CNC Machinist III

Job Description

Job Description

Department: CNC Mill or Lathes

Position Title: CNC Machinist III

FLSA: · Non-Exempt / Hourly ·

Reports to: Plant Manager

The CNC Machinist III is the shop's most capable and self-directed machinist — the person who takes the difficult job, the tight tolerance, the new part, or the problem machine and returns it to production without hand-holding. The role owns independent setup and prove-out across all assigned workcenters, dimensional quality at the machine, and the development of less-experienced machinists. The Machinist III works from prints and models rather than proven paperwork alone, authors and corrects programs at the CNC control, and makes the process decisions — tooling, workholding, sequence, speeds and feeds — rather than executing someone else's. This is the top rung of the machinist ladder and the primary feeder into the programming track; proficiency is measured against the Machinist Skills Matrix using the 0–4 Skill Level Key.

• Perform complete setups from scratch on all assigned workcenters — workholding, tooling, offsets, program load, and first-piece qualification — without supervision.
• Select and document tooling, insert grade, workholding, and operation sequence for new or problem parts.
• Prove out new and revised programs at the control, correcting toolpaths, feeds, speeds, and offsets to bring parts into tolerance; run production to print and router, holding dimensional quality, surface finish, and cycle time across the shift.
• Write, edit, and optimize G-code and M-code at the CNC control, including subprograms, canned cycles, and parametric / macro programming for part families.
• Own dimensional quality at the machine using micrometers, bore gauges, indicators, height and thread gauges, surface plate, and optical comparator.
• Interpret prints and models including GD&T datums, feature control frames, true position, and tolerance stack-up; support first-article inspection, interpret CMM reports, translate findings into corrections, and contain suspect material per quality procedure.
• Diagnose and correct chatter, poor finish, dimensional drift, tool wear and breakage, and control alarms; separate process problems from machine problems and partner with maintenance on the latter. Perform operator-level preventive maintenance — way lube, coolant concentration, chip and filter management, machine cleanliness.
• Train and mentor Machinist I and II personnel, sign off competency as authorized, and author or correct setup sheets so setups are repeatable by others.
• Drive cycle-time and scrap reduction, tooling standardization, and 5S; maintain accurate labor, quantity, and scrap reporting.
• Follow and enforce all safety rules, lockout/tagout, machine guarding, and PPE requirements; correct unsafe conditions and report near-misses.

The competencies below are required in this role. Proficiency expectations for each are defined and assessed in the Machinist Skills Matrix.

Skills Matrix Competency

Skills Matrix Competency

Safety & shop practices

Speeds, feeds & chip load

Shop math & trigonometry

CNC programming — control level

Print reading & blueprint interpretation

Macros / parametric programming

GD&T & tolerance interpretation

Advanced CNC (multi-axis, mill-turn)

Measurement & inspection

Prove-out & first-article support

Materials & machinability

Troubleshooting & problem solving

Manual machining (lathe / mill / grind)

Machine technology — workcenters

CNC machine operation

Documentation & setup sheets

CNC setup

Training & mentoring

Workholding & fixturing

Continuous improvement / scrap reduction

Tooling & insert selection

Equipment Proficiency

Required — Setup 3–4 / Run 4: CNC lathes, including live-tool and bar-fed turning centers; CNC vertical machining centers; CNC horizontal machining centers.

Development target — Setup 2 / Run 3: CNC mill-turn and multi-axis turning centers; twin-spindle lathes. Active development on at least one mill-turn platform is expected.

As assigned: CNC OD grinding and CNC gear equipment; manual lathes and mills, grinders, shapers, saws, presses, and deburr stations for rework and fixture work. Ratings apply to the workcenters listed on the machinist’s qualification card; machines not on the card are outside the scope of the title until trained and signed off.

Behavioral: works independently with minimal direction; communicates clearly with programming, quality, and maintenance; teaches patiently; owns and corrects mistakes; dependable attendance.

• Minimum five years of CNC machining in a job-shop or low-to-mid-volume precision environment, including at least two years of independent setup work — or two years at CNC Machinist II with all Skills Matrix minimums above met and verified.
• Demonstrated history of holding tolerances to ±0.0005″ and surface finishes to print on production work, with documented fluency on the shop’s CNC controls including G/M-code editing and offset management.
• Preferred: mill-turn or multi-axis setup and programming; Mastercam or ESPRIT CAM familiarity (required to advance to Associate CNC Programmer); Okuma OSP control and its intelligent technologies; prior experience training or leading machinists.

• Required: high school diploma or GED.
• Preferred: machining certificate or diploma from a technical school, completion of a formal machinist apprenticeship, or NIMS credentials in turning, milling, or CNC programming; OEM or distributor control training, macro programming, or mill-turn training.
• Ongoing: maintains current internal certifications for assigned workcenters, hoist or forklift certification where applicable, and annual safety training.

Standing / walking

Continuous — the majority of an 8- to 12-hour shift on a concrete floor. Overtime, shift coverage, and occasional weekend work as production requires.

Lifting / carrying

Frequent to 25 lbs; occasional to 50 lbs unassisted. Hoists and lift assists required above 50 lbs for chucks, fixtures, and workholding. Occasional pushing of carts, pallet jacks, and chip hoppers.

Bending / reaching

Frequent bending, reaching, and kneeling to load parts, set tooling, and access machine interiors and coolant systems.

Hand & wrist use

Continuous fine-motor and grip activity — tool setting, wrenching, gauge handling, keypad and MPG use.

Vision & hearing

Close vision and depth perception sufficient for precision measurement, tool setting, and surface-plate layout (correctable acceptable); hearing sufficient to detect alarms, tool-condition changes, and verbal warnings in a high-noise area.

Work is performed on an active manufacturing floor. These exposures are inherent to the role and are controlled through engineering controls, administrative practice, and required PPE.

Exposure

Description & Controls

Noise

Elevated machine, air, and impact noise. Hearing protection required in posted areas; hearing conservation program participation where monitoring indicates.

Metalworking fluids & chemicals

Coolant and cutting-oil mist and skin contact; way lube, hydraulic and spindle oils, solvents, degreasers, and layout dye. Machine enclosures and local exhaust where fitted, nitrile gloves, barrier cream, prompt washing. Governed by the hazard communication program.

Metal chips & particulate

Sharp turnings, swarf, and airborne fines from cutting, grinding, and deburring. Safety glasses with side shields at all times; face shield for grinding and chip clearing; cut-resistant gloves when handling chips.

Moving machinery

Rotating spindles, chucks, bar feeders, turrets, pallet changers, and automatic tool changers. Machine guarding, interlocks, and lockout/tagout are mandatory; no reaching into an operating envelope.

Thermal, slip & trip

Hot chips, workpieces, and heated coolant; coolant and oil films, chips, hoses, and air lines on walking surfaces. Slip-resistant safety footwear required; spills cleaned immediately; 5S maintained.

Ergonomic & environment

Repetitive motion, sustained standing, and awkward setup postures; anti-fatigue matting, lift assists, and job rotation available. Non-climate-controlled shop, equipment vibration, and powered industrial truck traffic in aisles.

Minimum PPE: safety glasses with side shields, hearing protection in posted areas, slip-resistant footwear, and task-appropriate gloves. Loose clothing, jewelry, and unrestrained long hair are prohibited near rotating equipment.