Copper Machining, Fabrication & Supply in York, PA

Three copper grades drive the majority of industrial machining and fabrication demand in the York region. C101 oxygen-free electronic copper (OFE, UNS C10100) is the ultra-high-purity grade — 99.99% copper minimum, no oxygen — specified for semiconductor bonding wire, high-vacuum components, and applications where hydrogen embrittlement from oxygen-bearing copper in reducing atmospheres is a reliability concern. It is less common in general industrial machining but available from specialty distributors serving the region's electronics and defense-adjacent accounts. C110 electrolytic tough pitch copper (ETP, UNS C11000) is the industry standard — 99.9% copper, 0.02–0.04% oxygen, excellent electrical conductivity (100% IACS), widely stocked in bar, plate, tube, and sheet. C110 is the default choice for bus bars, electrical connectors, heat sinks, and formed copper components where conductivity and cost-efficiency drive specification. York fabricators who work with HVAC, power distribution, and industrial equipment OEMs run C110 routinely. Tellurium copper (C14500, UNS C14500) adds 0.4–0.7% tellurium to improve machinability dramatically — from a machinability rating of approximately 20% for C110 to 90% relative to free-machining brass. The tellurium addition creates short, discontinuous chips rather than the long stringy chips that characterize C110 turning and cause tool wrapping. Conductivity drops only modestly (93–95% IACS), making tellurium copper the correct specification for precision-machined electrical connectors, terminals, and contact components where turning and drilling must be done at production rates.

Copper's machinability challenges differ fundamentally from steel or aluminum. Pure copper and C110 are extremely ductile and produce long, stringy chips that wrap around tooling and workpieces if chip geometry is not managed. Proper machining of C110 requires sharp tooling (minimum 10° positive rake), high surface speeds (300–600 SFM for carbide turning), and aggressive feed rates to promote chip breakage. Flood coolant or cutting oil reduces built-up edge on the tool face — copper's tendency to weld to tooling at elevated temperature is the primary cause of poor surface finish on copper-turned parts. Tellurium copper (C14500) solves the chip problem at the cost of slightly reduced conductivity — it runs like brass, produces clean broken chips, and achieves 32 Ra or better surface finish routinely at production feed rates. York CNC shops that produce electrical connector components in volume recommend C14500 specification over C110 for any turned part with small features, cross holes, or close tolerances. The machinability advantage translates directly to lower per-piece cost and more predictable first-article dimensional results. Brass tooling — drills, reamers, taps — used on copper work must be verified for compatibility. Standard high-speed steel taps produce acceptable threads in C14500; C110 often requires spiral-point (gun) taps to manage the long chip during through-hole tapping. For precision bore features, single-point boring is preferred over reamers, which tend to burnish rather than cut in soft copper alloys.