CNC Turning Services – Precision Turned Parts
Precision CNC turning of shafts, bushings, pins, sleeves and threaded components in carbon steel, stainless steel, aluminum, brass, POM, PEEK and titanium. ±0.005mm concentricity, Ra 0.4μm finishes, mill-turn capability for cross features, MOQ 1 piece from our China workshop.
Free Consultation±0.005mm
Concentricity
5 Days
Prototype Lead Time
1 Piece
MOQ
Up to Ø65mm
Bar Production
Materials
| Grade | Properties | Typical Applications |
|---|---|---|
| Carbon Steel (45# / S45C / 1045) | Tensile 600 MPa, Yield 355 MPa, good machinability, readily heat-treatable, lowest cost engineering steel. Best turned with carbide inserts at moderate speeds. | Shafts, axles, studs, pins, bushings, gears, valve stems, general mechanical hardware |
| Stainless Steel (SUS303 / 304 / 316L) | SUS303: free-machining, chip-breaking; SUS304: excellent corrosion resistance, 520 MPa tensile; SUS316L: superior chemical resistance with molybdenum. Work-harden rapidly – sharp positive-rake tooling required. | Food equipment shafts, valve components, marine hardware, medical fittings, chemical pump parts |
| Aluminum (AL6061-T6 / AL7075-T6 / AL5052) | 6061: versatile, anodizes well; 7075: highest strength; 5052: excellent forming. All free-machining at high speeds with excellent surface finish and low cutting forces. | Spacers, pulleys, light-duty shafts, sensor housings, optics mounts, decorative hardware |
| Brass (H62 / H59 / C3604) | C3604 free-cutting brass: outstanding chip control and surface finish, ideal for high-speed automatic turning; H62: good strength for structural turned parts. | Connector bodies, valve parts, fittings, threaded inserts, decorative components, switchgear parts |
| Engineering Plastics (POM / PEEK / PA66 / PC) | POM: excellent dimensional stability, low friction; PEEK: high-temperature 260°C, chemical resistant; PA66: wear resistant, common for bearings; PC: tough, transparent grades available. | Insulating bushings, valve seats, food-contact parts, bearings, wear pads, electronic insulators |
| Copper & Titanium (T2 / Gr2 / Gr5) | T2 copper: highest conductivity, needs sharp tooling to avoid smearing; Ti Gr2/Gr5: high strength-to-weight, low thermal conductivity requiring flood coolant and controlled cutting speed. | Electrical terminals, heat-exchanger parts, aerospace fasteners, medical implants, racing hardware |
Process Parameters
| Parameter | Standard Range |
|---|---|
| Maximum Swing Diameter (Chuck) | Ø400mm over bed |
| Maximum Turning Length | Up to 1500mm with steady rest support |
| Bar Stock Capacity (Automatic) | Ø3mm – Ø65mm, lengths to 3000mm |
| Dimensional Tolerance (Standard) | ±0.02mm |
| Dimensional Tolerance (Precision) | ±0.005mm on critical diameters with in-process measurement |
| Concentricity / Runout | ≤0.005mm between centers; ≤0.01mm in chuck production |
| Surface Roughness (As-turned) | Ra 0.8μm – 3.2μm; Ra ≤0.4μm achievable with finishing pass or polishing |
| Roundness (Ground Finishes) | ≤0.003mm with centerless grinding where specified |
| Thread Capability | M3 – M60 metric, UNC/UNF, BSP, NPT, trapezoidal; single-point and tap/thread-mill |
| Cross Features (Live Tooling) | Flats, keyways, cross-holes, milled slots, hexagons, eccentric features in one setup |
Surface Finishes
As-Turned (Natural)
Standard finish produced by the turning tool itself, Ra 0.8-3.2μm depending on feed rate and insert nose radius. The most economical option – ideal for internal parts, bearing surfaces and any feature that will be further processed.
Centerless Grinding
Precision grinding of cylindrical surfaces to Ra ≤0.4μm with roundness ≤0.003mm and tight diameter control. The standard finish for bearing journals, hydraulic cylinder rods and pump shafts where roundness directly affects performance.
Polishing (Satin / Mirror)
Mechanical polishing of turned surfaces for decorative or hygienic applications. Satin: uniform directional grain Ra 0.4-0.8μm. Mirror: Ra ≤0.1μm, suitable for food-contact parts, medical components and display hardware.
Black Oxide
Alkaline chemical conversion coating for steel that produces a matte black finish with mild corrosion resistance and minimal dimensional change (1-2μm). Common on shafts, tooling components and military hardware where gloss is undesirable.
Passivation
Citric or nitric acid passivation for stainless steel turned parts, removing free iron and restoring the protective chromium oxide layer. No dimensional change – the standard post-machining treatment for stainless components.
Anodizing & Plating
Type II/III anodizing for aluminum turned parts (5-25μm / 25-150μm, color options). Zinc, nickel or chrome plating available for steel and brass parts where corrosion resistance and appearance are required.
Design for Manufacturing (DFM)
- Limit length-to-diameter ratio to 6:1 for chuck turning; longer slender shafts require a steady rest or turning between centers to control deflection and chatter
- Provide center holes (60° included angle) on shaft ends that will be machined between centers – this is the most accurate setup for concentric diameters
- Add thread relief grooves and undercuts at thread ends to allow full thread depth and prevent feather-edge burrs that interfere with mating parts
- Specify generous corner radii (R0.2 minimum) on external shoulders – sharp 90° shoulders leave burrs and stress tool tips
- Use standard bar or billet sizes to minimize material removal; machining from Ø50mm bar for a Ø20mm part wastes cycle time and material
- Prefer free-cutting grades (SUS303, C3604 brass, POM) when the design allows – they cut faster, chip better and finish smoother at lower cost
- Group cross features (flats, keyways, cross-holes) into one face where possible so mill-turn live tooling can complete them in a single setup
- Apply tight tolerances only to functional diameters; general ±0.1mm on non-critical features cuts both machining time and inspection cost
- Avoid interrupted cuts and deep narrow grooves where possible – they cause vibration, poor finish and tool breakage; consider split designs for complex profiles
- Send 2D drawings with critical dimensions marked, or STEP models; we return a free DFM review noting turning strategy, stock size and cost drivers before production
Tooling & Capacity
| Type | Lead Time | Suitable For |
|---|---|---|
| CNC Lathe (2-axis, chuck + bar feeder) | 3-5 days prototype / 7-10 days production | Shafts, bushings, pins, rings, threaded parts and all rotational geometry. Bar feeder automation drives down per-piece cost on volume runs |
| CNC Turning Center (Live Tooling / Mill-Turn) | 5-10 days depending on complexity | Parts needing milling, drilling or cross-features combined with turning – keyways, flats, hexagons, eccentric bores – completed in one setup for best concentricity |
| Swiss-Type Automatic Lathe | 7-14 days depending on complexity | Small precision parts Ø3-32mm with high feature density: connector pins, medical shafts, watch and instrument components with sub-micron concentricity |
| Production Fixtures & Soft Jaws | 1-2 weeks for repeat production tooling | Volume runs of 1,000-100,000 pieces requiring consistent clamping, quick load/unload and stable quality from first to last part |
Quality Assurance
- Incoming material verification – alloy, diameter and surface condition checked and recorded before any bar is loaded
- First Article Inspection with full dimensional report (CMM + hand gauges) on the first machined part of every batch
- Concentricity and runout measurement on all shaft-type parts using V-blocks and dial indicators
- Thread verification with go/no-go ring and plug gauges; pitch diameter measured on critical threads
- Surface roughness verification by profilometer on bearing journals, seal surfaces and cosmetic diameters
- In-process measurement at critical stages so a drifting dimension is caught before multiple parts are produced
- Roundness and straightness checks on ground shafts; cylindricity verified on precision journals
- Visual inspection for burrs, chatter marks, tool dwell and surface defects against agreed acceptance samples
- Final dimensional report with measured values shipped with every batch; traveler and inspection records retained
- Calibrated instruments only: micrometers (0.001mm), indicators, bore gauges, thread gauges – all on a fixed calibration schedule
Applications
- Automotive and motorsport: shafts, axles, spacers, valve stems, sensor housings, throttle components, fastener hardware
- Hydraulics and pneumatics: cylinder rods, piston guides, valve spools, manifold plugs, fitting bodies
- Electronics and connectors: turned connector bodies, insulating bushings, RF components, switchgear parts
- Food and beverage equipment: stainless shafts, augers, valve components, hygienic fittings
- Medical and laboratory: instrument shafts, fitting components, device hardware, diagnostic equipment parts
- Industrial machinery: pulleys, idlers, bushings, sleeves, pump components, gear blanks
- Optics and photonics: lens mounts, focus rings, rotation stages, precision bores for optical assemblies
- Consumer and appliance: decorative hardware, knobs, threaded studs, hinge pins, replacement repair parts
Why Choose FHY Precision
Turning specialists: our machinists cut rotational geometry daily – the feeds, speeds, insert geometries and coolant strategies are tuned per material, not learned on your part
Mill-turn under one roof: live-tooling turning centers add cross-holes, keyways, flats and hexagons in the same setup, eliminating second-operation tolerance stack-up
True concentricity: ≤0.005mm between centers on precision work – verified by indicator, not assumed from machine accuracy
Bar automation economics: bar-feed production removes per-piece loading labor, making volume turned parts price-competitive against stamping and screw machining
Wide material range: from POM insulators to PEEK and titanium, with material-specific tooling libraries and parameters already established
MOQ 1 piece: prototype turned parts carry no minimum – a single shaft is machined with the same care as a 10,000-piece run
Free DFM review: we flag slender ratios, relief grooves, stock optimization and tolerance hot spots before cutting metal
Full traceability: material lot, program revision and inspection records retained for every batch; dimensional report ships with the parts
FAQ
1. What is the difference between CNC turning and CNC milling?
Turning rotates the workpiece while the cutting tool stays stationary – it produces round geometry (shafts, bushings, rings, threads). milling rotates the tool and produces flat or prismatic geometry. Many real parts need both; that is why we invest in mill-turn centers that combine both operations in one setup. If your part is fundamentally rotational, turning is faster and more accurate.
2. What tolerances can you hold on turned parts?
Standard dimensional tolerance is ±0.02mm. On critical diameters we consistently achieve ±0.005mm using in-process measurement and finishing passes. Concentricity between centers is held to ≤0.005mm. Ground surfaces reach Ra ≤0.4μm with roundness ≤0.003mm. General tolerance standards (ISO 2768-m) apply to unspecified dimensions.
3. What is your MOQ for CNC turning?
MOQ is 1 piece. A single prototype shaft is machined with the same process controls as production. For volume runs above 500 pieces, bar-feed automation and production fixtures reduce per-piece cost significantly – but there is no minimum to start.
4. Can you turn parts with cross-holes, flats or keyways?
Yes – on our live-tooling turning centers (mill-turn). Cross-drilled holes, milled flats, keyways, hexagons and even eccentric features are completed while the part is held in the main spindle, so the relationship between turned and milled features is far more accurate than two separate setups. For very complex milling work we also run dedicated 3-axis and 4-axis mills.
5. Which materials do you turn, and which is cheapest?
We turn carbon steel (45#), stainless (303/304/316L), aluminum (6061/7075/5052), brass (H62/C3604), copper, POM, PA66, PC, PEEK and titanium. Aluminum and free-cutting brass (C3604) are typically the most economical due to high cutting speeds and long tool life. Stainless 316L and titanium cost more because of slower speeds, tool wear and coolant requirements – we will recommend a substitute when the design allows.
6. What is concentricity and why does it matter?
Concentricity is how closely multiple diameters share a common axis. Poor concentricity causes vibration, uneven bearing wear, seal leakage and runout in rotating assemblies. We hold ≤0.005mm between centers and verify every shaft-type part with a dial indicator. Parts machined entirely in one turning setup are inherently more concentric than parts moved between machines.
7. When do parts need centerless grinding instead of turning?
Turning alone reaches Ra 0.8-3.2μm. When your drawing calls for Ra ≤0.4μm, tight diameter tolerance (±0.005mm) or roundness ≤0.003mm – typical on bearing journals, hydraulic rods and pump shafts – a centerless grinding pass after turning is the standard route. We can turn and grind in-house, keeping both operations under one quality system.
8. How do you control burrs and edge quality on turned parts?
Turning leaves a fine burr at every exit edge. We control it at the source with relief grooves, proper insert nose radius and chamfer passes, then finish with deburring, tumbling or brushing depending on the part. Sharp internal corners in grooves are avoided in DFM review because they trap burrs that cannot be reached.
9. What threads can you machine?
M3 to M60 metric, plus UNC/UNF, BSP and NPT, cut by single-point threading (best concentricity and finish), tapping or thread milling. Internal threads up to M60 in chuck work. Thread relief grooves are added automatically when the design allows, so threads run out clean instead of ending in a feather edge.
10. How is pricing calculated for turned parts?
Price = material + machine time (setup + cycle) + finishing + inspection. The big cost drivers are part length-to-diameter ratio (slender parts need steady rests and light passes), tolerance class, material machinability and quantity. Volume runs amortize setup over many pieces; a single prototype carries the full setup. We provide itemized quotes within 24 hours.
11. Can you machine from our supplied material or bar?
Yes. We regularly machine customer-supplied material – bring your own certified bar or billet and we will treat it with full traceability. We verify diameter, alloy and surface condition on receipt and flag any issue before cutting. If sourcing is easier, we buy from established mills and include material documentation with shipment.
12. Do you work from 2D drawings only?
Yes. Many customers send PDF or DWG drawings with critical dimensions marked – our programmers interpret them directly. For prototypes without any CAD, we can also machine from a physical sample by CMM-scanning it and building a model. STEP or IGES files are always preferred for complex geometry, but 2D is not a blocker.
13. What lead times should I plan for turned parts?
Prototypes (1-10 pieces): 3-5 business days for standard lathe work, 5-10 days for mill-turn or Swiss work. Production runs: 7-15 business days depending on quantity, plus 3-5 days for plating, grinding or other finishing. All dates are confirmed in writing with the quotation.
14. What length-to-diameter ratio can you turn without chatter?
As a working guideline, keep the length-to-diameter ratio below 10:1 on a conventional lathe with standard tooling. Beyond roughly 3:1 we add support – tailstock center, steady rest, or Swiss-type guide bushing – because an unsupported slender shaft deflects under cutting force and produces taper, chatter marks and out-of-tolerance diameters. If your part is a long slender shaft, tell us the L:D ratio at quoting so we select the right machine and support strategy instead of discovering deflection at first article.
15. When is a bar feeder worth it?
Usually above roughly 1,000 pieces. Below that, the bar feeder setup time and the remnant loss on short bars can eat the cycle-time saving – for a 200-piece order the honest answer is often chucking. The break-even moves lower if the part needs back working that a sub-spindle can complete in cycle. Ask us for cycle time with and without bar feed before you decide; the right answer depends on your quantity and part geometry, not on a rule of thumb.
16. What surface finish can turning achieve without grinding?
With a sharp insert and correct feeds and speeds, turning reaches Ra 0.8-1.6μm as a working range, and Ra 0.2-0.8μm on a fine finishing pass in aluminum and free-machining steels. Below that, grinding or superfinishing is the practical route. For most functional surfaces – shafts, bores, sealing diameters – turning alone is sufficient. Where the drawing calls for Ra 0.4μm or tighter with tight roundness, we plan a centerless grinding step after turning and quote the combined route.