CNC Milling 42CrMo Steel is part of VT machining's grade-specific capability. 42CrMo Steel is strong, economical and widely available, and we combine controlled machining with material-aware setup to produce parts that meet your specification.
CNC Milling Capability for 42CrMo Steel
- Carbon/low-alloy grades
- Economical & weldable
- Tolerance to ±0.02 mm
- Hardenable by heat treat
42CrMo 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.
Machining 42CrMo Steel with CNC Milling
42CrMo Steel behaves predictably under CNC Milling once parameters are dialled in: machinability is good to excellent depending on carbon content; free-machining grades cut cleanly, and we tune the operation accordingly.
We hold reference parameters for this grade, so repeat orders of 42CrMo Steel run consistently from one batch to the next.
Achievable Tolerances for CNC Milling 42CrMo Steel
| Feature | Standard | Precision |
|---|---|---|
| Linear dimension (< 100 mm) | ±0.05 mm | ±0.010 mm |
| Linear dimension (100–300 mm) | ±0.10 mm | ±0.025 mm |
| Hole diameter (reamed) | H9 | H7 |
| True position of hole pattern | ±0.10 mm | ±0.025 mm |
| Flatness over 100 mm | 0.05 mm | 0.015 mm |
| Perpendicularity | 0.10 mm | 0.020 mm |
| Surface finish, as machined | 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.
Secondary Operations & Finishing
Finished 42CrMo 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 Milling 42CrMo Steel
We are happy to suggest design tweaks that improve manufacturability. Generous internal radii, sensible pocket depth-to-width ratios and avoiding very thin unsupported walls all reduce cost and improve accuracy in 42CrMo Steel. If you send your model early, we will return practical DFM feedback before you commit to production.
CNC Milling Tolerances & Surface Finish
For CNC Milling, dimensional and positional tolerances around ±0.01 mm are routine, tightening toward ±0.005 mm on precision setups. Surface finish on machined faces typically falls in the Ra 0.4–1.6 µm range depending on tooling and pass strategy.
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.
CNC Milling 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 42CrMo Steel part to print. Inspection reports, material certificates and first-article documentation can be supplied on request.
Why 42CrMo Steel?
42CrMo Steel is chosen when a part needs what this grade offers — it is strong, economical and widely available. We confirm the grade and any temper or heat-treat condition with you before machining.
Applications of CNC Milling 42CrMo Steel
Customers order CNC Milling 42CrMo 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 Milling 42CrMo 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 42CrMo 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 Milling 42CrMo 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 42CrMo 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.
42CrMo Steel in Other Processes
Related
Send the drawing, the 42CrMo Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
How clean are the edges produced by CNC Milling on 42CrMo Steel?
Machined 42CrMo Steel edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
Which industries use CNC Milling 42CrMo Steel parts?
CNC Milling 42CrMo Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 42CrMo Steel components are required.
What material thickness or size range suits CNC Milling 42CrMo Steel?
We machine 42CrMo Steel across a broad size range; share your part envelope for confirmation.
Does CNC Milling 42CrMo Steel require dedicated tooling?
Most 42CrMo Steel machining work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What is CNC Milling 42CrMo Steel and how is it done?
CNC Milling 42CrMo Steel refers to multi-axis milling cutters remove material to produce prismatic features, pockets, slots and contoured 3D surfaces. Applied to 42CrMo Steel — strong, economical and widely available — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.