VT machining offers CNC Turning for 420 Stainless Steel (UNS S42000 / 1.4021-1.4034), typically supplied annealed or hardened. Higher carbon than 410 reaches greater hardness; machined annealed then hardened.
CNC Turning Notes for 420 Stainless Steel
On the lathe 420 Stainless Steel needs chip-breaker inserts and constant chip load to avoid long, stringy swarf.
For estimating, a 100 × 100 × 10 mm block of 420 Stainless Steel weighs about 0.77 kg.
Starting Parameters for CNC Turning 420 Stainless Steel
| Cutting speed (carbide) | 120-220 m/min |
|---|---|
| Feed | 0.08-0.25 mm/rev |
| Spindle speed, Ø25 mm bar | 1530-2800 rpm |
| Insert / tool class | ISO M — positive-rake PVD/CVD carbide |
| Coolant | Flood emulsion (8-10%) or high-pressure coolant |
Starting values for 420 Stainless Steel, Annealed or hardened; optimised on the first article.
420 Stainless Steel Data Relevant to CNC Turning
| Equivalent designations | UNS S42000 / 1.4021-1.4034 |
|---|---|
| Key composition | Cr 12-14%, C 0.15-0.4% |
| Typical supply condition | Annealed or hardened |
| Hardness (typical) | Up to ~50 HRC |
| Machinability rating | 45% (AISI B1112 = 100%) |
Typical values; we work to your drawing and mill certificate.
How 420 Stainless Steel Differs
Higher carbon than 410 reaches greater hardness; machined annealed then hardened.
Typical applications: Surgical instruments, molds, knife blades.
420 Stainless Steel vs Similar Grades
| 420 Stainless Steel | 416 Stainless Steel | 430 Stainless Steel | 410 Stainless Steel | |
|---|---|---|---|---|
| Key composition | Cr 12-14%, C 0.15-0.4% | Cr 12-14%, S ≥0.15% | Cr 16-18% | Cr 11.5-13.5% |
| Hardness | Up to ~50 HRC | ~20 HRC annealed; up to ~40 HRC | ≤88 HRB | ~20 HRC annealed; up to ~45 HRC hardened |
| Tensile (MPa) | ≥655 annealed | ≥485 annealed | ≥450 | ≥450 annealed |
| Machinability % | 45 | 85 | 54 | 55 |
| Typical use | Surgical instruments, molds, knife blades | Screw-machine parts, valve stems, gears, motor shafts | Appliance panels, trim, magnetic parts | Valve trim, pump shafts, cutlery, fasteners |
More on CNC Turning Stainless Steel
Finishing options, quality documentation and general cnc turning guidance for all stainless steel grades are on our CNC Turning Stainless Steel page.
No drawing yet? Sketch the part in our free 3D + 2D builder and send it with your RFQ.
Quoting CNC Turning 420 Stainless Steel
Send a STEP/IGES model or PDF drawing, confirm 420 Stainless Steel and its condition (we usually see it supplied annealed or hardened), the quantity, critical tolerances and any finish or certificate requirements.
420 Stainless Steel in Other Processes
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Send the drawing, the 420 Stainless Steel condition and the quantity — pricing and lead time come back the same or next business day.
Request a QuoteFrequently Asked Questions
What surface finish is achievable on 420 Stainless Steel with CNC Turning?
Surface finish on 420 Stainless Steel is controlled to your specification; we confirm the achievable Ra against your callout.
What material thickness or size range suits CNC Turning 420 Stainless Steel?
Turned 420 Stainless Steel parts are produced from bar or chuck stock across a wide diameter range.
Does CNC Turning 420 Stainless Steel require dedicated tooling?
Most 420 Stainless Steel turning work uses standard cutting tools and CNC programs; dedicated fixtures are made only when geometry or volume requires them.
What tolerances can you hold for CNC Turning 420 Stainless Steel?
Achievable tolerances for 420 Stainless Steel turning depend on the alloy, geometry and feature size. Turning holds diameter tolerances to around ±0.005 mm with concentricity within 0.01 mm. Exact figures are confirmed against your drawing callouts.
Which industries use CNC Turning 420 Stainless Steel parts?
CNC Turning 420 Stainless Steel parts are used across aerospace, medical, automotive, electronics, semiconductor and general industrial sectors — anywhere precise 420 Stainless Steel components are required.
Can VT machining make custom 420 Stainless Steel parts to my drawing?
Yes. 420 Stainless Steel turning 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.