C260 cartridge brass CNC machining serves parts that must bend, crimp, flare or swage after they leave the machine. C260 is a 70/30 copper zinc alloy with no added lead, so it is far more ductile than free-cutting brass. The name comes from its long use in drawn ammunition cases. Wexmar turns and mills C260 in Canastota, New York for connector, hardware and fluid handling customers who need that formability in a precision machined part.
Machinability of C260
On the copper-alloy machinability scale, where free-cutting C360 is the reference at 100, C260 rates about 30. That is a large drop. Without lead to break the chip, C260 forms long, continuous, gummy chips and tends to smear rather than shear cleanly. It is still readily machinable, but cycle times are longer and chip control drives the process more than in C360.
Tolerances and surface finish
Typical tolerances on precision C260 turned parts are plus or minus 0.001 in on diameters and lengths, with plus or minus 0.0005 in achievable on selected features once the process is stable. A 32 to 63 Ra finish is typical, depending on tooling and feature. Because the alloy is soft and ductile, thin sections can deflect under cutting load, so finish passes are kept light. These are typical values, not guarantees.
C260 machining gotchas
- Stringy chips. Long ribbons wrap tools and parts. We use sharp, high positive rake geometry with chip breakers, higher feed where finish allows, and high pressure coolant to break and clear chips.
- Burrs. C260 throws heavier burrs than C360 at thread starts, cross holes and part-off. Deburring is planned into the cycle with live tools rather than left to hand work.
- Drilling. Chips pack in deep holes. Peck cycles, polished flutes and good coolant flow keep holes round and drills intact.
- Work hardening from forming. The alloy hardens as it is cold worked. If a part will be crimped or flared after machining, the temper of the bar matters, and a soft temper or an anneal may be specified.
- Season cracking. High zinc brass under residual stress can crack in ammonia bearing environments. A stress relief anneal after forming reduces that risk.
Annealing and finish options
Stress relief and annealing are handled through qualified outside processors, as are plating and surface finishes. Common finishes for C260 include nickel, tin and silver plating, bright dipping and clear lacquer. Where a part is formed after machining, we coordinate whether plating happens before or after forming so the coating does not crack.
Common C260 parts and which process fits
- Crimp ferrules and terminal barrels for electrical and connector assemblies
- Sleeves and tubing ends that are swaged, flared or rolled after machining
- Eyelets, grommets and spacers for hardware and instrumentation
- Decorative and architectural hardware where C260 color and polish are preferred
- Heat exchanger and radiator fittings
Small diameter C260 parts up to 32 mm run on our Swiss-type machines, where the guide bushing supports long, slender parts that would otherwise deflect. Larger diameters and parts with milled flats or cross holes run on our CNC lathes with live tooling.
Cost index: C260 vs related materials
| Material | Approx. machinability | Cost index vs 6061 | Notes |
|---|---|---|---|
| 6061-T6 aluminum | ~180 (1212 scale) | 1.0 | Reference for cost |
| C360 free-cutting brass | 100 (copper scale) | 1.2 | Leaded, fast cutting |
| C260 cartridge brass | 30 (copper scale) | 1.6 | Unleaded, formable |
| C954 aluminum bronze | 50 (copper scale) | 2.0 | High strength bronze |
| C110 copper | 20 (copper scale) | 2.2 | Highest conductivity |
| 1018 cold drawn steel | ~78 (1212 scale) | 1.1 | Low cost where plating is acceptable |
These figures are typical and illustrative for a comparable part; actual quotes depend on geometry, quantity, tolerances and mill pricing, and brass cost follows the copper market.
Applications and industries
C260 cartridge brass machining services support electrical and connector makers, instrumentation builders, lighting and hardware manufacturers, and fluid handling OEMs. It is chosen over C360 when the part must be formed, when a lead-free copper alloy is needed for regulatory reasons, or when bright color and polish matter. If the part is never formed after machining, the C360 brass machining page covers the faster, lower cost option. Material certs and lot traceability are available for C260 orders shipped from our Central New York shop.
Getting a quote
To price C260 parts, upload a drawing for an instant estimate or call (315) 400-2654. A human estimator confirms every quote, including temper, finish and any forming allowances.