Stainless Steel CNC MaCHINING
Resolute Precision Manufacturing machines stainless steel precision components across our full CNC capability — Swiss CNC for small-diameter components, bar-fed turning for production volumes, and vertical and horizontal milling for housings and structural components. We produce stainless components in 303, 304, 316L, 17-4 PH, and 15-5 PH in quantities from single prototypes to high-volume production. ISO 9001 certified. 24-hour quote response. Request a QuoteWhy Stainless Steel Requires Specific Machining Knowledge
Stainless steel is significantly more challenging to machine than carbon steel or aluminum. Austenitic grades such as 303, 304, and 316 can work-harden rapidly during machining. If cutting parameters allow the tool to dwell or rub rather than cut continuously, the surface can harden, causing subsequent passes to encounter a harder, more abrasive workpiece. This work hardening can contribute to poor surface finish and accelerated tool wear.
Successful Stainless Steel CNC Machining requires sharp tooling, continuous cuts without tool dwell, appropriate feed rates that keep the tool engaged, and sufficient cutting fluid to manage heat. Resolute Precision’s machinists apply appropriate process parameters for each stainless steel grade to produce Stainless Steel CNC Machined Parts with the dimensional accuracy and surface finish required for demanding industrial applications.
Stainless Steel Grade Selection Guide
Selecting the right stainless steel grade is an important first step in producing a successful machined component.
303 Stainless Steel — One of the most machinable austenitic stainless grades. Its sulfur addition improves chip breaking and machinability. It is generally selected for machined components where welding is not required.
304 and 304L Stainless Steel — Widely used stainless grades offering good corrosion resistance and weldability. They are commonly used for food processing, chemical processing, and general industrial applications.
316 and 316L Stainless Steel — Molybdenum provides improved resistance to chloride pitting and crevice corrosion compared with 304. These grades are commonly used in marine, medical, chemical processing, and other corrosive environments. 316L is the low-carbon version and is commonly specified for welded assemblies.
17-4 PH Stainless Steel — A precipitation-hardening stainless steel that can be heat treated to achieve high strength. H900 can reach approximately 200–220 ksi tensile strength depending on specification and condition. It provides a strong combination of mechanical strength and corrosion resistance for demanding applications.
15-5 PH Stainless Steel — A precipitation-hardening stainless steel offering high strength and corrosion resistance with good toughness. It is commonly used for aerospace, defense, and structural components.
Specifications
| Grades | 303, 304, 304L, 316, 316L, 17-4 PH, 15-5 PH; standard stocked grades with additional grades available upon request |
| Turning | Swiss CNC (20mm–38mm) for small-diameter parts; bar-fed and chucked turning for larger components |
| Milling | 3, 4, and 5-axis vertical milling; horizontal milling for multi-face parts and castings |
| Tolerances | ±0.001″ standard; ±0.0005″ on precision surfaces with appropriate process controls |
| Surface Finish | Ra 32–63 microinch standard; Ra 16 available with fine finishing; electropolishing coordinated through qualified outside service providers |
| Passivation | Coordinated per ASTM F86 and AMS 2700; standard for medical and food-contact stainless steel components |
| Heat Treat (PH Grades) | 17-4 PH (H900 through H1150) and 15-5 PH heat treatment conditions coordinated through qualified outside heat treatment providers |
| Volume | 1 prototype through high-volume production |
| Certifications | ISO 9001:2015 |
Stainless Steel Applications From RPM
Resolute Precision Manufacturing produces Stainless Steel CNC Machined Parts for applications where corrosion resistance, strength, durability, and dimensional precision are important.
Medical Devices — 316L components and instrument bodies manufactured to applicable material and customer specifications.
Food and Beverage — 304 and 316 components for food processing and production equipment.
Marine — 316 hardware, fittings, and other components for appropriate above-waterline marine applications.
Chemical Processing — 316 and 316L valve components, fittings, and other parts used for corrosive fluid handling.
Aerospace — 17-4 PH and 15-5 PH fittings, fasteners, brackets, and structural components manufactured to applicable customer and industry requirements.
Industrial Equipment — 303, 304, 316, and precipitation-hardening stainless steel components for industrial machinery and equipment.
Industries We Serve
CNC Turning Services
CNC Milling Services
Custom Fasteners
Value-Added Services
Frequently Asked Questions
Q: What is the difference between 304 and 316 stainless?
A: 304 stainless provides good corrosion resistance in most environments. 316 stainless adds 2–3% molybdenum, which provides substantially better resistance to chloride pitting and crevice corrosion — particularly important in marine environments, chemical service, and medical applications. 316L (low carbon) is specified for welded assemblies to prevent carbide precipitation at weld heat-affected zones.
Q: Does RPM passivate stainless parts after machining?
A: Yes. Through our outside coating services, we coordinate passivation per ASTM F86 (medical applications) or AMS 2700 (general aerospace/industrial). Passivation removes free iron from the machined surface that machining tools deposit, restoring the chromium oxide layer that gives stainless its corrosion resistance.
Q: Can RPM machine 17-4 PH stainless before or after heat treatment?
A: Both. We typically machine 17-4 PH in the annealed condition (Condition A), then coordinate heat treatment to the required condition (H900, H1025, etc.) through our outside operations. Where heat treat distortion must be minimized, we machine after heat treatment at the fully hardened condition. We advise on the appropriate sequence during quoting.
Q: What is the hardest stainless grade RPM can machine?
A: We machine 17-4 PH in H900 condition (Rc 40–44) and 440C stainless in the hardened condition (Rc 55–60). Hardened stainless machining requires carbide tooling and specific cutting parameters — contact us for a feasibility assessment on hardened stainless components.