01
Is your shaft oval, not round?
A part that should be round comes back with 0.03 mm lobing. It happens when a thin-wall tube is gripped too hard or the chuck pressure is never adjusted. Assembly then binds and you scrap the lot.
Precision Turning
CNC Turning Service
Turned parts cut from bar stock on lathes and mill-turn centers. Diameters to Ø813 mm, lengths to 1,575 mm, held to ±0.005 mm. Send a drawing or STEP file; you get a quote and a DFM review within 12 hours.
±0.005 mm toleranceØ813 mm max diameter16 mill-turn centersRa 0.2–0.8 μm finishNo minimum order quantityQuote in 12 hours
127High-precision CNC machines
±0.005 mmStandard turned-part tolerance
15 yearsTurning parts since 2011
99.99%Qualification rate
Turning problems
Where turned parts usually go wrong
These are the failures we see on incoming drawings every week.
02
Threads that will not gauge
The pitch diameter drifts mid-run and the mating nut only goes halfway. On a turned part this usually means tool wear was not tracked or the thread was single-pointed without a gauge check. Rework means re-chasing every piece.
03
Bore and OD out of concentricity
The bore sits 0.05 mm off the outside diameter. If the part is flipped between two chuckings without a soft jaw or a sub-spindle, that offset is baked in. Bearings press in crooked and the shaft runs hot.
04
Finish that fails a seal
A turned surface at Ra 3.2 μm will not hold an O-ring. Too many shops ship as-machined and call it done. If the drawing calls Ra 0.8 μm or finer, the feed rate and insert nose radius have to be set for it.
Our approach
How we hold turned parts to the drawing
Bar stock in, gauge-checked parts out, with the process fixed before the first chip.
Rigidity first
Correct workholding decides the roundness
Roundness on a turned part is a workholding problem before it is a cutting problem. Thin-wall tubes and long slender shafts deflect under chuck pressure, so we cut soft jaws to the actual bar diameter and set grip force per job rather than per machine. On parts with a length-to-diameter ratio past 4:1 we bring in a tailstock or a steady rest.
For milled features on a turned part, 16 mill-turn centers let us drill, cross-hole and slot in the same setup. One chucking means the bolt circle stays concentric with the bore, and you avoid the second-op fixture that adds error.
- 1Soft jaws per jobBored to the bar diameter so thin walls do not crush.
- 2Sub-spindle pickoffBack-side features cut without a second chucking.
- 3Bar feeder to Ø80 mmUnattended runs on high-volume turned parts.
Tolerance control
±0.005 mm is a process, not a promise
Holding ±0.005 mm across a production run means controlling temperature, tool wear and spindle growth. We rough and finish in separate passes, let the part stabilize, then take the finish cut. In-process gauging flags drift before the feature leaves tolerance, not after.
GD&T callouts are read off your drawing and checked with the method they imply: concentricity on a bench center, position on a CMM, surface finish with a profilometer. Inspection reports come with the shipment when you ask for them.
- 1Rough and finish separatedRemoves heat and stress before the final pass.
- 2In-process gaugingDiameter and length checked while the part is still in the machine.
- 3100% inspectionEvery part checked before it is packed.
Fit check
When turning is the right process
Use this to decide before you send the file.
| Part shape | Better process | Why |
|---|---|---|
| Cylindrical, axial features | CNC turning | One chucking holds concentricity |
| Prismatic, flat pockets | CNC milling | Turning cannot reach the corners |
| Turned OD plus side holes | Mill-turn | Both features in one setup |
| Thin-wall tube under 1 mm | Turning with soft jaws | Chuck pressure must be controlled |
| Deep bore over 5× diameter | Turning plus boring bar | Standard tooling will chatter |
| Threads, grooves, knurls | CNC turning | Single-point and form tools cover it |
| Fine detail under Ø0.5 mm | Consider EDM | Cutting forces bend small features |
What we run
Turning work we take on
One shop for the turned part and the operations around it.
01
CNC Turning
Bar-fed and chucked work on lathes and mill-turn centers. Shafts, bushings, fittings, spacers, threaded studs and valve bodies, from one piece to 10,000+.
02
Mill-Turn Parts
Cross holes, flats and slots cut in the same setup as the turning. Keeps the bolt circle true to the bore on hydraulic and pneumatic fittings.
03
5-Axis Machining
16 simultaneous 5-axis centers for contoured turned parts and features that a 3-axis setup cannot reach at the right angle.
04
Rapid Prototyping
Turned prototypes for fit and function checks before tooling. Same inspection routine as production, so the numbers carry over.
05
Surface Finishing
Anodizing, plating, black oxide, bead blasting and polishing. Laser marking down to 1.5 mm character height for traceability.
06
Assembly & Inspection
Pressed-in bearings, O-rings and sub-assembly, plus CMM reports and material certificates on request.
Capability
Turning capacity at a glance
Numbers we build to, not marketing ranges.
| Item | Range | Note |
|---|---|---|
| Max turned diameter | Ø813 mm | Larger diameters on request |
| Max turned length | 1,575 mm | Steady rest for long shafts |
| General tolerance | ±0.005 mm | ISO 2768 unless stated |
| As-machined finish | Ra 1.6–3.2 μm | Standard turned surface |
| Fine finish | Ra 0.2–0.8 μm | On request, adds a pass |
| Threads | Any standard size | Custom threads need review |
| Minimum order | 1 piece | Prototype to 10,000+ runs |
| Quotation | Within 12 hours | Includes free DFM analysis |
Why GreatLight
What you get with the parts
Data points, not adjectives.
15Y
Turning since 2011
Fifteen years on turned parts, three wholly-owned plants and 7,600 m² of manufacturing space in Dongguan and Singapore.
±0.005
Millimeter tolerance
Held on metals per ISO 2768 unless your drawing calls tighter. GD&T callouts checked with the method they imply.
127
CNC machines
16 simultaneous 5-axis centers, 16 mill-turn centers and 12 four-axis mills. Capacity for both one-offs and long runs.
12H
Quote turnaround
Quotation and free DFM analysis back within 12 hours. Production can start within 24 hours of approval.
99.99%
Qualification rate
100% inspection before shipment, with raw material check, in-process monitoring and final inspection.
4
Certifications
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. NDA available on request.
7,600 m²Manufacturing space
150Technicians on staff
3–5 daysTypical shipping window
<2%Historical late-delivery rate
Applications
Turned parts by industry
Electronics
Copper and brass contacts, pins and heat-spreader parts turned to tight diameter control.
- ±0.005 mm
- Ra 0.8–1.6 μm
- C101, C110, C36000
Automotive & EV
Bushings, sensor housings and motor shafts run under IATF 16949 process control.
- IATF 16949
- 100% inspection
- 3–5 day ship
Medical Devices
Stainless turned components with burr-free bores and clean surface finishes.
- ISO 13485
- 316L, 17-4PH
- Ra 0.2–0.8 μm
Industrial Machinery
Rollers, spacers and fittings up to 1,575 mm long, held concentric to the bore.
- 1,575 mm length
- Ø813 mm max
- Mill-turn setups
FAQs
Questions engineers ask about turning
What is the difference between a CNC lathe and a turning center?
A CNC lathe turns a part against a single spindle with axial tools. A turning center adds a turret with live tooling, a sub-spindle and often a Y axis, so milling, drilling and back-side work happen in the same cycle.
For a simple shaft with a thread, a lathe is enough. If the part needs cross holes or a milled flat, a turning center removes the second operation and the error that comes with it.
How does a CNC lathe actually cut a part?
Bar stock or a blank is gripped in a chuck or collet and spun. A single-point tool moves along the Z and X axes to face, turn, bore and thread the profile the program describes.
Tool offsets set the cutting edge position, so the machine compensates for wear and inserts without touching the program. That is why a turned diameter can be corrected mid-run.
What tolerance can you hold on turned parts?
±0.005 mm on metals per ISO 2768, tighter where the drawing calls it out and the geometry allows. Length, diameter and position are checked separately.
Very thin walls, long slender shafts and soft plastics will move more. Send the drawing and we will tell you which dimensions are realistic before you commit.
Which materials do you turn most often?
Aluminum 6061-T6, 2024, 7075 and 6082; stainless 303, 304, 316L, 17-4PH and 440C; steel 1018, 1045, 4140 and 4340; copper C101 and C110; brass C36000; titanium TC4; and plastics like POM, PEEK and PA.
Free-machining grades such as 303 stainless and C36000 brass cut cleanly and hold tight diameters. Titanium and Inconel need slower speeds and more tool changes.
Can you cut threads and knurls on a turned part?
Any standard thread size, cut with single-point tooling or a die head. Custom thread forms require a manual quote review because the tooling may need to be made.
Knurling depends on the material and the wall thickness. On thin-wall parts knurling can distort the bore, so we may suggest a cut knurl or a rolled feature instead.
What surface finish should I specify?
As-machined turning lands around Ra 1.6–3.2 μm. A seal or bearing seat usually needs Ra 0.8–1.6 μm, and sliding or optical surfaces need Ra 0.2–0.8 μm.
Finer finish costs an extra pass and sometimes a different insert. Specify the finish where it matters instead of calling the whole part fine.
Do you have a minimum order quantity?
No minimum. We run one prototype and we run 10,000+ piece orders on the same machines and inspection routine.
Small quantities are quoted individually since setup time dominates the cost. Larger runs get bar feeders and unattended cycles.
How fast can I get turned parts?
Quote and free DFM analysis within 12 hours. Production can start within 24 hours of approval, and parts ship in 3–5 days.
That window assumes the drawing is released and the material is in stock. Exotic alloys and custom threads add a step because they need manual review.
Send a drawing, get turned parts
Upload your CAD file and we will come back with a quotation, a DFM review and any tolerance we think should change.
12-hour quote100% inspectionNo minimum orderNDA on request
