VT machining specialises in CNC Thread Grinding 309 Stainless Steel. Because 309 Stainless Steel is corrosion resistant, strong and hygienic, and its machinability is moderate; work-hardens, so positive-rake tooling and steady feeds are used to avoid glazing, we plan each job around the grade to protect accuracy and surface quality.
CNC Thread Grinding Capability for 309 Stainless Steel
- Austenitic/martensitic grades
- Corrosion resistant
- Tolerance to ±0.01 mm
- Typical hardness 70–200 HB (annealed)
309 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 309 Stainless Steel with CNC Thread Grinding
309 Stainless Steel behaves predictably under CNC Thread Grinding 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 309 Stainless Steel run consistently from one batch to the next.
Achievable Tolerances for CNC Thread Grinding 309 Stainless Steel
| Feature | Standard | Precision |
|---|---|---|
| Size (OD, ID, thickness) | ±0.005 mm | ±0.002 mm |
| Flatness over 100 mm | 0.010 mm | 0.003 mm |
| Parallelism | 0.010 mm | 0.003 mm |
| Roundness | 0.005 mm | 0.002 mm |
| Squareness | 0.010 mm | 0.005 mm |
| Surface finish | Ra 0.4 µm | Ra 0.1 µm |
| Workpiece hardness | up to 62 HRC | up to 65 HRC |
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.
CNC Thread Grinding 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 309 Stainless Steel part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Secondary Operations & Finishing
Finished 309 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.
Design Tips for CNC Thread Grinding 309 Stainless Steel
We are happy to suggest design tweaks that improve manufacturability. Allowing adequate grind stock, specifying realistic flatness over the true datum, and relieving corners help us hit tight tolerances on 309 Stainless Steel efficiently. If you send your model early, we will return practical DFM feedback before you commit to production.
Why 309 Stainless Steel?
309 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 Thread Grinding Tolerances & Surface Finish
Ground 309 Stainless Steel reaches single-micron tolerances on size, flatness and parallelism, with surface finishes down to Ra 0.1–0.4 µm — and a near-mirror finish on suitable alloys.
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.
Applications of CNC Thread Grinding 309 Stainless Steel
Customers order CNC Thread Grinding 309 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 Thread Grinding 309 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 309 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 Thread Grinding 309 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 309 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.
309 Stainless Steel in Other Processes
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Send the drawing, the 309 Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Does CNC Thread Grinding 309 Stainless Steel require dedicated tooling?
Most 309 Stainless Steel grinding work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What is the typical lead time and minimum order for CNC Thread Grinding 309 Stainless Steel?
CNC Thread Grinding prototypes for 309 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.
Why is 309 Stainless Steel a good choice for CNC Thread Grinding?
309 Stainless Steel is corrosion resistant, strong and hygienic, which makes it well suited to CNC Thread Grinding. We tune the process to the alloy so the finished 309 Stainless Steel grinding part meets your dimensional and functional requirements.
Which industries use CNC Thread Grinding 309 Stainless Steel parts?
CNC Thread Grinding 309 Stainless Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 309 Stainless Steel components are required.
What is CNC Thread Grinding 309 Stainless Steel and how is it done?
CNC Thread Grinding 309 Stainless Steel refers to thread grinding produces precise, high-finish threads on hardened parts and lead screws. Applied to 309 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.