01
Runout grows along the shaft
A slender shaft deflects when tailstock pressure is too high or feed per revolution is too aggressive. The first article measures fine, then part 200 shows 0.03 mm of runout and the bearing will not seat.
Precision Turning Service
Lathe Machining Parts
We turn shafts, bushings, fittings, and threaded parts on 127 CNC machines, including 16 mill-turn centers and a Ø400 mm rotary table. Tolerances hold at ±0.005 mm. Order one piece or ten thousand.
±0.005 mmØ400 mm rotary tableRa 0.2 μmNo MOQ12-hour quoteISO 9001 / IATF 16949
127High-precision CNC machines
16Mill-turn centers
±0.005 mmTurning tolerance
99.99%Qualification rate
Common failure points
Where turned parts go wrong
Most problems show up after the first article passes. These are the four we see most.
02
Threads gauge tight or loose
Thread depth depends on tool wear and spindle speed. Without in-process gauging, pitch diameter drifts across a run. Mating parts either bind or rattle, and the whole batch gets sorted by hand.
03
Bore finishes vary batch to batch
Insert grade, coolant pressure, and depth of cut all shift the surface finish inside a bore. If your seal or bushing needs Ra 0.4 μm and the shop ships Ra 1.6 μm as machined, the part fails at assembly.
04
Second-operation setup loses position
Moving a part from the lathe to a mill for cross-holes or flats reintroduces position error. Two setups can add 0.02 mm of stack-up, which is enough to miss a dowel pin location.
How we hold tolerance
Turning built around the feature that matters
We read the drawing for the critical feature first, then pick the machine and setup that protects it.
Setup strategy
Mill-turn centers cut setups, not corners
Sixteen mill-turn centers let us face, turn, bore, and cross-mill in one clamping. There is no second fixture, so the position error from re-chucking never enters the stack. That matters on parts with a bolt circle, a cross-hole, or flats that must sit square to a journal.
For long shafts we use the Ø400 mm rotary table and steady rest support. Feed, speed, and tailstock pressure are recorded on the setup sheet and reused on the next run, so part 1 and part 500 come off the same way.
- 1One clampingTurn and mill features in the same setup, no re-datum.
- 2Setup sheetSpeeds, feeds, and pressures documented per part number.
- 3In-process gaugingCritical diameters checked during the run, not only at the end.
Material and finish
Turning titanium and Inconel without scrapping the run
Titanium and nickel alloys work-harden fast. We keep the tool engaged, use high-pressure coolant, and program conservative depths. That is slower per part, but it keeps the surface intact and the insert alive long enough to finish the run.
Turning covers aluminium 6061, 7075, and 2024; stainless 303, 316L, and 17-4PH; steel 1045 and 4140; brass C36000; titanium TC4 and TA2; and plastics from POM to PEEK. Finishes include anodizing, electroless nickel, black oxide, and bead blasting.
- 1Work-hardening alloysInconel 718, TC4, and 17-4PH run on dedicated programs.
- 2Finish controlRa 0.2–0.8 μm when a seal face needs it.
- 3Deburr and markEdges broken to drawing; laser marking from 1.5 mm character height.
Selection guide
Which turning route fits your part
Use the part geometry and tolerance to pick the route before quoting.
| Part type | Recommended route | Why |
|---|---|---|
| Straight shaft, Ø6–80 mm | CNC lathe, 2-axis | Lowest cost per part on simple profiles |
| Cross-hole or flats | Mill-turn center | One clamping, no second-operation error |
| Ø up to 400 mm, short | Ø400 mm rotary table | Face and bore in one setup |
| Long slender shaft | Lathe with steady rest | Controls deflection over length |
| Prototype, 1–10 pcs | Mill-turn, no hard fixture | No tooling cost, starts within 24 hours |
| Hardened 45–60 HRC | Turn soft, then grind | Turning alone will not hold the tolerance |
Related services
What we run alongside turning
Turning is often one step. These are the services that finish the part.
01
CNC Milling & Turning
Milled and turned features on the same part number.
02
5-Axis CNC Machining
Complex geometry that a lathe cannot reach.
03
Rapid Prototyping
One to ten pieces for fit checks and design review.
04
Surface Finishing
Anodizing, plating, black oxide, blasting, polishing.
05
Metal Die Casting
Transition from turned prototype to cast volume.
06
Sheet Metal Fabrication
Brackets and enclosures that pair with turned parts.
Scope
Turning scope and what is included
Standard scope on every turned part order.
| Item | Range / detail |
|---|---|
| Diameter range | Ø0.5–400 mm on turned features |
| Tolerance | ±0.005 mm on critical diameters |
| Surface finish | Ra 0.2–0.8 μm fine; Ra 1.6–3.2 μm as machined |
| Materials | Aluminium, stainless, steel, brass, titanium, Inconel, plastics |
| Order size | One prototype to 10,000+ part runs |
| Inspection | 100% before shipment, reports on request |
Why GreatLight
What you get on the order
Fifteen years of turning, three plants, one process sheet per part.
15Y
Turning since 2011
Three wholly-owned plants and 7,600 m² of floor space.
±0.005
Held tolerance
Micrometer values in mm, ±0.0002 in if your drawing is imperial.
127
CNC machines
Including 16 mill-turn and 16 simultaneous 5-axis centers.
12H
Quote turnaround
Quotation and free DFM analysis within 12 hours.
24H
Production start
Cutting can begin within 24 hours of approval.
100%
Inspection
Raw material check, in-process monitoring, final inspection.
7,600 m²Manufacturing space
150Technicians
3Plants, Dongguan and Singapore
<2%Historical late-delivery rate
Typical applications
Where these parts go
Aerospace fittings
Turned housings and fittings in 17-4PH and Inconel 718 with traceable material certs.
- ±0.005 mm
- Ra 0.4 μm
- Material certs
Automotive and EV shafts
Motor shafts and sensor bosses turned in one clamping to keep runout low.
- IATF 16949
- 12-hour quote
- 10,000+ runs
Medical device bushings
316L bushings with burr-free bores and passivated surfaces for cleanroom assembly.
- ISO 13485
- Ra 0.2 μm
- 100% inspection
FAQs
Questions engineers ask before ordering
When is turning cheaper than milling for a round part?
If the part is mostly axisymmetric and the dominant features are diameters, bores, or threads, turning wins on cycle time and tool cost. A mill has to interpolate every diameter.
Once the part needs several cross-holes, pockets, or a prismatic body, the balance shifts. We often run those on a mill-turn center so both feature types come off in one setup.
What is the smallest diameter you can turn?
Turned features down to Ø0.5 mm are possible on the smaller machines, but a Ø0.5 mm pin will not hold ±0.005 mm over any real length. Thin sections move with cutting force.
Tell us the length-to-diameter ratio and the tolerance together. Below 3:1 we are comfortable. Past 10:1 we add a steady rest, reduce the depth of cut, and may need two passes.
Can you hold ±0.005 mm on a long shaft?
Not across the whole length without support. The tolerance applies to the diameter at the measured point, not to a 500 mm span centre-to-centre.
For long parts we turn between centers or with a steady rest, then verify with a micrometer at several stations. If your drawing needs a tight concentricity over length, send it and we will quote the extra setup honestly.
Do you turn titanium and Inconel?
Yes. We run TC4, TA2, Inconel 718, and 17-4PH on dedicated programs with high-pressure coolant.
These alloys work-harden, so we keep the insert engaged and avoid dwelling. Expect slower cycle times and higher insert cost than 303 stainless. The surface quality is worth it for seal faces and fatigue-loaded parts.
What surface finish can you achieve on a bore?
Ra 0.2–0.8 μm is achievable on a bored surface with the right insert, coolant, and feed. Ra 1.6–3.2 μm is the normal as-machined result.
Bore finish also depends on length. A deep bore with a long boring bar will chatter before it polishes. If you need Ra 0.4 μm at 8:1 depth, say so at quote time, not after.
Is there a minimum order quantity?
No. We run from one prototype to 10,000+ part runs on the same process sheet.
A single piece still goes through material check, in-process monitoring, and final inspection. The setup cost is what makes a one-off more expensive per part than a run, not a minimum.
How do you handle second operations like cross-holes?
We prefer to do them on a mill-turn center so the part never leaves the spindle. That removes the re-datum error entirely.
If the geometry forces a separate mill setup, we use a dedicated fixture with a locating bore, and we inspect the first article for position before the run continues.
Can you work from a sample instead of a drawing?
Yes, if the sample is in good enough condition to measure. We reverse-engineer the dimensions and send a drawing for your approval before cutting.
Without a drawing there is no tolerance to hold, so we ask you to confirm the critical dimensions. That step prevents a batch that fits the sample but not the assembly.
Send your drawing, get a turning quote
Upload a STEP or PDF and we return a quotation with free DFM analysis within 12 hours.
12-hour quote100% inspectionNo minimum order quantityNDA on request
