CNC Turning

CNC Lathe Machine Parts for Automotive and Aerospace

We turn shafts, bushings, fittings and housings from bar stock and near-net blanks. Tolerances hold at ±0.005 mm, finishes run down to Ra 0.2 μm, and mill-turn centers cut cross holes in the same setup.

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Ø400 mm rotary table±0.005 mmRa 0.2–0.8 μm4,000 mm max lengthNo MOQ3–5 day shipping

CNC Lathe Technical Specifications Terminology

16Mill-turn centers

127High-precision CNC machines

±0.005 mmAchievable turning tolerance

99.99%Qualification rate

Common Problems

Where Turned Parts Go Wrong

Four failures we see most often on lathe parts.

Roundness drifts on long shafts

A shaft with a 6:1 length-to-diameter ratio deflects between centers. The diameter mikes fine at both ends and reads oversize in the middle. The assembly presses in tight, then seizes once the bearing runs warm.

Concentricity lost across two setups

A housing turned on one machine and drilled on another picks up the chuck's runout twice. The bore sits 0.03 mm off the OD. Dowel pins no longer line up, and the whole bracket needs rework.

Thread and surface callouts ignored

A print calls out Ra 0.8 μm on a sealing face and a rolled thread instead of a cut one. The shop turns it on a manual lathe, leaves Ra 3.2 μm, and the O-ring weeps under pressure at the test bench.

Material traceability missing

Aerospace and automotive programs need mill test certificates per batch. Without them, incoming inspection quarantines the lot. The line stops while paperwork gets chased across three suppliers.

How We Turn

Turning Built Around One Setup

Fewer setups, less stack-up, tighter parts.

Single-Setup Turning

Mill-Turn Centers Cut Cross Features Without Re-Chucking

Our 16 mill-turn centers combine turning and milling in one program. A shaft with flats, cross holes and a keyway comes off the machine complete. Because the part never leaves the spindle, concentricity between the OD and the cross feature stays inside 0.01 mm.

That matters most on parts with a tight true-position callout between a turned diameter and a milled feature. Two-setup work stacks the chuck runout twice. One setup stacks it once.

1
Ø400 mm rotary tableIndexed milling on turned diameters up to 400 mm.
2
Live toolingDrill, tap and mill across the part axis without moving it.
3
Bar feedersUnattended runs on small-diameter parts down to Ø5 mm.

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Aerospace CNC Machining Prototype High Accuracy Custom

Dimensional Control

How We Hold ±0.005 mm on Production Runs

Turning tolerance is not a machine spec, it is a process result. Thermal growth, tool wear and chuck pressure all move the diameter over a shift. We set the process window from the first article and monitor it through the run.

In-process gauging catches drift before the diameter leaves the band. If a feature trends toward the limit, the operator adjusts the offset, not the print. Every lot ships with a dimensional report when the drawing calls for one.

1
First article inspectionFull dimensional layout before the run releases.
2
In-process monitoringDiameter and length checked at set intervals.
3
100% final inspectionEvery part measured before it is packed.

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Material Guide

Which Material Fits Your Turned Part

Pick by service condition, not by habit.

Material	Typical Turned Parts	Watch Out For
6061-T6 aluminium	Housings, spacers, manifolds	Low hardness, galls on fine threads
7075 aluminium	High-load brackets, fittings	Higher cost, notch sensitive
303 stainless	Shafts, bushings, fittings	Free-machining sulfur, limited weld use
17-4PH stainless	Valve bodies, actuator parts	Needs H900/H1025 aging after turning
C36000 brass	Connectors, valve stems, inserts	Dezincification in wet service
Ti-6Al-4V	Aerospace fasteners, bushings	Low thermal conductivity, tool wear
Inconel	Hot-section fittings	Work hardens, slow speeds required
PEEK / POM	Seals, insulators, wear rings	Thermal expansion, fixturing pressure

What We Turn

Turning Services Under One Roof

One supplier from bar stock to finished, inspected parts.

CNC Turning

Bar-fed and chucked turning on 2-axis lathes for simple round parts. Diameters from Ø5 mm up, with live tooling available on the mill-turn side.

Mill-Turn Machining

16 mill-turn centers handle turned parts with cross holes, flats and slots. One setup keeps the OD and the milled feature concentric inside 0.01 mm.

Swiss-Type Turning

Small-diameter parts with long slender geometry, such as pins and ferrules. Guide-bushing support controls deflection on high length-to-diameter ratios.

Threading and Grooving

Cut, rolled and ground threads to UN, metric and NPT forms. Groove widths held to the print, including undercut and relief grooves.

Surface Finishing

Anodizing, electroless nickel, black oxide, bead blasting and polishing. Laser marking with a minimum character height of 1.5 mm.

Rapid Prototyping

Functional turned samples in days for design validation and fit checks. Same process window as production, so the sample predicts the run.

Capability Range

Turning Capacity at a Glance

Numbers you can check against your drawing.

Parameter	Range	Notes
Turning tolerance	±0.005 mm (±0.0002 in)	Held through production runs
Fine finish	Ra 0.2–0.8 μm	Sealing faces and bearing seats
Standard finish	Ra 0.8–1.6 μm	General turned surfaces
Maximum part length	4,000 mm	Long shafts and tie rods
Rotary table	Ø400 mm	Indexed milling on turned parts
Minimum diameter	Ø5 mm	Bar-fed small parts
Order quantity	1 to 10,000+ parts	No minimum order quantity
Lead time	Quote in 12 h, ship in 3–5 days	After drawing release

Why GreatLight

What We Bring to a Turning Program

Six reasons engineers move their lathe work here.

15Y

15 Years in Turning

Founded in 2011 with three wholly-owned plants and 7,600 m² of manufacturing space. The process window on hard materials comes from that history, not from a spec sheet.

±0.005

Tolerance Discipline

Tight dimensional control on production runs, not just on the first article. Offset adjustments happen during the run so the diameter stays in band.

100%

Inspection Before Shipment

Raw material check, in-process monitoring and final inspection on every lot. Dimensional and material reports on request.

12H

Quote and DFM in 12 Hours

Send a drawing and get a quotation plus free DFM analysis within 12 hours. Production can start within 24 hours of approval.

Four Certifications

ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. Automotive and medical programs get the paperwork they require.

MTC

Material Traceability

All material comes from ISO-certified suppliers with mill test certificates for every batch. No quarantined lots waiting on paperwork.

7,600 m²Manufacturing space

150Technicians

3Wholly-owned plants

<2%Historical late-delivery rate

What Industries Require

Turning Results by Industry

Aluminum-machining-for-automotive-engine-parts — Automotive and EV
IATF 16949:2016 process control with mill test certificates per batch.
±0.005 mm
Ra 0.8–1.6 μm
MTC per batch

6a7c7b8a05b1f9f10be636920614a594 — Aerospace
Inconel and Ti-6Al-4V turned fittings with full dimensional reports on request.
Ti-6Al-4V
Inconel
100% inspection

aerospace-prototyping — Medical Devices
ISO 13485:2016 workflow for turned components with fine surface finishes.
Ra 0.2–0.8 μm
ISO 13485
Clean deburring

automotive-prototyping-manufacturing — Industrial Machinery
Long shafts and tie rods turned up to 4,000 mm with concentricity held.
4,000 mm
Ø400 mm table
No MOQ

FAQs

Questions Engineers Ask About Lathe Parts

What is the smallest turned part you can make?

We run bar-fed parts down to Ø5 mm on the small lathes. Below that, the guide bushing and the chucking load become the limit, and a Swiss-type setup is usually the better route.

Send the drawing and we will tell you whether turning is the right process or whether the part should be milled or stamped instead.

Can you hold ±0.005 mm on a production run, not just the first article?

Yes, within the process window set at first article. Thermal growth and tool wear move the diameter over a shift, so we monitor the feature in-process and adjust the offset during the run.

Features outside that window, such as very long slender shafts, will be quoted with a realistic tolerance based on the length-to-diameter ratio.

Do you turn parts with cross holes and milled flats?

Yes. The 16 mill-turn centers cut turned and milled features in one setup, so concentricity between the OD and the cross feature stays inside 0.01 mm.

If the part only needs a single cross hole and a loose true-position callout, a two-setup route is cheaper and we will quote it that way.

Which materials do you keep in stock for turning?

Aluminium 6061, 6061-T6, 2024, 5052, 6063, 6082 and 7075. Stainless 303, 304, 316, 316L, 17-4PH and 440C. Steel 1018, 1045, 4130, 4140 and 4340. Brass C36000, copper C110, titanium TA2 and TC4, plus PEEK, POM and PA plastics.

All material comes from ISO-certified suppliers with mill test certificates for every batch.

How do you control surface finish on sealing faces?

Sealing faces are turned with a dedicated finishing pass and measured for Ra before the run releases. Fine finishes run Ra 0.2–0.8 μm.

If the print calls out a softer finish than Ra 0.8 μm, tell us at quote stage. It changes the tool, the feed and the cycle time, and we would rather price it correctly than discover it at inspection.

What lead time should I plan for?

Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours of approval, and parts ship in 3–5 days.

Long slender parts and hard materials such as Inconel take longer because of the lower cutting speeds. We give the schedule with the quote.

Can you work from a sample instead of a drawing?

Yes, if the sample is dimensionally stable and we can measure it. We reverse-engineer the geometry, flag any features that cannot be verified, and send a drawing for your approval before cutting metal.

For parts with critical fits, a drawing is still the better input. A worn sample can carry the wear into the new batch.

How is my design data protected?

Uploads are secure and confidential. We sign an NDA on request before drawings are shared, and access to customer files is limited to the engineers on the job.

We do not publish customer names, part numbers or drawings.