Stainless steel parts we machine cover food-contact fittings, marine hardware, medical-style components and industrial equipment: 303 for free-machining fittings, 304 for general corrosion resistance, 316L for chloride and marine environments, 17-4PH where strength matters.
Correct grade selection, tool paths and passivation are what make stainless parts perform in the field — we flag corrosion-relevant callouts during DFM review.
Key Specifications
| Specification | Value |
|---|---|
| lead time | 7 days |
| tolerance | ±0.002 in |
| lead time | 80 days |
| lead time | 120 days |
| surface finish | Ra0.6 |
Material Grades & Properties
Stainless Steel Grades We Machine
| Grade | Standard | Characteristics |
|---|---|---|
| 304 | ASTM A240 | General purpose austenitic; excellent corrosion resistance; work-hardens. |
| 316/316L | ASTM A240 | Added molybdenum for chloride resistance; marine and medical use. |
| 17-4 PH | ASTM A564 | Precipitation hardening; high strength after heat treatment; aerospace/medical. |
| 303 | ASTM A582 | Sulfur-added free-machining grade; best machinability of austenitic; lower corrosion resistance. |
Key Properties of Machined Stainless Steel
- ✓Corrosion resistance
- ✓High strength
- ✓Heat resistance
- ✓Hygienic (food/medical compatible grades)
Typical tolerances:±0.05 mm standard; ±0.01 mm achievable with finishing
Applications for Stainless Steel Parts
- Medical instruments and implants
- Food processing equipment
- Marine hardware
- Valves and fittings
- Aerospace components
Machining Notes for Stainless Steel
Work-hardens quickly: maintain consistent feed, sharp tooling, adequate coolant. 303 machines easiest; 316 slowest of the common grades.
Finishes for Stainless Steel Parts
- Passivation
- Electropolishing
- Bead blasting
- Vibratory finishing
Capabilities
- 303/304/316L/17-4PH machining to drawing
- Passivation per customer spec
- Electropolishing on request
- Thread and fitting geometry in one setup
Typical materials
Stainless 303, 304, 316/316L, 17-4PH, 410, 416, duplex on request.
| Material / grade | Typical condition | Machinability | Where it fits |
|---|---|---|---|
| Aluminium 6061 | T6 (solution treated and aged) | Easy: free-cutting, good chip control | Brackets, housings, fixtures, prototypes into production |
| Aluminium 7075 | T6 / T651 | Harder: more tool wear, needs rigid setups | High-strength, weight-critical parts; not for welding |
| Stainless 304 / 304L | Annealed | Work-hardens: slower speeds, positive feed | General corrosion resistance, food and process equipment |
| Stainless 316 / 316L | Annealed | Tougher than 304: more tool wear | Chloride, marine, medical and pharmaceutical exposure |
| Carbon steel 1018 / 1045 | As-rolled / normalised | Easy to moderate; needs protection against rust | Shafts, plates, weldments, tooling bodies |
| Brass C360 | H02 half hard | Excellent: high speeds, clean finish | Fittings, bushings, connectors, decorative parts |
| Copper C110 | Annealed / H02 | Gummy: sharp tools and high rake angles | Conductivity, busbars, thermal management |
| Titanium Grade 5 (Ti-6Al-4V) | Mill annealed | Difficult: low speeds, heat control, tool wear | Aerospace, medical and lightweight high-strength parts |
| Engineering plastics (POM, PEEK, PA) | Extruded / annealed | Easy to gummy: soft jaws, sharp tooling | Insulation, low friction, chemical and wear parts |
Finishes
Passivation, electropolishing, bead blasting, polishing, black oxide.
| Finish | What it does | Specify it when |
|---|---|---|
| As machined | Tool marks left visible; Ra typically 1.6-3.2 µm | The part only has to function |
| Bead blast | Uniform matte surface, hides tool marks | Cosmetic parts before anodising |
| Anodising Type II | Builds an oxide layer; colour options | Aluminium appearance plus mild corrosion and wear resistance |
| Hard anodising Type III | Thicker, harder oxide layer | Sliding or wearing aluminium surfaces |
| Chromate conversion | Thin protective film that stays conductive | Electrical bonding or grounding on aluminium |
| Electroless nickel | Uniform, hard, corrosion-resistant layer | Wear plus corrosion, including inside bores |
| Zinc plating | Economical sacrificial corrosion protection | Steel parts in indoor or sheltered service |
| Powder coat | Thick, durable, decorative layer | Appearance is the requirement |
| Passivation | Removes free iron and restores the oxide film | Stainless parts after machining |
| Stress relief / heat treatment | Relieves residual stress before or after cutting | Thin walls and tight tolerances that must survive machining |
Tolerances
ISO 2768-m standard; ±0.01 mm on critical features.
| Callout | What it needs | Effect on cost and lead time |
|---|---|---|
| General: ±0.25 mm / ±0.010 in | Standard tooling, dimensional check | Baseline: no adder |
| Standard: ±0.13 mm / ±0.005 in | Machine in good condition, first-article check | Small adder; the usual quoting default |
| Tight: ±0.025 mm / ±0.001 in | Ground or diamond tooling, temperature control, CMM | Step change: slower cuts plus full inspection |
| Precision: ±0.013 mm / ±0.0005 in | Finish passes, gauging, controlled environment | Machining dominates the price; often a separate operation |
| Position / angularity (GD&T) | Datum control, one setup where features are related | Depends on how many setups the datum spans |
| Surface finish Ra 0.8 µm or finer | Finer stepovers, polishing or a finishing pass | Adds a process step, not just machining time |
Materials We Machine
- Brass
- Copper
- Stainless Steel 201
- Titanium
- iron
- molybdenum
- nickel-pig-iron
- raw materials
- steel
Common Applications
- Airplane Parts
- Chemical Housings
- Cover
- Decorative/Architectural
- Equipment Panels
- Food parts
- Food-Contact
- Freshwater Environment
- Marine Parts
- Marine hardware
- Medical Machines
- Micro Mechanical Parts
- Oxidizing Environment
- Stainless Steel CNC Machining
- Water Pipes
- Weak Acids
- architectural design
- chloride-rich environments
- city buildings
- corrosive process environments
- critical fasteners
- dive watch
- folding hinges
- food machines
Process Options
- CNC machining is a subtractive manufacturing process.
- Finishing Options: Black Oxide, Electropolishing, ENP, Media Blasting, Nickel Plating, Passivation, Powder Coating, Tumble Polishing, Zinc Plating, Vibratory Tumbling
- EPX 82 is processed using Carbon DLS
- MUD is a type of mold that uses a standard injection molding frame.
- Different taper turning methods suit different jobs. Compound slides often handle short tapers, while CNC interpolation and taper attachments improve repeatability on longer parts
- G92 is used by programming one or more G92's right after the G76 threading cycle
- Estimates are provided through an auto-quoted method.
- EDM relies on a voltage and a thin wire
- Advanced machining processes like micro-machining and EDM are used to create small, precise mold cavities and cores
Surface Finish Reference
- The finish of MoldTech MT11010 is a fine matte texture.
- The finish of MoldTech MT11020 is a medium matte texture.
- The finish of MoldTech MT11030 is a coarse matte texture.
- SPI A-1 has a surface roughness of 0.012–0.025 µm.
- SPI B-2 has a finish of Medium semi-gloss.
- SPI B-2 has a surface roughness of 0.10–0.15 µm.
- SPI C-3 has a surface roughness of 0.63–0.70 µm.
- Super high gloss, polished with a Grade #3 (6000-grit) diamond buff to Ra 0.012–0.025 µm.
- Medium semi-gloss, finished with 400-grit paper to Ra 0.10–0.15 µm.
- Normal matte, polished with 320-grit stone to Ra 0.63–0.70 µm.
Tolerance Reference
- The tolerance with drawing for CNC Milling is as low as +/- 0.005 mm.
- FDM 3D printing offers a low-cost component with average accuracy and uses thermoplastics for 3D printing.
- Wire Cut EDM is highly accurate.
- The U6 H.E.A.T machine achieves tight tolerances.
- Die sinker EDM is capable of maintaining tight tolerances
- The shop needs to have CNC machines that can achieve a specific tolerance.
Industries We Serve
- antennas
- automotive
- CNC machined parts
- custom parts
- electronics
- medical diagnostic
- optical displays
- optical_systems
Material Reference
- ABS
- Austenitic Stainless Steel
- Carbon steel
- ceramic
- composites
- Copper - T2
- copper or graphite
- Hardened Materials
- High Impact Polystyrene
- Low-density polyethylene
- MDF
- metal
- Polybutylene Terephthalate
- SUS304
- thermoplastics
- thick metal sheets
- tungsten carbide
Frequently asked questions
Which stainless grade for a marine environment?
316L is the default for chloride exposure. For high-strength marine hardware, 17-4PH in condition H900 is common; confirm with your environment data.
Do you provide material certificates?
Yes, mill test certificates (EN 10204 3.1 where required) are available with the shipment on request.
Can you machine food-contact fittings?
Yes. Specify sanitary requirements on the drawing — we machine smooth internal radii and surface finishes typical for sanitary fittings.
What is the minimum order quantity (MOQ)?
Prototypes from 1 pc. Low-volume production typical 50-500 pcs. No forced MOQ on custom parts; unit price drops with volume.
What is the typical lead time?
Industry benchmark: instant-quote platforms deliver prototypes in 1-3 business days. Our own production: prototypes 5-10 working days, including in-house QC and shipping. Production: 2-4 weeks depending on quantity/finishing. Express options exist; finishing adds days.
How do I get a quote and what information do you need?
3D files (STEP/IGS) + 2D drawing with tolerances. Material, quantity, finish, destination country. Quote turnaround: 24-48h typical.
What tolerance should I specify?
Specify tight tolerances only on critical features. Standard ±0.1 mm covers most features. Tighter tolerance = cost multiplier; apply selectively via drawing GD&T.
How is quality controlled?
First-article inspection in our own shop before the first production order. In-process checks. Final inspection report (dimensions) with shipment. Material certs (mill test reports) on request.
Is my design protected?
NDA before file exchange. Files used only for your production. No resale of custom designs.
Which surface finish do I need?
Anodizing for aluminum corrosion/wear/color. Passivation for stainless. Plating for conductivity/steel protection. Cosmetic vs functional distinction.
How do you ship and what terms?
DHL/FedEx/UPS express for samples and small batches. Air/sea freight for production volumes. Incoterms: EXW/FOB/DAP/DDP options.
Sources · 4
- seathertechnology.comUnclassified source
- fictiv.comIndustry peer technical page
- actionstainless.comUnclassified source
- yshsteel.comUnclassified source
Technical references cited for verifiability — not supplier recommendations. Browse the research library.