Brass Machining & Fabrication Suppliers in Rock Hill, SC: C360, C260 & Naval Brass

Grade C360 (UNS C36000) is the benchmark free-machining brass — its 2.5–3.7% lead content creates discontinuities in the grain structure that cause chips to break into short, uniform segments at high cutting speeds. With a machinability rating of 100 on the standard scale, C360 runs at 500–700 SFM on multi-spindle screw machines, automatic bar feeders, and CNC turning centers with carbide tooling, producing thousands of identical parts per shift with minimal tooling wear and excellent surface finish. This is why Rock Hill shops producing plumbing fittings, push-to-connect valves, hydraulic adapters, and electrical connectors default to C360 bar stock — the economics of high-speed turning with short cycle times and minimal tooling cost per part are unmatched by any other metal. C360 is available in hexagonal, square, and round bar form from Charlotte-area service centers, with hex bar being the standard form for fitting bodies and valve components where hex flats are required on the finished part. Typical sizes run from 1/4" hex through 2.5" hex, with 5/16"–1" being the highest-volume range for plumbing and connector work. The lead content in C360 gives it excellent corrosion resistance in atmospheric and freshwater environments but makes it incompatible with potable water applications in many jurisdictions — California, Vermont, and Maryland restrict lead-containing brass in plumbing that contacts drinking water, and the NSF/ANSI 61 standard for potable water contact specifies alternative grades. For Rock Hill's building products manufacturers supplying low-lead or no-lead plumbing markets, C36000 is being specified less frequently in favor of bismuth-substituted alloys (C89836, C89520) that replicate the machinability of C360 without lead content. These newer alloys carry a modest material cost premium but eliminate lead compliance risk entirely. Some Rock Hill shops now stock both C360 and C89836 for different customer programs.

Grade C260 (70% copper, 30% zinc, UNS C26000) is the forming and drawing brass — its high copper content relative to C360 (60% copper) gives it superior ductility, cold-work response, and springback behavior that makes it the standard for deep-drawn cartridge cases, stamped terminals, shell components, and formed sheet metal parts. The same ductility that makes C260 excellent for forming makes it a poor choice for high-speed machining — it machines at roughly 30–40% of C360's speed and produces long, stringy chips that require frequent clearing. Rock Hill shops that specialize in stamping and progressive die work for automotive connectors and electrical terminal strips use C260 strip and sheet in coil form. C260 in cold-worked tempers (half-hard H02, hard H04, spring H08) develops significant yield strength through work hardening — H04 temper reaches 60–75 ksi yield strength versus 15–20 ksi for annealed. This temper-dependent strength makes C260 the correct specification for spring contacts, clip terminals, and other electrical components that must maintain contact force over thousands of insertion cycles. When specifying C260 for a stamped contact application, the temper designation is as important as the alloy designation — specify both, and confirm the strip supplier can provide the specified temper with the required mechanical property certificate. Formability of C260 is best exploited with proper tooling design: bend radii of 1–2 times material thickness in the H02 temper, increasing to 3–5T in H08, prevent cracking at bends. Rock Hill stamping shops running C260 for automotive electrical connectors design their progressive dies with these bend radius minimums built in, and they test new tooling with pilot runs before committing production quantities.

Naval brass (C46400, 60% copper, 39.25% zinc, 0.75% tin) adds tin to the alpha-beta brass structure, improving resistance to dezincification — the selective leaching of zinc from brass alloys that occurs in certain water chemistries (soft water, slightly acidic water, elevated temperature). Dezincification leaves behind a porous copper sponge that has lost all structural integrity while maintaining the original external dimensions, a dangerous failure mode in pressure-containing applications. Naval brass is the correct specification for marine hardware, heat exchanger tube sheets, and plumbing fittings in recirculating hot water systems where dezincification is a known risk. Inhibited admiralty brass (C44300) takes dezincification resistance further with a higher tin content and arsenic addition that completely inhibits the dezincification mechanism. It appears in heat exchanger tubing for power generation and chemical processing. Rock Hill suppliers serving industrial equipment manufacturers building heat exchangers for process industry applications should be familiar with both Naval brass and C44300 admiralty brass, as the two grades address different severity levels of dezincification risk. The machinability of Naval brass is approximately 40% of C360 — significantly lower than free-cutting brass but much better than copper alone. Surface speeds of 200–300 SFM with carbide tooling produce acceptable results, though chip breaking is less predictable than with C360. For turned components in Naval brass, Rock Hill shops use high-positive-rake tooling and adequate chip-breaking groove geometry to manage the more ductile chip behavior.

Brass's warm golden color is visually appealing for decorative applications, but most industrial brass parts require additional surface treatment for corrosion protection, electrical performance, or regulatory compliance. Electroplated nickel over brass provides a uniform, hard surface (400–600 HV) that resists tarnishing and improves wear resistance on connector contacts and valve seats. Tin plating (bright or matte) is the standard finish for solderability-critical electrical terminals and maintains solderability for 12–24 months under proper storage conditions. Chrome plating over nickel undercoat gives decorative hardware the bright appearance required for architectural and plumbing fixture applications. For high-visibility architectural brass components in Rock Hill's building products sector, clear lacquer coating over buffed or satin-brushed brass maintains the original appearance while slowing tarnish. Antique brass and oil-rubbed bronze chemical finishes are also available for decorative components, applied through controlled chemical treatment processes. All of these finishing operations are available through electroplating and metal finishing shops in the Charlotte metro corridor within 20–30 miles of Rock Hill, with typical 5–10 business day turnaround on production quantities.