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Should I use brass or stainless steel for turned parts?
Use C360 brass for turned fittings, connectors and inserts where cycle time and conductivity matter: it machines about four times faster than 303 stainless, and its chips carry high scrap value. Use 303 when parts must be stainless or lead-free, need higher tensile strength, or face ammonia or water that dezincifies brass. C360's 2.5–3.0% lead rules it out for drinking-water parts.
Brass C360 (free-cutting)
Stainless steel 303
By the numbers
Priced on the same representative part: turned shaft, screw machining, 10,000 pcs.
Tensile strengthMPa
C360 brass
400
303 SS
620
Yield strengthMPa
C360 brass
310
303 SS
240
Densityg/cm³
C360 brass
8.49
303 SS
8
Elongation%
C360 brass
25
303 SS
50
Raw material cost$/kg
C360 brass
10
303 SS
6.5
Which should you pick?
Pick C360 brass when
- Screw machine volume where cycle time sets price
- Electrical connectors, terminals and contacts
- Threaded inserts for molded plastics
- Parts will be nickel or chrome plated
Pick 303 SS when
- The part must be stainless: food equipment, lab or medical hardware (non-implant)
- Lead is not allowed
- Ammonia or dezincifying water is present
- Tensile strength must exceed about 58 ksi (400 MPa); annealed 303 runs about 90 ksi (620 MPa)
Key differences
| C360 brass | 303 SS | |
|---|---|---|
| Lead | 2.5–3.0%; not for potable water under NSF/ANSI 372 | Lead-free |
| Cutting speed | Highest practical speeds; small broken chips | About a quarter of brass; still the fastest 300-series stainless |
| Corrosion weak spots | Dezincification in aggressive water; ammonia stress cracking | Sulfide inclusions weaken it in chlorides and acids |
| Electrical conductivity | About 26% IACS | Low; not used as a conductor |
| Plating | Plates easily with nickel, chrome and tin | Usually left bare and passivated |
| Scrap value | High; offsets metal cost | Lower per pound |
Questions
Is brass or stainless cheaper to machine?
Brass, per part, in most turned work. C360 costs more per kilogram than 303, but it cuts about four times faster, wears tools less, and its chips return high scrap value, which usually outweighs the metal price.
Can C360 brass be used for drinking water fittings?
No. Its 2.5–3.0% lead exceeds the 0.25% weighted-average limit of NSF/ANSI 372. Use a low-lead brass such as C69300 or C27450, or stainless steel.
Which resists corrosion better, brass or 303 stainless?
303 in most atmospheres and chemicals. C360 does well in fresh water and air but can dezincify in high-chloride or low-pH water and stress-crack in ammonia. 303 is weaker in chlorides than 304, so use 316 for salt exposure.
Try both on your part.
The builder prices the same geometry in every suitable process and material, with DFM for each.