For a part that is machined in volume, free-cutting brass (C36000 / CW614N) is far cheaper and faster to cut — it sits at 100 on the copper-alloy machinability scale, while free-machining 303 stainless is around 78 and 304/316 are far lower (~45 and ~36 on the steel scale). Stainless earns its place when you need higher strength and stiffness (roughly double the elastic modulus), aggressive or chloride corrosion resistance (316 with molybdenum), or food-contact, medical and high-temperature service. Brass and stainless are close in density (both about 8 g/cm³), so brass carries no real weight penalty here — the real gulfs are machinability and conductivity.
Brass and stainless steel are the two metals most often weighed against each other for small machined components — fittings, connectors, manifolds, spindles, terminals. They are close in one surprising respect (density) and worlds apart in others (how freely they cut, and how well they conduct). This guide lays out the engineering facts side by side, then gives an honest account of where each material genuinely wins.
Brassland machines precision components in brass, copper and aluminium — we do not machine stainless — so treat this as a neutral engineering comparison rather than a pitch. If your part belongs in stainless, we will tell you.
Read machinability numbers with care
Two different reference scales are in play. Free-cutting brass is rated on the copper-alloy machinability scale, where C36000 / CW614N = 100. Steel and stainless are rated on the steel free-machining scale, where AISI B1112 = 100. Both scales happen to use 100 as their datum, so the figures compare in spirit — "how freely does it cut" — but they are not two points on one physical ruler. Treat any cross-family machinability figure as indicative, never as an exact ratio.
Brass vs stainless: the numbers side by side
The table compares free-cutting brass with the three stainless grades most commonly specified for machined parts: 303 (free-machining), 304 (general purpose) and 316 (marine / chemical). Where sources disagree, the figure is flagged.
| Property | Free-cutting brass (C36000 / CW614N) | SS 303 | SS 304 | SS 316 |
|---|---|---|---|---|
| Machinability (free-machining index, higher = easier) | 100 (copper-alloy datum) | ~78 | ~45 | ~36 |
| Density (g/cm³) | ~8.4–8.5 | ~7.9–8.0 | ~7.9–8.0 | ~8.0 |
| Elastic modulus (GPa) | ~100 | ~193–200 | ~193–200 | ~193–200 |
| Ultimate tensile strength (MPa) | ~330–530 | ~500–620 | ~580–1180 (cold-worked range) | ~480–620 |
| Thermal conductivity (W/m·K) | ~120 | ~16 | ~16 | ~16 |
| Electrical conductivity (% IACS) | ~26–29 | ~2.4 | ~2.4 | ~2.4 |
| Corrosion strategy | Naturally resistant; DZR grades (e.g. CW602N) resist dezincification; not first choice in strong chloride/acid | Passive Cr-oxide film; poorer chloride pitting resistance than 316 | Passive film; good general corrosion resistance | Best here — Mo addition gives superior chloride/pitting resistance |
| Relative raw cost per kg | Higher than commodity stainless at scrap level, but volatile (tracks copper + zinc) | — | Lower per kg than brass at commodity level | Highest of the three stainless grades (Mo/Ni loaded) |
| Cost to machine | Lowest — high surface speed, long tool life, clean chips | Moderate | High (work-hardens, slower feeds) | Highest (Mo, gummy, tool wear) |
A note on the density line: some datasheets list C36000 at about 8.2 g/cm³ and 304 at about 7.8 g/cm³. Brassland's canon fixes brass at 8.4–8.5 g/cm³, which is what we use here. Either way the practical conclusion is the same — brass and stainless are close in density, so brass does not carry the weight penalty against stainless that it does against aluminium. The real differences are elsewhere: brass conducts roughly 7–8× the heat and about 10× the electricity, and it machines in a different league.
Where the two materials really differ
Machinability and cost to machine
This is the headline story. Free-cutting brass is the benchmark the whole copper-alloy scale is built on — 100. Even the free-machining stainless, 303, is around 78 on the steel scale, and 304 and 316 fall to roughly 45 and 36. In the shop that translates to higher cutting speeds, longer tool life, cleaner chip breaking and lower cost per part on brass. On a turned part made in volume, brass's lower cost-to-machine frequently beats its higher price per kilogram on the finished-part total.
Strength and stiffness
Stainless wins decisively here. Austenitic stainless has roughly double the elastic modulus of free-cutting brass (about 193–200 GPa versus ~100 GPa) and higher ultimate tensile strength — 304 can reach 580–1180 MPa in cold-worked conditions against brass's ~330–530 MPa. For a structural or load-bearing part, stainless has the edge; for a fitting, connector or conductive component, brass's strength is usually ample.
Corrosion
Standard brass is naturally corrosion-resistant but can suffer dezincification in aggressive water. Dezincification-resistant (DZR) grades such as CW602N were developed specifically for demanding water and seawater fittings and pass ISO 6509 testing. Stainless relies on a passive chromium-oxide film; 316, with added molybdenum, is the benchmark for chloride and pitting resistance. For continuous strong-chloride structural exposure, 316 is safer; for potable and seawater plumbing fittings, DZR brass is common and proven.
Conductivity
Brass is far ahead — about 10× the electrical conductivity (~26 vs ~2.4 % IACS) and roughly 7–8× the thermal conductivity (~120 vs ~16 W/m·K). For terminals, contacts and heat paths, brass is the clear pick. Stainless's low conductivity is sometimes even desirable, for example where you want to minimise heat loss.
When each wins (honest)
Brass wins when…
The part is machined in volume (screw-machine or CNC-turned fittings, connectors, manifolds); you need electrical or thermal conductivity (terminals, heat paths); you want low tool cost and fast cycle times; and for general plumbing or gas duty where DZR grades handle the corrosion. On a turned part, brass's lower cost-to-machine often beats its higher price per kilogram.
Stainless genuinely wins when…
You need high strength or stiffness (modulus about 2× brass, higher UTS); extreme or chloride corrosion resistance (316 with molybdenum); food-contact, medical or potable duty where austenitic stainless such as 316L is the established, well-understood biocompatible choice for implants and food equipment; high-temperature service; or where magnetic or hygienic wash-down requirements rule brass out. Grade 303 exists precisely because 304 and 316 machine poorly — but even 303 sits well below brass on machinability.
How Brassland fits in
If your part belongs in brass, we machine it in the right grade — free-cutting CW614N or C36000 for high-speed turning, DZR CW602N where dezincification is a risk, or lead-free CW724R / C69300 for potable-water work — using in-house CNC and Swiss turning to ±0.005 mm. We do not machine stainless; if that is what your application needs, specify it and use a stainless shop.
Frequently asked questions
Is brass really easier to machine than stainless steel?
Which is stronger, brass or stainless steel?
For a marine or chloride environment, brass or stainless?
Does brass conduct better than stainless steel?
Is brass cheaper than stainless steel?
Sources & references
Figures on this page are drawn from published alloy datasheets, standards bodies and engineering references. Key sources:
Last reviewed: July 2026. Material and process figures are checked against datasheet and standards references at each review. Cross-material machinability numbers are indicative (see note in the article), not two points on one physical scale.
Need this part in the right alloy?
Brassland machines precision brass, copper and aluminium components to your drawing — Swiss turning to ±0.005 mm, CNC machining in-house, and hot forging through qualified partners. Send a drawing and we will get back to you.
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