.

Salary progression is meaningful for machinists who invest in programming and metrology skills. An entry machinist earns $42–52K; a journeyman machinist with setup and programming capability earns $58–72K; a senior machinist or shop foreman with multi-axis CAM programming experience can reach $80–95K. At large aerospace and defense suppliers, overtime and shift differentials can push annual earnings significantly above base.

The career can evolve toward CNC programmer, manufacturing engineer, process engineer, or shop manager. Some experienced machinists start their own job shops — the barrier to entry with a used machining center has dropped significantly, and skilled shops with reliable quality are in consistent demand from larger manufacturers.

Sample cover letter

Dear Hiring Manager,

I'm applying for the CNC Machinist position at [Company]. I'm a journeyman machinist with six years of experience at [Shop Name], a job shop that does primarily aerospace and defense prototype and low-volume production work.

My background is 3- and 4-axis milling on Haas and Fanuc-controlled VMCs, with some turning on a Doosan 2600. I program my own parts in Mastercam and edit the posted G-code at the machine. The work I've been doing includes first articles for new programs — writing the programs, proving setups, and generating the AS9102 documentation that goes with the CMM report.

The material I've put the most time into is 7075 aluminum and 6Al-4V titanium for structural brackets and fittings. Titanium taught me how much feeds and speeds matter for tool life — I had to rebuild my understanding of chip load and cutting speed from scratch after burning through a set of expensive end mills on my first titanium job. I've since developed our shop's standard cutting parameter sheets for titanium and Inconel, which we now use as the starting point for new programs on those materials.

I'm looking for a position with more 5-axis work exposure. Your vertical machining and 5-axis mill turn combination is the kind of setup I want to learn, and I'm willing to start on 3-axis work while I qualify on the 5-axis equipment. I hold NIMS CNC Milling Level 2 and I'm studying for the CMM programming credential.

I'd appreciate the chance to bring my portfolio of setup sheets and first-article reports to an interview.

[Your Name]

Frequently asked questions

What machining education or training do employers look for?
Apprenticeship programs (typically 4 years through NIMS or union-affiliated programs) are the gold standard for well-rounded machinists. Two-year associate degrees in machining technology or precision manufacturing are a faster academic path. Many machinists learn through vocational programs and on-the-job training. NIMS (National Institute for Metalworking Skills) credentials are widely recognized and worth pursuing at any stage of a machining career.
What is the difference between a CNC operator and a CNC machinist?
A CNC operator loads parts, pushes cycle start, and unloads parts — running a proven program without setup responsibility. A CNC machinist sets up the machine, proves out programs, adjusts offsets to achieve tolerance, and troubleshoots problems. Machinists are paid significantly more and require significantly more skill. Some job postings blur the distinction; the actual scope becomes clear when you ask who writes the programs and who sets the offsets.
What is G-code and do all machinists need to know it?
G-code is the programming language that instructs a CNC machine — move here, rotate at this speed, cut to this depth. CAM software (Mastercam, Fusion 360) generates G-code automatically from 3D models, but machinists who can read and edit the code directly can fix problems at the machine rather than waiting for a programmer. For 3- and 4-axis work, conversational G-code editing at the machine control is a practical skill; for 5-axis and complex work, CAM software is essential.
What materials are hardest to machine and why does it matter?
Titanium, Inconel, hardened stainless, and tool steels are notoriously difficult — they generate heat rapidly, work-harden, and wear tooling fast. Machinists who can consistently hold tolerance on these materials are considerably more valuable than those limited to aluminum and mild steel. Aerospace and medical device applications heavily use these challenging materials, which is one reason those sectors pay more.
Is CNC machining being automated away?
Lights-out machining (automated, unattended production) has been growing for high-volume, low-mix parts. But the setup, first-article, troubleshooting, and low-volume work that makes up a large portion of job shop and aerospace machining still requires skilled human judgment. The machinist role is shifting toward higher-value activities — programming, quality control, process engineering — and away from purely repetitive operation. Machinists who invest in programming and metrology skills will find the role durable.
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