CNC Turning 309S Stainless Steel is part of VT machining's grade-specific capability. 309S Stainless Steel is corrosion resistant, strong and hygienic, and we combine controlled turning with material-aware setup to produce parts that meet your specification.
CNC Turning Capability for 309S Stainless Steel
- Austenitic/martensitic grades
- Corrosion resistant
- Tolerance to ±0.01 mm
- Typical hardness 70–200 HB (annealed)
309S Stainless Steel Material Data
| Density | 8.00 g/cm³ |
|---|---|
| Tensile strength | 515 MPa |
| Yield strength (0.2%) | 205 MPa |
| Hardness | 170 HB |
| Melting point | 1400–1450 °C |
| Thermal conductivity | 16.2 W/m·K |
| Thermal expansion | 17.3 ×10⁻⁶/K |
| Electrical conductivity | 2.4% |
| Machinability (C36000 = 100%) | 45% |
| Grades we run | 303, 304/304L, 316/316L, 321, 410, 416, 420, 17-4PH, 2205 duplex |
Published typical values for 304. Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
It work-hardens the moment a tool dwells. Constant feed and positive-rake tooling; a rubbing pass leaves a glazed skin the next tool cannot get through.
Machining 309S Stainless Steel with CNC Turning
309S Stainless Steel behaves predictably under CNC Turning once parameters are dialled in: machinability is moderate; work-hardens, so positive-rake tooling and steady feeds are used to avoid glazing, and we tune the operation accordingly.
We hold reference parameters for this grade, so repeat orders of 309S Stainless Steel run consistently from one batch to the next.
Achievable Tolerances for CNC Turning 309S Stainless Steel
| Feature | Standard | Precision |
|---|---|---|
| Outside diameter | ±0.05 mm | ±0.005 mm |
| Bore diameter | H9 | H6 |
| Length / shoulder position | ±0.10 mm | ±0.020 mm |
| Concentricity OD to ID | 0.05 mm TIR | 0.010 mm TIR |
| Roundness | 0.02 mm | 0.005 mm |
| Thread class | 6g / 2A | 4h / 3A |
| Surface finish, as turned | Ra 1.6 µm | Ra 0.4 µm |
Standard is what a normal quotation assumes. Precision is available on nominated features and is priced separately, because it needs extra setups, in-process gauging and CMM verification. Call out only the features that need it — blanket-tightening a drawing is the single most common reason a quote comes back expensive.
Design Tips for CNC Turning 309S Stainless Steel
We are happy to suggest design tweaks that improve manufacturability. Consistent diameters, standard thread forms and avoiding extremely long, slender features help 309S Stainless Steel turned parts stay concentric and economical. If you send your model early, we will return practical DFM feedback before you commit to production.
CNC Turning Quality & Inspection
We control quality throughout the process, not just at the end. In-process checks plus final inspection — including CMM where specified — keep every 309S Stainless Steel part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Why 309S Stainless Steel?
309S Stainless Steel is chosen when a part needs what this grade offers — it is corrosion resistant, strong and hygienic. We confirm the grade and any temper or heat-treat condition with you before machining.
CNC Turning Tolerances & Surface Finish
Turned 309S Stainless Steel holds diameter tolerances to about ±0.005 mm with concentricity within 0.01 mm and good roundness. Turned finishes of Ra 0.4–0.8 µm are achievable with finishing passes and sharp tooling.
Final tolerances are governed by the material's behaviour, wall thickness and overall stiffness. We give honest DFM feedback if a callout would be costly or better achieved another way.
Secondary Operations & Finishing
Finished 309S Stainless Steel parts can move straight into secondary operations under one roof. Typical add-ons are deburring, passivation, anodising, plating, blasting, polishing and laser marking. We coordinate the whole chain so you receive complete, inspection-ready parts.
Applications of CNC Turning 309S Stainless Steel
Customers order CNC Turning 309S Stainless Steel components for everything from instrumentation to structural and functional assemblies. Whether you need a single prototype or recurring production volume, the same process discipline applies.
How to Order CNC Turning 309S Stainless Steel
Getting a quote is simple. Share your model, the material grade, your quantity and target tolerances. You receive a clear quotation with lead time and honest manufacturability feedback.
Finishing Options for 309S Stainless Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Citric passivation | — | ASTM A967 / AMS 2700, removes free iron |
| Electropolish | 5–25 µm removed | Ra improves by roughly half, hygienic surface |
| Brushed / grained | Ra 0.4–1.6 µm | No. 4 finish, directional |
| PVD coating | 2–5 µm | TiN, TiCN for wear surfaces |
| Deburr / edge break | 0.05–0.3 mm | All parts unless the drawing says otherwise |
| Bead blast | Ra 1.6–3.2 µm | Uniform matt finish, hides tool marks |
| Laser marking | — | Part number, lot code, data matrix |
No drawing yet? Build one in the browser.
Set the metal, dimensions and features, watch the 3D model update as you type, then switch to the 2D sheet to add dimensions and tolerances. Download it or send it straight to us with your RFQ.
What We Need to Quote CNC Turning 309S Stainless Steel
- GeometrySTEP or IGES for the 3D model, plus a PDF drawing if you have tolerance callouts. A dimensioned sketch is enough to start.
- MaterialThe exact 309S Stainless Steel grade and condition — temper, heat-treat state or hardness. If you are not sure, tell us the function and we will suggest one.
- QuantityPrototype count and the expected annual volume. Both change how the part is made and therefore what it costs.
- TolerancesWhich features are critical. Everything else runs to our standard tolerance, which is what keeps the price sensible.
- FinishSurface treatment, cosmetic requirements, and any faces that must be masked.
- DocumentsWhether you need a material certificate, dimensional report, FAIR or PPAP with the shipment.
Missing something from the list is not a problem — send what you have. We will come back with the specific questions rather than a generic form.
309S Stainless Steel in Other Processes
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Send the drawing, the 309S Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What is the typical lead time and minimum order for CNC Turning 309S Stainless Steel?
CNC Turning prototypes for 309S Stainless Steel can be produced quickly and scaled to series production. Send your drawing and quantity and we will advise lead time and any minimum order.
What material thickness or size range suits CNC Turning 309S Stainless Steel?
Turned 309S Stainless Steel parts are produced from bar or chuck stock across a wide diameter range.
What is CNC Turning 309S Stainless Steel and how is it done?
CNC Turning 309S Stainless Steel refers to cNC turning rotates the workpiece against a single-point tool to produce cylindrical features, threads and grooves. Applied to 309S Stainless Steel — corrosion resistant, strong and hygienic — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
Why is 309S Stainless Steel a good choice for CNC Turning?
309S Stainless Steel is corrosion resistant, strong and hygienic, which makes it well suited to CNC Turning. We tune the process to the alloy so the finished 309S Stainless Steel turning part meets your dimensional and functional requirements.
Which industries use CNC Turning 309S Stainless Steel parts?
CNC Turning 309S Stainless Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 309S Stainless Steel components are required.