Brass Machining and Supply in Jonesboro, AR — C360, C260, Naval Brass

C360 (UNS C36000) is the benchmark free-machining brass alloy — its 100% machinability rating is the reference point against which all other metals are measured. The 61.5% Cu, 35.5% Zn, 3% Pb composition produces short, clean chips at high cutting speeds (300–500 SFM with carbide or HSS), allowing Jonesboro's production turning shops to achieve cycle times on brass fittings and connectors that are simply not replicable in any other metallic alloy. A Jonesboro shop producing 1,000 pieces of a 1/2" hex fitting in C360 can turn the same volume in copper or stainless that would take 3x to 8x the time. Practical applications for C360 in Jonesboro's industrial base include hydraulic fittings, quick-connect bodies, instrument fittings, push-to-connect pneumatic connectors, valve stems, threaded inserts, and electrical terminals. Agricultural equipment OEMs in Northeast Arkansas specify C360 for irrigation system fittings, fertilizer injection ports, and fluid-handling connectors throughout their machinery. Construction equipment supply chains use C360 for pneumatic tool fittings, hydraulic test point couplers, and precision spacers and standoffs in electrical enclosures. C360's lead content (3%) provides the free-machining characteristic but imposes restrictions in some end-use applications. NSF 61 and NSF 372 (lead-free plumbing) compliance requires lead content below 0.25% — C360 does not meet this standard and cannot be used in potable water applications where these certifications are required. For food-grade, potable water, or pharmaceutical equipment fittings, Jonesboro buyers must specify lead-free brass alternatives including C28000 (Muntz metal), bismuth-brass alloys, or lead-free C69300 silicon brass. Always confirm application requirements before defaulting to C360 on fittings that might enter water or food supply contexts.

C260 (UNS C26000, 70% Cu / 30% Zn) is the cartridge brass specification, named for its historical use in ammunition cases that require the combination of excellent cold-formability, corrosion resistance, and moderate strength. For Jonesboro buyers sourcing brass sheet metal components — formed enclosures, electrical contact springs, heat-exchanger fins, shielding panels, and decorative architectural hardware — C260 in annealed or H temper is the standard specification that balances cost, corrosion resistance, and the ability to form without cracking. C260 sheet in H02 (1/2-hard) temper provides 70,000 psi tensile with 25% elongation — enough ductility for moderate forming operations including bending to a 2T radius, shallow drawing, and stamping without annealing between operations. For deeper drawn components, starting with annealed C260 (65,000 psi tensile, 40% elongation) allows more severe reductions per draw pass before intermediate annealing is required. Jonesboro stamping shops process C260 on progressive dies for high-volume electrical contacts, spring clips, and terminal components that combine stamping, forming, and partial cutoff in a single progressive die sequence. Corrosion resistance of C260 in Jonesboro's humid climate is excellent for atmospheric and mild chemical environments. The alloy is susceptible to stress-corrosion cracking (dezincification and SCC) in ammonia-containing environments — a relevant consideration for agricultural equipment components exposed to anhydrous ammonia fertilizer or ammonia-based cleaning compounds. Fully annealing C260 components before use in ammonia-adjacent environments, or specifying aluminum brass (C68700, 76% Cu / 22% Zn / 2% Al) for ammonia-resistant applications, eliminates SCC risk at modest cost premium.

Naval brass (C46400, UNS C46400 — 60% Cu, 39.2% Zn, 0.8% Sn) was developed for seawater service and carries the tin addition that suppresses dezincification — the selective leaching of zinc that weakens standard brass in chloride environments. For Jonesboro equipment buyers whose machinery operates in water treatment, chemical handling, or high-humidity outdoor environments where standard C360 or C260 would dezincify and develop porous, weakened surfaces over time, Naval brass provides the corrosion upgrade that maintains structural and sealing integrity in service. Naval brass is produced in rod, bar, plate, and tube forms. Its machinability at roughly 40% relative to C360 is adequate for moderate-complexity CNC turned parts — valve seats, pump impellers, water-handling fittings — though cycle times are roughly 2.5x longer than equivalent C360 parts. Jonesboro shops running Naval brass budget accordingly and typically charge a machining rate premium of 30–50% over C360 parts of equivalent geometry, in addition to the higher material cost (Naval brass bar runs approximately 30–40% above C360 per pound at regional distributors). For Jonesboro agricultural equipment applications involving irrigation system hardware, water supply fittings, or aquatic environments — rice farming operations in the White River bottoms east of Jonesboro are a relevant example — Naval brass or lead-free architectural bronze provides corrosion life several times greater than C360 in continuous water contact service. Buyers specifying components for potable water irrigation should confirm NSF compliance requirements for their specific regulatory context, as some municipal and state water systems require lead-free certification on all wetted components regardless of alloy designation. Welding Naval brass requires care to avoid zinc fuming (zinc vaporizes at 1,665°F, well below brass melting temperatures in the weld zone). Jonesboro welders handling Naval brass weldments use positive-pressure HEPA-filtered ventilation, lower heat input TIG welding with naval brass filler (ERCuSn-A or ERCuZn-B), and keep torch standoff generous to minimize zinc vapor generation. OSHA permissible exposure limits for zinc oxide fume are 5 mg/m³ (ceiling) — adequate ventilation is not optional when welding zinc-containing alloys.