Brass Turned Parts
C36000 / C37700 · Ø1–20 mm · nickel, tin and chromate finishing · ±0.005 mm
CHX Metal produces brass turned parts from C36000 and C37700 bar on 70 Tsugami Swiss-type lathes, Ø1–20 mm, held to ±0.005 mm, with nickel, tin, silver or chromate finishing in-house. Monthly capacity is 5 million pieces and a DFM review with price returns in 24 hours.
Brass is the material buyers assume will be easy, and it usually is — until the wall is 0.4 mm, the thread is M1.2, or the plating blisters because the surface was burnished rather than properly prepared. These are the three failure modes that show up in incoming inspection, and each one is preventable at the process stage.
Grades, and why the choice is not cosmetic
| Specification | Capability |
|---|---|
| C36000 free-cutting brass | Highest machinability rating; default for high-volume pins and inserts |
| C37700 hot-die brass | Better hot workability and slightly higher strength; used for forged-then-machined bodies |
| C26000 cartridge brass | Ductile, good for thin-wall drawn or spun parts that need forming after machining |
| C93200 bearing bronze | For bushings and wear parts where lubrication matters more than strength |
| Lead-free options | Available on request for RoHS-sensitive programmes; machinability drops, so the price reflects it |
If the drawing does not name a grade, the shop picks one. That is fine for a bracket and a bad idea for a current-carrying contact, because conductivity and machinability trade off against each other.
Thin walls, small threads and the limits that matter
On brass, the practical floor for a turned wall is around 0.3 mm at Ø6 mm, and it drops as diameter grows. Below that the part deflects under tool pressure and the wall becomes tapered rather than cylindrical — a defect that passes a calliper check and fails on a CMM.
Threads below M1.5 are usually cut on the Swiss cell with a dedicated attachment rather than tapped, because a tap that small snaps and the broken piece costs the whole cycle. If the thread is a locating feature rather than a fastening one, say so in the DFM note: it may be cheaper to bore and press a threaded insert.
Finishing: where brass parts actually fail
- Blisters after nickel plating — caused by residual cutting oil or by a burnished rather than clean surface; the fix is an ultrasonic pre-clean and a controlled rinse.
- Tarnish in transit — brass oxidises; chromate or a thin benzotriazole film buys months, and it costs a fraction of a rework shipment.
- Thread damage in bulk packing — parts that touch in a bag will gall; tray packing or a media separator is a cheaper decision than a sorting operation at the customer.
- Dimensional shift after plating — a 5 µm nickel deposit moves a ±0.005 mm feature by 40% of its tolerance; the pre-plate dimension has to be set deliberately.
Where brass turned parts are used
Electrical contacts and terminals, RF connector bodies, valve stems and fittings, watch and instrument parts, camera and optical mounts, plumbing cartridges, threaded inserts for plastics, and decorative hardware. The common thread is a need for conductivity, corrosion resistance or a machined surface that takes plating well.
Volume pricing, honestly
Bar stock is priced by weight and brass carries a copper surcharge that moves. A quote given today may not hold in six weeks unless the supplier states its validity and the surcharge basis. We quote with the LME copper basis named, so the number can be checked rather than trusted.
Related capabilities
CNC turned parts manufacturer · Turning: aluminium, stainless, brass · Stainless steel turned parts · Surface treatment · Swiss-type CNC turning · CNC machining China
Request a quote
Send drawing (STEP / PDF / DXF) with material, tolerance and annual volume to mc@chxmetal.com. DFM feedback and a price within 24 hours, NDA on request.
Get a CNC quote · Contact CHX Metal · Supplier profile & certificates
Frequently asked questions
Which brass grade do you machine most?
C36000 free-cutting brass, because it machines fastest and holds a clean thread. C37700 is used where the part is hot-formed before machining, and C26000 where the part must be formed after turning.
Can you supply lead-free brass?
Yes, on request for RoHS-sensitive programmes. Machinability is lower than C36000 so the unit price is higher; the DFM note states the difference before you commit.
What is the minimum wall thickness for a brass turned part?
Around 0.3 mm at Ø6 mm, increasing with diameter. Below that the wall deflects under tool pressure and tapers, which a calliper will not catch but a CMM will.
Do you do nickel, tin and silver plating on brass?
Yes — nickel, tin, silver and chromate conversion coatings, 3 to 7 days. Pre-plate dimensions are set deliberately because a 5 µm deposit consumes 40% of a ±0.005 mm tolerance.
What volume can you run?
One piece to millions. Monthly plant capacity is 5 million pieces across all materials, and brass runs are typically the fastest because the material machines freely.