Stainless Steel CNC Turning
Grades 303 · 304L · 316L · 17-4PH · Duplex 2205
Precision stainless steel CNC turning and Swiss-type bar turning specialist for connectors, hydraulics, medical and automotive industries. From grade 303 for maximum throughput to 316L precision turning for marine and medical applications. Guaranteed tolerances of ±0.005 mm (5 µm). Competitive pricing from 500 parts.
Guaranteed tolerance
±0.005 mm
Max. bar diameter
Ø 1–65 mm
Certifications
ISO 9001 · IATF
Series handled
500 → 10 M
Machining Stainless Steel: Key Technical Considerations
Stainless steel CNC turning accounts for over 60% of our production volume. Its corrosion resistance, mechanical performance and availability make it the dominant material for industrial connectors, high-pressure hydraulics and medical applications. From small stainless turned parts from Ø 1 mm to components up to Ø 65 mm, our machine park covers the full dimensional range.
Austenitic grades exhibit a tendency to work hardening — the material hardens locally at each tool pass. This characteristic demands precise cutting parameters: a minimum depth of cut to stay below the hardened layer, sustained feeds, and high-pressure coolant (up to 80 bar on our stainless CNC centres) to evacuate heat concentrated in the cutting zone.
Stainless turning on our sliding-head Swiss-type lathes guarantees concentricity of 0.003 mm TIR on slender parts (L/D up to 100:1) — shafts, spindles and threaded rods — impossible to achieve on fixed-headstock machines. Our competitive edge in high-volume stainless bar turning rests on mastery of cycle times, scrap minimisation and raw material cost management (bulk purchasing, rolling stock of 303/304L/316L/17-4PH).
We also produce hexagonal stainless turned parts (SW 4–36 mm) and square section stainless parts (4–25 mm) from profiled bar stock, as well as complex stainless geometries with radial milling, drilling and threading operations integrated in a single Swiss-type cycle or on 5-axis centres.
Competitive advantages
Competitive unit pricing for series stainless turning
Multi-spindle cam lathes: cycle time 8–45 sec. Tooling amortised from 500 parts. Unit cost up to 3× lower than single-spindle CNC for series production.
Consistent quality — precision stainless turning
In-process SPC statistical control. First-article inspection + periodic CMM checks. Scrap rate < 0.5%. Tolerances maintained to ±5 µm across the full production run.
Supplier responsiveness — custom stainless turning
Quote within 24h. Permanent stock of 303/304L/316L/17-4PH bar. Production launch possible within 10 working days. EN 10204 3.1 certificates provided systematically.
Stainless Grade Comparison — 303, 304L, 316L, 17-4PH, Duplex 2205
From standard 303 bar turning to medical-grade 316L and precipitation-hardened 17-4PH, our technical team assists you in selecting the most appropriate grade for your application and cost constraints.
Grade 303
Free-machining austenitic grade with sulphur additions (0.15–0.35%). MnS inclusions act as natural chip-breakers, reducing cutting forces by 20–30%. Reference grade for high-volume stainless steel bar turning.
Typical applications
- ›Industrial fasteners & screws
- ›Shafts and spindles
- ›Connector bodies
- ›Structural brackets
Grade 304L
Universal low-carbon austenitic grade — excellent resistance to atmospheric corrosion and mild acids. Essential for food-grade, connectors and freshwater hydraulic components.
Typical applications
- ›Hydraulic fittings
- ›Food-grade components
- ›Medical screws & nuts
- ›Industrial decorative parts
Grade 316L
Medical ref.Absolute reference for medical, marine and chemical applications. Molybdenum (2–3%) provides chloride and halogenic acid resistance absent in 304L. Dominant grade for precision medical stainless turning.
Typical applications
- ›Medical implants & surgery
- ›Offshore marine equipment
- ›High-pressure chemical valves
- ›Surgical instruments
Grade 17-4PH
Precipitation-hardened martensitic stainless (Cu–Nb phase). High mechanical strength (Rm up to 1,310 MPa after H900 treatment) combined with good corrosion resistance. Machined in annealed condition, heat treated post-machining.
Typical applications
- ›High-strength gears & shafts
- ›Aerospace structural parts
- ›Hydraulic cylinders
- ›Automotive transmission shafts
Duplex 2205
Austenitic-ferritic structure — yield strength twice that of 316L (Re ≥ 450 MPa). Stress corrosion cracking (SCC) resistance in severe chloride environments.
Typical applications
- ›Offshore pumps and valves
- ›Desalination & water treatment
- ›High-pressure chemical equipment
Hexagonal & Square Stainless Bar Turning
Beyond round bar stock, our Swiss-type lathes and multi-spindle cam machines accept hexagonal stainless profiles (SW 4 to 36 mm) and square section stainless bar (4 to 25 mm). This capability eliminates secondary milling operations for nuts, hex standoffs, custom fasteners and valve bodies — reducing cycle time and cost significantly.
Hexagonal bar feeding on a Swiss-type lathe ensures perfect flat-to-flat parallelism and angular indexing within 0.02°, critical for connector bodies, precision fasteners and instrumentation parts that require wrench engagement surfaces. All profiles are supplied with EN 10204 3.1 material certificates traceable to the original melt.
Hex profiles
SW 4–36 mm
ISO 4032 compatible
Square section
4–25 mm
No secondary milling
Max. bar length
3,000 mm
Full bar utilisation
Flatness TIR
≤ 0.02°
Angular indexing
Surface Finishing — Passivation, Electropolishing & Brushed Grain
Complete finishing capability through our qualified subcontractor network — every treatment delivered with a conformity certificate.
Electrochemical Passivation
ASTM A967 / EN 2516
Restores the passive chromium-oxide layer disrupted by machining. Mandatory for medical and food-grade stainless parts. Certificate included.
Electropolishing
Ra < 0.1 µm achievable
Electrolytic micro-levelling — removes surface peaks, improves fatigue resistance. Reference finishing for implantable medical stainless parts and clean-room components.
Brushed / Satin Finish
Grain 180 / 240 / 320
Linear directional brushing for aesthetic and industrial stainless parts. Grain 180 for industrial use, 240/320 for cosmetic and instrumentation applications.
Stress-Relief Shot Peening
SAE J2277
Compressive residual stress introduction to improve fatigue life of loaded stainless turned parts — shafts, springs, gears.
H900 Heat Treatment
AMS 2759/3
Post-machining age hardening for 17-4PH (H900: 1 h at 480°C) achieving Rm up to 1,310 MPa. Performed on machined parts to avoid dimensional distortion.
Electrochemical Etching
Custom mark / logo
Part marking and traceability without mechanical stress. Lot number, batch code or customer logo applied to stainless surfaces without dimensional impact.
Stainless Steel Turning — Frequently Asked Questions
Stainless Steel Turned Parts — Quote within 24h
Our technical team analyses your drawings and provides a detailed proposal within one business day. Permanent stock of 303, 304L, 316L, 17-4PH and Duplex 2205 bar.