VT machining provides CNC Polishing Steel for customers who need accurate, repeatable Steel components. Because Steel is strong, economical, widely available carbon/alloy grades, we adapt the process to suit — controlling the variables that matter for this alloy.
CNC Polishing Capability for Steel
- Mirror finish capable
- Ra to 0.05 µm
- Cosmetic & sealing faces
- Multi-stage abrasives
Steel Material Data
| Density | 7.85 g/cm³ |
|---|---|
| Tensile strength | 585 MPa |
| Yield strength (0.2%) | 450 MPa |
| Hardness | 170 HB |
| Melting point | 1420–1460 °C |
| Thermal conductivity | 51.9 W/m·K |
| Thermal expansion | 11.5 ×10⁻⁶/K |
| Electrical conductivity | 9% |
| Machinability (C36000 = 100%) | 57% |
| Grades we run | 1018, 1045, 1215, A36, S45C, St37, 4140 (see alloy steel) |
Published typical values for 1045. Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
Rust. Bare steel flash-rusts within hours in a humid container, so parts are oiled or passivated before packing unless you specify otherwise.
How CNC Polishing Steel Works
Abrasive media or tooling refine the Steel surface in controlled stages, removing the previous step's marks until the target roughness and edge condition are reached.
Programming is driven directly by your 3D model or print. Work-holding, tool selection and the cutting strategy are planned around the critical features and the material before the first chip is cut. First-off inspection confirms the process is centred before production continues.
Achievable Tolerances for CNC Polishing Steel
| Feature | Standard | Precision |
|---|---|---|
| Surface roughness | Ra 0.8 µm | Ra 0.05 µm |
| Edge break | 0.1–0.3 mm | 0.05 ±0.02 mm |
| Material removed | 0.02 mm | 0.005 mm |
| Bore roundness after honing | 0.005 mm | 0.002 mm |
| Cross-hatch angle | 45° ±10° | 45° ±5° |
| Cosmetic grade | uniform satin | mirror, no visible lines |
| Masking of datum faces | on request | standard |
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 Polishing 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 Steel part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Secondary Operations & Finishing
Finished 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.
CNC Polishing Tolerances & Surface Finish
Finishing brings Steel to a defined roughness target — from a uniform satin to Ra values as low as 0.05 µm — with controlled, repeatable edge breaks.
Exact achievable figures depend on the alloy, the feature size and the part geometry. Tell us which dimensions are critical and we will advise feasibility up front.
Design Tips for CNC Polishing Steel
We are happy to suggest design tweaks that improve manufacturability. Telling us the target Ra, the cosmetic faces and any masking needs lets us finish Steel efficiently without over-processing. If you send your model early, we will return practical DFM feedback before you commit to production.
Working with Steel
As a material, Steel is strong, economical, widely available carbon/alloy grades. Our setup reflects the alloy's machinability so the finished part is accurate and free of avoidable defects.
We verify the exact grade and condition before machining, and traceable mill certs are available on request. We can work to your nominated material source or specification when required.
Applications of CNC Polishing Steel
Customers order CNC Polishing 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 Polishing 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.
Parts We Have Run in Steel
Three representative CNC Polishing Steel jobs, with the callouts that actually drove the process plan. Yours will differ — these are here so you can judge whether your part is in our range before you spend time on an RFQ.
Hydraulic bore
- Material
- Steel
- Size
- Ø32 × 200 mm
- Key callouts
- Ra 0.4 µm cross-hatch 45°, roundness 0.003 mm
- Batch
- 600 pcs
Honed in three stages; the cross-hatch is what holds the oil film.
Passivated stainless fitting
- Material
- Steel
- Size
- Ø18 × 40 mm
- Key callouts
- ASTM A967 citric passivation, no free iron
- Batch
- 5,000 pcs
Passivated after all machining, then tested with a copper sulphate check.
Mirror-polished insert
- Material
- Steel
- Size
- 80 × 50 mm cavity
- Key callouts
- Ra 0.05 µm, SPI A2
- Batch
- 60 pcs
Polished in five abrasive stages; skipping one leaves scratches the next cannot remove.
Finishing Options for Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Black oxide | 1–2 µm | Mild corrosion resistance, no dimensional change |
| Zinc plate + clear/yellow | 5–12 µm | ASTM B633, general corrosion protection |
| Nickel plate (electroless) | 10–25 µm | Uniform in bores, 500 HV after bake |
| Phosphate | 5–10 µm | Paint key, mild lubricity |
| Powder coat | 60–120 µm | RAL colours |
| 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 Polishing 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 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.
Other Metals for CNC Polishing
Other Processes for Steel
Send the drawing, the Steel grade and the quantity. You get pricing, lead time and any DFM notes back — usually within one business day.
Request a QuoteFrequently Asked Questions
What surface finish is achievable on Steel with CNC Polishing?
Our finishing processes refine Steel surfaces to Ra values as low as 0.05 µm for cosmetic or sealing faces.
Why is Steel a good choice for CNC Polishing?
Steel is strong, economical, widely available carbon/alloy grades, which makes it well suited to CNC Polishing. We tune the process to the alloy so the finished Steel finishing part meets your dimensional and functional requirements.
What tolerances can you hold for CNC Polishing Steel?
Achievable tolerances for Steel finishing depend on the alloy, geometry and feature size. We hold tight, repeatable tolerances appropriate to the feature and material. Exact figures are confirmed against your drawing callouts.
How clean are the edges produced by CNC Polishing on Steel?
Our deburring leaves Steel with a consistent, controlled edge break and burr-free surfaces.
Can VT machining make custom Steel parts to my drawing?
Yes. Steel Steel finishing is made to order from your CAD/2D drawing. Share your geometry, material grade, tolerance and quantity and we will confirm feasibility, lead time and pricing.