Brass & Copper Parts is an experienced manufacturer of stainless steel screw machine parts, offering precision SS turned components to OEMs, distributors, and MRO suppliers across the USA. We combine advanced multi-spindle and CNC Swiss-type screw machining technology with deep metallurgical knowledge of stainless steel alloys to produce high-quality, corrosion-resistant parts that perform reliably in demanding environments.
What Are Stainless Steel Screw Machine Parts?
Stainless steel screw machine parts are precision-turned components manufactured from stainless steel bar stock using automatic or CNC screw machines. Stainless steel is more challenging to machine than brass or aluminum — it work-hardens rapidly, generates high cutting forces, and requires careful management of heat and cutting parameters. However, the resulting parts offer exceptional corrosion resistance, strength, and longevity that make them indispensable in food processing, medical, chemical, marine, and aerospace applications.
Proper grade selection and machining strategy are critical. Free-machining grades like 303 and 416 stainless significantly improve productivity, while grades like 304, 316, and 17-4 PH are selected for their superior corrosion resistance or strength properties.
Our Range of Stainless Steel Screw Machine Parts
We manufacture a wide variety of precision stainless steel screw machined components for critical applications:
Stainless Steel Turned Parts & Precision Shafts
CNC-turned stainless steel parts including stepped shafts, dowel pins, precision shafts, and complex turned profiles. Available in 303, 304, 316, 416, and 17-4 PH stainless for applications demanding tight tolerances and corrosion resistance.
Stainless Steel Fasteners & Threaded Components
Custom stainless steel screws, studs, bolts, and special fasteners machined to ASME B18.6.3, ASTM A193, A194, and F593 standards. Available in 18-8 (303/304), 316, and 410 stainless for general, marine, and high-temperature applications.
Stainless Steel Fittings & Connectors
Precision stainless steel hydraulic fittings, compression fittings, tube stubs, and adapters for ultra-high purity (UHP), pharmaceutical, chemical processing, and food-grade fluid systems. Machined to ASTM A312, A269, and ASME BPE standards.
Stainless Steel Bushings & Spacers
Close-tolerance stainless steel bushings, spacers, and liners for medical devices, pumps, valves, and instrumentation. Produced in 304, 316L, and 17-4 PH for sanitary and corrosive environments.
Stainless Steel Surgical & Medical Components
Ultra-precision 316L and 17-4 PH stainless steel parts for surgical instruments, implantable device components, catheter hubs, and medical equipment. Manufactured to ISO 13485 quality standards with full material traceability and passivation per ASTM A967.
Stainless Steel Standoffs & Threaded Inserts
Corrosion-resistant stainless steel standoffs, female-female and male-female spacers, and panel fasteners for electronics, enclosures, and outdoor equipment exposed to harsh environments.
Stainless Steel Valve Components
Precision-machined stainless steel valve bodies, stems, seats, balls, and plugs for ball valves, needle valves, check valves, and sanitary valves used in chemical, pharmaceutical, and food processing industries.
Stainless Steel Nozzles & Orifice Components
High-precision stainless steel nozzles, orifice inserts, and jet components for fluid control, spray systems, and fuel injection applications requiring corrosion resistance and precise bore diameters.
Stainless Steel Grades for Screw Machine Parts — International Equivalents
We machine all standard austenitic, ferritic, martensitic, and precipitation-hardening stainless steel grades. The table below shows the most common grades and their international equivalents:
| Grade | UNS (USA) | AISI/SAE | BS (UK) | DIN / EN (Europe) | JIS (Japan) | Key Property |
|---|---|---|---|---|---|---|
| 303 (Free-Machining) | S30300 | 303 | 304S31 | 1.4305 / X8CrNiS18-9 | SUS303 | Best machinability in austenitic SS |
| 304 / 304L | S30400 / S30403 | 304 | 304S15 | 1.4301 / X5CrNi18-10 | SUS304 | General purpose, excellent corrosion resistance |
| 316 / 316L | S31600 / S31603 | 316 | 316S31 | 1.4401 / X5CrNiMo17-12-2 | SUS316 | Superior corrosion; marine, chemical, pharmaceutical |
| 410 (Martensitic) | S41000 | 410 | 410S21 | 1.4006 / X12Cr13 | SUS410 | Hardenable, moderate corrosion resistance |
| 416 (Free-Machining) | S41600 | 416 | 416S21 | 1.4005 / X12CrS13 | SUS416 | Best machinability in martensitic SS |
| 430 (Ferritic) | S43000 | 430 | 430S15 | 1.4016 / X6Cr17 | SUS430 | Non-hardenable, good formability |
| 17-4 PH | S17400 | 630 | — | 1.4542 / X5CrNiCuNb16-4 | SUS630 | Very high strength + corrosion resistance |
| 15-5 PH | S15500 | — | — | 1.4545 | — | Aerospace, high strength, toughness |
Machining Stainless Steel: Our Process Expertise
Stainless steel’s work-hardening behavior demands specialized tooling, cutting parameters, and coolant strategies. At Brass & Copper Parts, we use carbide and cermet tooling with optimized geometries, high-pressure through-tool coolant delivery, and carefully calibrated feeds and speeds to maintain dimensional accuracy, surface finish, and tool life. We apply these capabilities to produce stainless steel screw machine parts that meet the tightest tolerances demanded by aerospace, medical, and chemical processing customers.
Industries We Serve Across the USA
- Medical & Surgical: Implant components, surgical instruments, catheter parts, diagnostic equipment
- Food & Beverage Processing: Sanitary fittings, valve components, conveyor hardware (3-A and FDA compliant)
- Chemical & Pharmaceutical: Corrosion-resistant fittings, reactor components, analytical instrument parts
- Marine & Offshore: Deck hardware, fasteners, pump components, propeller shafting
- Oil & Gas: Downhole tool components, valve stems, fittings, wellhead hardware
- Aerospace & Defense: Structural fasteners, precision shafts, hydraulic fittings (DFARS compliant)
- Automotive: Exhaust system components, sensor housings, fuel system fittings
Why Choose Brass & Copper Parts for Stainless Steel Screw Machine Parts?
- Stainless Steel Machining Specialists: Dedicated tooling, fixtures, and process parameters optimized for free-machining and standard austenitic/martensitic stainless grades.
- Precision & Repeatability: Diameter tolerances to ±0.001″ (±0.025 mm) on turned ODs; bore tolerances to ±0.0015″ with excellent surface finish (Ra 1.6 µm or better).
- Full Secondary Operations: In-house thread rolling, slot milling, cross-drilling, form turning, and passivation — all under one roof for complete ready-to-install stainless parts.
- Medical-Grade Capability: ISO 13485-aligned processes, electropolishing, passivation per ASTM A967, and full material traceability for medical device components.
- DFARS Compliance: Domestic melt stainless steel available for defense and government contract requirements.
- ISO 9001:2015 Quality System: CMM inspection, surface roughness measurement, hardness testing, and full dimensional reporting with each order.
- Competitive USA Delivery: DDP shipping to US ports; no surprise import duties. Typical production lead time 3–6 weeks.
Frequently Asked Questions — Stainless Steel Screw Machine Parts
Q1: Why is stainless steel harder to machine than brass?
A: Stainless steel work-hardens during cutting — meaning the material becomes harder as the tool engages it, increasing cutting forces, heat generation, and tool wear. This requires specialized tooling, lower cutting speeds, higher feed rates, and effective cooling. Free-machining grades like 303 and 416 include sulfur additions that improve chip breakage and reduce tool wear, making them the preferred choices for high-volume screw machine production.
Q2: What is the difference between 303 and 304 stainless steel for machined parts?
A: 303 stainless is a free-machining version of 304 that contains added sulfur (0.15% min) to improve machinability. It machines 40–50% faster than 304 with better chip control and surface finish. However, the sulfur reduces corrosion resistance slightly and makes 303 unsuitable for welding. For demanding corrosion environments requiring welding, 304 or 304L is preferred.
Q3: Can you supply passivated stainless steel parts?
A: Yes. We provide passivation per ASTM A967 (citric acid or nitric acid methods) and AMS 2700 for all stainless steel grades. Electropolishing per ASTM B912 is also available for ultra-clean or medical device applications. Passivation certificates are provided with each lot.
Q4: Do you offer DFARS-compliant stainless steel parts for defense contracts?
A: Yes. We can source DFARS-compliant (melted and manufactured in the USA or qualifying countries per DFARS 252.225-7014) stainless steel bar stock and provide the required compliance certifications for defense and government contracts.
Q5: What tolerances can you hold on stainless steel screw machine parts?
A: Standard production tolerances are ±0.001″ to ±0.002″ on turned diameters and ±0.003″ on lengths. For precision applications (medical, aerospace), we can hold ±0.0005″ on diameters with 100% inspection. Thread tolerances per ASME B1.1 Class 2A/2B or Class 3A/3B as required.
Q6: Can you machine 316L stainless for pharmaceutical and food contact applications?
A: Yes. 316L (UNS S31603) is our standard grade for sanitary, pharmaceutical, and food-contact applications. We produce parts that meet 3-A Sanitary Standards, FDA 21 CFR, and ASME BPE surface finish requirements. Electropolishing to Ra ≤0.5 µm is available for ultra-clean applications.
Q7: What is the typical surface finish achievable on stainless steel turned parts?
A: As-machined surface finish on stainless steel screw machine parts is typically Ra 1.6–3.2 µm (63–125 µin). With additional polishing or electropolishing, Ra values of 0.2–0.8 µm (8–32 µin) are achievable for medical and high-purity applications.
Quality Certifications & Compliance
Brass & Copper Parts operates under ISO 9001:2015 certification. Stainless steel screw machine parts are manufactured in compliance with ASTM A582 (free-machining stainless rod), ASTM A276, ASTM A479, and relevant ASME standards. We support PPAP, FAI, material certification (MTCs), and ongoing process capability documentation for all production parts.
Get a Quote on Stainless Steel Screw Machine Parts
Ready to source precision stainless steel screw machine parts from a trusted manufacturer? Upload your drawings or 3D models to Brass & Copper Parts for a competitive quotation. Our engineering team will review your requirements, suggest optimal grade selection, and provide a detailed proposal within 24–48 hours. Contact us today for expert stainless steel screw machining support.
