CNC Thread Grinding Alloy Steel is a core capability at VT machining. We combine controlled grinding with material-aware setup for Alloy Steel — an alloy that is high strength and hardenability for demanding parts — to produce parts that meet your specification first time.

CNC Thread Grinding Capability for Alloy Steel
- Pitch accuracy to grade 3
- Hardened-part threading
- Lead screws & gauges
- Fine surface finish
Alloy Steel Material Data
| Density | 7.85 g/cm³ |
|---|---|
| Tensile strength | 655–1020 MPa |
| Yield strength (0.2%) | 415–900 MPa |
| Hardness | 197–302 HB |
| Melting point | 1416 °C |
| Thermal conductivity | 42.6 W/m·K |
| Thermal expansion | 12.3 ×10⁻⁶/K |
| Electrical conductivity | 8% |
| Machinability (C36000 = 100%) | 65% (annealed) |
| Grades we run | 4140, 4340, 8620, 20CrMnTi, 42CrMo4, 20MnCr5 |
Published typical values for 4140 (Q&T). Other grades in the family differ — the certificate supplied with your order carries the actual heat-lot figures.
Heat treatment moves the part. Anything held tighter than ±0.02 mm is machined soft, hardened, then ground or hard-turned to final size.
How CNC Thread Grinding Alloy Steel Works
An abrasive wheel removes a fine, controlled layer from the Alloy Steel part. Wheel specification, dressing interval, infeed and coolant are matched to the alloy's hardness so the surface is not burned or left with residual stress.
Every job begins from your CAD model or 2D drawing. Fixturing and tool paths are planned so the most critical dimensions are produced in the most rigid, repeatable setup. Critical dimensions are checked on the first part and monitored through the run.
Achievable Tolerances for CNC Thread Grinding Alloy 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.
Working with Alloy Steel
Alloy Steel offers a useful combination of properties: it is high strength and hardenability for demanding parts. Those characteristics shape how we approach grinding — from tool and parameter selection to work-holding and coolant.
If your application is sensitive to alloy condition, we agree the specification in writing and document it. Stock is sourced from reputable suppliers so what you order is what you receive.
CNC Thread Grinding Quality & Inspection
Consistent quality comes from disciplined process control. Critical dimensions on Alloy Steel parts are checked in-process and verified at final inspection using calibrated instruments and, where required, CMM measurement. Full documentation — dimensional reports, mill certs, FAIR — is available when your programme needs it.
Design Tips for CNC Thread Grinding Alloy Steel
A few design choices make a real difference to cost and quality. Allowing adequate grind stock, specifying realistic flatness over the true datum, and relieving corners help us hit tight tolerances on Alloy Steel efficiently. If you send your model early, we will return practical DFM feedback before you commit to production.
CNC Thread Grinding Tolerances & Surface Finish
Ground Alloy 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.
Secondary Operations & Finishing
We complete Alloy Steel components with the secondary steps your drawing calls for. We arrange heat treatment, surface treatment, marking and assembly as needed. Tell us the final spec and we will plan the full route so parts arrive ready to use.
Applications of CNC Thread Grinding Alloy Steel
CNC Thread Grinding of Alloy Steel supports parts across aerospace, medical, automotive, electronics, semiconductor, energy and general industrial sectors. We scale from one-off prototypes to ongoing production while holding the same quality.
How to Order CNC Thread Grinding Alloy Steel
Ordering Alloy Steel parts is straightforward. Provide the drawing, material, quantity and any certification needs. Our engineers reply — in English — with feasibility, pricing and a realistic lead time, usually within one business day.
Parts We Have Run in Alloy Steel
Three representative CNC Thread Grinding Alloy 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.
Mould insert
- Material
- Alloy Steel
- Size
- 80 × 60 × 25 mm
- Key callouts
- Flatness 0.003 mm, squareness 0.005 mm
- Batch
- 90 pcs
Surface ground on all six faces so the insert seats without shimming.
Ceramic-coated shaft journal
- Material
- Alloy Steel
- Size
- Ø45 × 180 mm
- Key callouts
- OD ±0.003 mm, roundness 0.002 mm, Ra 0.2 µm
- Batch
- 150 pcs
Ground after coating; the coating is never the final dimension.
Lapping plate
- Material
- Alloy Steel
- Size
- 300 × 300 × 30 mm
- Key callouts
- Flatness 0.005 mm over the full face
- Batch
- 20 pcs
Ground, stress-relieved, ground again — one pass will not hold flatness on this area.
Finishing Options for Alloy Steel
| Finish | Thickness / effect | Why it gets specified |
|---|---|---|
| Through hardening | — | 30–55 HRC, ground afterwards for tight sizes |
| Case hardening (carburise) | 0.3–1.2 mm case | 58–62 HRC surface, tough core |
| Nitride | 0.1–0.5 mm | 900–1100 HV, minimal distortion |
| Black oxide | 1–2 µm | Cosmetic + light corrosion protection |
| Zinc / nickel plate | 5–25 µm | Corrosion protection |
| 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 Alloy 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 Alloy 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 Thread Grinding
Other Processes for Alloy Steel
Send the drawing, the Alloy 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 tolerances can you hold for CNC Thread Grinding Alloy Steel?
Achievable tolerances for Alloy Steel grinding depend on the alloy, geometry and feature size. Grinding routinely holds single-micron tolerances on diameter, flatness and parallelism. Exact figures are confirmed against your drawing callouts.
How clean are the edges produced by CNC Thread Grinding on Alloy Steel?
Machined Alloy Steel edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
What material thickness or size range suits CNC Thread Grinding Alloy Steel?
We machine Alloy Steel across a broad size range; share your part envelope for confirmation.
Why is Alloy Steel a good choice for CNC Thread Grinding?
Alloy Steel is high strength and hardenability for demanding parts, which makes it well suited to CNC Thread Grinding. We tune the process to the alloy so the finished Alloy Steel grinding part meets your dimensional and functional requirements.
Can VT machining make custom Alloy Steel parts to my drawing?
Yes. Alloy Steel Alloy Steel grinding 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.
Which industries use CNC Thread Grinding Alloy Steel parts?
CNC Thread Grinding Alloy Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise Alloy Steel components are required.
