CNC Gear Hobbing 4340 Alloy Steel from VT machining delivers precision 4340 Alloy Steel parts made to your exact drawing. Gear hobbing generates gear teeth with a rotating hob synchronized to the workpiece, with parameters tuned to 4340 Alloy Steel, which is high-strength and hardenable.
CNC Gear Hobbing Capability for 4340 Alloy Steel
- Cr-Mo / Ni-Cr-Mo grades
- High strength & hardenability
- Tolerance to ±0.01 mm
- Heat-treatable to 30–55 HRC
4340 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.
Machining 4340 Alloy Steel with CNC Gear Hobbing
The machinability of 4340 Alloy Steel is good in annealed condition; machined soft then heat-treated to final hardness. For CNC Gear Hobbing we select tooling, feeds, speeds and coolant to match, keeping the 4340 Alloy Steel workpiece stable and the result accurate.
Because we machine 4340 Alloy Steel regularly, proven settings shorten setup and keep quality repeatable across reorders.
Achievable Tolerances for CNC Gear Hobbing 4340 Alloy Steel
| Feature | Standard | Precision |
|---|---|---|
| Accuracy class | DIN 8 / AGMA 10 | DIN 6 / AGMA 12 |
| Profile deviation | 0.020 mm | 0.008 mm |
| Lead deviation | 0.020 mm | 0.008 mm |
| Pitch deviation (cumulative) | 0.040 mm | 0.015 mm |
| Runout | 0.030 mm | 0.010 mm |
| Tooth surface finish | Ra 1.6 µm | Ra 0.4 µm (ground) |
| Module range | m0.5–m8 | m1–m6 |
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 Gear Hobbing 4340 Alloy Steel
A few design choices make a real difference to cost and quality. Providing complete gear data (module, pressure angle, profile shift, quality class) lets us produce 4340 Alloy Steel gears right the first time. If you send your model early, we will return practical DFM feedback before you commit to production.
Secondary Operations & Finishing
We complete 4340 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.
CNC Gear Hobbing Tolerances & Surface Finish
Gear features are produced to a specified DIN/AGMA accuracy class, with profile and lead controlled for quiet, durable running under load.
The tightest tolerances are reserved for the features your drawing flags as critical. Share your tolerance scheme and we will confirm what is realistic before quoting.
CNC Gear Hobbing Quality & Inspection
Consistent quality comes from disciplined process control. Critical dimensions on 4340 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.
Why 4340 Alloy Steel?
Specifying 4340 Alloy Steel for CNC Gear Hobbing 4340 Alloy Steel is usually about its properties: high-strength and hardenable. Tell us the condition you need and we machine to it.
Applications of CNC Gear Hobbing 4340 Alloy Steel
CNC Gear Hobbing of 4340 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 Gear Hobbing 4340 Alloy Steel
Ordering 4340 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.
Finishing Options for 4340 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 Gear Hobbing 4340 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 4340 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.
4340 Alloy Steel in Other Processes
Related
Send the drawing, the 4340 Alloy Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
Does CNC Gear Hobbing 4340 Alloy Steel require dedicated tooling?
Most 4340 Alloy Steel gear cutting work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
How clean are the edges produced by CNC Gear Hobbing on 4340 Alloy Steel?
Machined 4340 Alloy Steel edges are clean and to specification; edge-break or deburring is added when your drawing calls for it.
Can VT machining make custom 4340 Alloy Steel parts to my drawing?
Yes. 4340 Alloy Steel 4340 Alloy Steel gear cutting 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.
Why is 4340 Alloy Steel a good choice for CNC Gear Hobbing?
4340 Alloy Steel is high-strength and hardenable, which makes it well suited to CNC Gear Hobbing. We tune the process to the alloy so the finished 4340 Alloy Steel gear cutting part meets your dimensional and functional requirements.
What is CNC Gear Hobbing 4340 Alloy Steel and how is it done?
CNC Gear Hobbing 4340 Alloy Steel refers to gear hobbing generates gear teeth with a rotating hob synchronized to the workpiece. Applied to 4340 Alloy Steel — high-strength and hardenable — VT machining produces each part to your CAD drawing, selecting parameters from your tolerance, finish and quantity requirements.
What surface finish is achievable on 4340 Alloy Steel with CNC Gear Hobbing?
Surface finish on 4340 Alloy Steel is controlled to your specification; we confirm the achievable Ra against your callout.