Metal · Material guide
Custom stainless steel parts from independent machine shops
Stainless steel is the default when a part has to resist corrosion, take heat, or stay clean. Upload a drawing and hear back from shops that machine and fabricate 303, 304, 316, and 17-4 every day.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential
Stainless steel shops on OpenSpindle
Real shops that machine and fabricate stainless steel. See their equipment and talk to the person making your part.
★ Top rated
"Precision Waterjet & CNC Plasma Cutting for Any Material, Any Design."
★ Top rated
"Precision CNC Machining & Fabrication Near Austin - 40+ Years"
"Rapid Prototyping, Digital Manufacturing & CNC Machining Since 1994"
"Multi material experiential and retail fabrication in Brooklyn"
"Custom metal fabrication and precision machining in Baton Rouge"
"Precision Waterjet & CNC Cutting in Central Texas"
Grades
Stainless steel grades shops run most
The grade sets corrosion resistance, strength, and how easily it machines. These are the ones you will see quoted; if yours is not here, ask when you request a quote.
303
The free-machining austenitic grade. Sulfur added to 304 chemistry lets it cut fast and clean, at the cost of some corrosion resistance and weldability. The default when you need many turned stainless parts.
Best for Turned fittings, shafts, fasteners, and high-volume machined parts
304 / 304L
The general-purpose stainless. Excellent corrosion resistance, non-magnetic, and food-safe, though it work-hardens and machines slower than 303. 304L has lower carbon for better weldability.
Best for Enclosures, brackets, food and dairy, general fabrication
316 / 316L
Adds molybdenum for far better resistance to chlorides, salt water, and harsh chemicals. The marine and medical grade. More expensive and gummier to machine than 304.
Best for Marine, chemical process, medical, and outdoor coastal parts
17-4 PH
A precipitation-hardening stainless with strength approaching alloy steel plus good corrosion resistance. Machined in the annealed condition then heat treated (H900, H1075) to spec. Magnetic.
Best for High-strength shafts, valve and pump parts, aerospace hardware
15-5 PH
Similar to 17-4 but with better toughness and transverse properties from a more refined microstructure. Also precipitation-hardened to a range of tempers. Common in aerospace structure.
Best for Aerospace structural parts, high-strength corrosion-resistant hardware
440C / 416
Hardenable martensitic grades. 440C reaches high hardness (~58 HRC) for wear and edge retention; 416 is the free-machining martensitic grade that heat treats and takes magnetism.
Best for Knife blades, bearings, valve seats, wear parts, magnetic components
Specs
Material properties
Representative values for 304 in the annealed condition, the most common machining grade. Exact numbers vary by grade and temper.
| Property | Typical value |
|---|---|
| Density | 8.0 g/cm³ (0.29 lb/in³) |
| Tensile strength (304) | ~73-90 ksi (515-620 MPa) |
| Yield strength (304) | ~30 ksi (205 MPa) |
| Tensile strength (17-4 H900) | ~190 ksi (1310 MPa) |
| Hardness (304 annealed) | ~70-85 HRB |
| Max service temp | ~870 °C (1600 °F) intermittent for 304 |
| Machinability | Moderate; 303 best, 304/316 work-harden and run gummy |
| Corrosion resistance | Excellent; 316 outperforms 304 in chlorides |
| Weldability | 304L/316L good; avoid welding 303 |
Stainless work-hardens, so it wants sharp tools, rigid setups, and steady feeds. That is why a stainless part costs more to machine than the same part in aluminum or mild steel.
Stock
Forms we machine it from
Plate & block
Milled and 5-axis parts machined from solid.
Round bar
Turned shafts, fittings, and cylindrical parts.
Sheet
Laser, waterjet, and press-brake sheet metal.
Processes
Manufacturing methods for stainless steel
The right process depends on part geometry, tolerances, and production volume.
Finishing
Finishes for stainless steel
Stainless is usually left bare because the metal itself resists corrosion. Finishing focuses on restoring that resistance and setting surface texture, not adding a coating.
Passivation
A nitric or citric acid bath that dissolves free iron from the surface and lets the natural chromium oxide layer reform. Standard on medical and food parts (ASTM A967). Does not change dimensions.
Electropolish
An electrochemical process that removes a thin surface layer for a bright, smooth, ultra-clean finish. Improves corrosion resistance and cleanability, common in medical and semiconductor parts.
Bead blast
A uniform matte texture that hides machining marks. Often specified as a cosmetic finish before passivation.
Tumbling / deburr
Mass finishing that breaks edges and evens the surface on small turned or stamped parts. Good for high-volume runs.
As-machined
No finish beyond deburring. Fine for internal or non-cosmetic parts, though passivation is still recommended for corrosion service.
Stainless does not anodize like aluminum. If a part needs color or a hard coating, call it out and the shop confirms what is possible for the grade.
Applications
Where stainless steel parts are used
Stainless shows up wherever corrosion, hygiene, heat, or strength rule out aluminum and plain steel.
Compare
Stainless Steel vs other materials
How stainless steel stacks up against the other metals shops quote most.
Stainless Steel vs Aluminum
Aluminum →- Stainless is far stronger and harder, and resists corrosion without any coating
- Aluminum is about one-third the weight and machines several times faster
- Stainless holds up better at high temperature and in food, marine, and chemical service
Choose stainless for strength, hygiene, and corrosion in tough environments. Choose aluminum for light weight, speed, and cost.
Stainless Steel vs Carbon steel
Carbon steel →- Stainless resists corrosion on its own; carbon steel rusts and needs a coating or oil
- Carbon steel is cheaper per pound, machines more easily, and can reach very high hardness
- Stainless keeps its properties in wet, salty, or sanitary environments where carbon steel fails
Choose stainless when corrosion or cleanliness matters. Choose carbon steel for lower cost and easier machining where a finish handles rust.
Stainless Steel vs Titanium
Titanium →- Titanium has a much higher strength-to-weight ratio and is roughly half the weight of stainless
- Stainless is several times cheaper and easier to source and machine
- Both resist corrosion well and are biocompatible, but titanium leads in seawater and implant use
Choose stainless for cost and general corrosion service. Choose titanium when weight, seawater, or biocompatibility justify the premium.
Questions
Frequently asked questions
Both are austenitic, non-magnetic, and corrosion resistant, but 316 adds molybdenum that greatly improves resistance to chlorides, salt water, and harsh chemicals. 304 is the general-purpose default and costs less; 316 is the marine, medical, and chemical grade. Use 304 for most parts and 316 when the part sees salt, acids, or coastal exposure.
Get stainless steel part quotes
Upload a drawing once and compare quotes from independent shops that machine, cut, and finish stainless steel.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential