Brushed Metal Finish for Machined Parts
The directional satin surface that hides fingerprints and gives metal its signature grain — process, Ra, brushed vs polished vs bead blasted, and which metals it suits.
IsoCNC Engineering Team
CNC Machining & DFM Engineers · Updated · 7 min read
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Quick Answer
A brushed finish is a directional satin surface — abrasive media dragged across the metal in one direction leaves a visible linear grain, the classic stainless No. 4 look. It lands around Ra 0.3–1.5 µm, hides fingerprints far better than a mirror polish, and dominates appliances, food equipment, and architectural and automotive trim. Brushed is satin and directional, polished is mirror-smooth, and bead blasted is a uniform matte with no grain.
The Finish That Hides Its Own Fingerprints
Of the three cosmetic metal finishes — brushed, polished, and bead blasted — brushing is the one that combines good looks with practicality. A brushed surface is created by dragging abrasive media across the metal in a single direction, leaving a fine linear grain. That grain is not just decorative: it hides fingerprints, smudges, and light scratches that would scream on a mirror polish. That is why brushed stainless is the default in commercial kitchens, and brushed aluminum is everywhere in consumer electronics and automotive trim. This guide covers what brushing actually is, the Ra it hits, and how it compares to the alternatives.
How Brushing Is Done, and the Ra It Hits
Brushing is a mechanical, directional process — a wire brush, abrasive belt, or Scotch-Brite surface-conditioning pad is moved across the surface in one consistent direction to cut the linear grain. On stainless it produces the familiar No. 4 finish. The result is a satin surface that typically measures Ra 0.3–1.5 µm — with stainless No. 4 around 0.7–1.0 µm (29–40 microinches) and finer dairy-grade variants down to about 0.46–0.79 µm. Because the exact finish depends on grit and pass count, the right way to spec it is a target Ra plus a grain direction, not just the word brushed.
Brushed vs Polished vs Bead Blasted
The three finishes solve different problems:
| Finish | Look | Typical use |
|---|---|---|
| Brushed | Directional satin, visible linear grain | Appliances, food equipment, trim |
| Polished | Smooth, mirror-like | Decorative, high-luster parts |
| Bead blasted | Non-directional matte, no grain | Uniform matte, prep for coating |
The practical tiebreakers: brushed hides fingerprints and small scratches, polished shows every mark but gives the highest luster, and bead blasted gives a uniform matte that carries no grain — useful as a clean base or as prep before anodizing. For the bead-blasting side, see our bead blasting guide.
Which Metals, and Where It Gets Used
Stainless steel and aluminum are the brushed-finish workhorses. Brushed stainless No. 4 covers food equipment, commercial kitchen surfaces, architectural cladding, and handrails. Brushed aluminum appears in consumer electronics, appliance trim, and automotive interior and exterior accents. Copper and brass can also be brushed for a warm decorative grain. The process is the same across metals — what changes is the abrasive and the pressure, softer metals needing a lighter touch to avoid over-cutting.
Dimensions and Cost
Brushing removes only a thin surface layer, so it is not a dimensional operation — but it is not zero, and critical fits should be masked or held out of the brushing step. On cost, brushing is low-to-medium: cheaper than mirror polishing, and roughly similar to or slightly above bead blasting. Some suppliers put it at +5–10% over a base machined finish versus +15–25% for polish, but those are estimates — the real cost driver is how many surfaces need brushing and the required grain direction. For the full Ra chart and what each finish level costs, see our surface finish guide.
FAQ
What is a brushed metal finish?
A brushed finish is a directional satin surface made by dragging abrasive media — a wire brush, abrasive belt, or Scotch-Brite pad — across the metal in one direction, leaving a visible linear grain. It is the classic stainless-steel No. 4 finish. Brushing hides fingerprints and small scratches far better than a polished surface, which is why it dominates appliances, kitchen equipment, and architectural trim.
What Ra does a brushed finish achieve?
Brushed finishes commonly land around Ra 0.3–1.5 µm overall, with stainless No. 4 typically around 0.7–1.0 µm (29–40 microinches) and a finer No. 4 / dairy variant around 0.46–0.79 µm. The exact number depends on the abrasive grit and the number of passes, so specify the Ra target, not just the word brushed.
Brushed vs polished vs bead blasted — which should I choose?
Brushed gives a directional satin grain that hides fingerprints; polished gives a smooth mirror that shows every mark; bead blasted gives a uniform non-directional matte with no grain. Choose brushed for appliances, food equipment, and trim where the linear look and fingerprint resistance matter; polished for high-luster decorative parts; bead blasted for a clean matte or as prep before coating or anodizing.
Which metals can be brushed?
Stainless steel and aluminum are the most common — stainless No. 4 is the workhorse of food equipment and architecture, and brushed aluminum is everywhere in consumer and automotive trim. Copper and brass can also be brushed. The process is the same across metals; the abrasive and pressure are what change.
Does brushing change part dimensions?
Minimally, but not zero — brushing removes only a thin surface layer, so it is not a dimensional process like turning or grinding. Critical fits should be held out of the brushing step or masked. For the full surface-finish Ra picture, see our surface finish guide.
How much does a brushed finish cost?
Brushing is a low-to-medium cost finish — generally cheaper than mirror polishing and roughly similar to or slightly above bead blasting. Some sources put it at roughly +5–10% over a base machined finish versus +15–25% for polishing, but treat those as supplier-dependent estimates, not universal prices. The grain direction and how many surfaces need brushing drive the real cost.
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