Brass CZ 121 Machined Components, Brass CZ 121 Turned Parts

Overview: Brass CZ 121 Machined Components and Brass CZ 121 Turned Parts

Brass & Copper Parts manufactures precision CZ 121 brass machined components and CZ 121 turned parts from its ISO 9001:2015 certified facility in Jamnagar, India. CZ 121 is the BS (British Standard) designation for free-cutting leaded brass rod and bar, equivalent to CW614N under the current EN (European Norm) designation system, and broadly equivalent to ASTM C36000 (CDA 360) in the US and IS 319 Type-I in India. With a nominal composition of CuZn39Pb3 (57–59% Cu, balance Zn, 2.5–3.5% Pb), CZ 121 is the standard material for the majority of brass CNC turned parts, screw machine components, and precision fittings manufactured and exported from the UK, Commonwealth countries, and legacy British Standard specifications. We have 29+ years of experience machining CZ 121 / CW614N / C36000 brass into close-tolerance turned parts, threaded components, valve bodies, fittings, and electronic connector parts for export to OEM buyers in the UK, Europe, USA, Australia, and the Middle East.

What is CZ 121 Brass?

CZ 121 is a British Standard designation for free-cutting brass rod and bar formerly specified under BS 2874. The “CZ” prefix indicates a copper-zinc alloy; “121” identifies the specific grade within the BS 2874 series of copper and copper alloy rods and bars. The alloy is a leaded alpha-beta brass with CuZn39Pb3 nominal composition—39% zinc and 3% lead in a copper matrix. Lead exists as insoluble globules within the brass matrix, acting as internal chip-breakers during high-speed machining, giving CZ 121 a machinability index of approximately 100 (equivalent to the CDA benchmark). BS 2874 has been largely superseded by the current EN 12164 (cold drawn rods) and EN 12165 (extruded rods and sections) standards, which designate this alloy as CW614N (CuZn39Pb3). However, CZ 121 remains widely specified in British-origin engineering drawings, procurement specifications, and legacy product standards, and we accept and supply to CZ 121 specification on request, supplying material certified to EN 12164 / CW614N as the current equivalent.

Key Features of CZ 121 Brass Machined Components

• Machinability Index ~100: CZ 121 (CuZn39Pb3 / CW614N) delivers benchmark free-machining performance equivalent to ASTM C36000, enabling maximum spindle speeds and production rates in CNC turning and screw machine operations.
• Excellent Surface Finish: Short, broken chips from the lead addition produce burr-free turned surfaces with Ra as low as 0.4 µm in finish-turning, reducing post-machining polishing requirements.
• Close Tolerance Capability: Dimensional tolerances to ±0.005 mm on CNC turned diameters; thread class 6H/6g (ISO) or 2A/2B (ANSI) as standard.
• Comprehensive Thread Forms: BSP (ISO 7/1), NPT (ASME B1.20.1), BSPt (BS 21), BSF, BA, metric, UNC, UNF threads all achievable in CZ 121 with clean thread form and minimal tool wear.
• Corrosion Resistance: Suitable for fresh water (non-potable/general service), petroleum products, industrial gases, and atmospheric exposure. Not suitable for ammonia, moist ammonia environments, or continuous seawater immersion (risk of season cracking and dezincification).
• Electrical Properties: Electrical conductivity 26% IACS; suitable for electrical terminal bodies, contact pins, and connector housings.
• Broad Material Form Availability: CZ 121 / CW614N is available as cold-drawn rod (EN 12164), extruded bar (EN 12165), flat bar, and section in a wide range of diameters and profiles from UK and Indian certified mills.

Technical Specifications: CZ 121 / CW614N Brass

CZ 121 International Grade Equivalents Table

CZ 121 Dimensional Tolerances for Rod and Bar

Product Types and Variants

CZ 121 Brass CNC Turned Components

Precision CNC turned parts in CZ 121 / CW614N brass are the core of our British-specification brass machining capability. Using single-spindle and twin-spindle CNC turning centres with live tooling, we produce shafts, spacers, bushings, nipples, couplings, studs, and custom rotational components to close tolerances. Bar diameters from 6 mm to 100 mm are processed; turned diameters are held to ±0.005 mm with roundness within 0.003 mm TIR. Components are supplied to BS, EN, or customer engineering drawings with complete dimensional reports and EN 10204 3.1 MTCs referencing CW614N / CZ 121 composition.

CZ 121 Brass Screw Machine Turned Parts

Multi-spindle and Swiss-type screw machines process CZ 121 bar stock for high-volume production of small turned parts with simultaneous cross-drilling, threading, knurling, and parting operations. CZ 121’s machinability index of ~100 makes it ideal for unmanned high-speed screw machine runs producing electrical terminals, pneumatic nipples, instrument connectors, plumbing components, and automotive fasteners in quantities from 10,000 to several million pieces. Tolerances of ±0.01 mm are held across all spindle positions; SPC data and Cpk values are reported per production lot.

CZ 121 Brass Threaded Parts and Fittings

Threaded fittings, adapters, couplings, and nipples in CZ 121 brass are produced for BSP (BS 21 / ISO 7/1), NPT (ANSI B2.1 / ASME B1.20.1), BSF, BSW, BA, metric, and UNC/UNF thread forms. CZ 121’s low shear strength and lead-assisted chip breaking produce clean, accurate threads with minimal torn thread surface. Thread class 6H/6g ISO or 2A/2B ANSI is standard; tighter class 3A/3B available on CNC precision turning. Go/No-Go thread gauges (traceable to NPL) are used on 100% of critical threaded features.

CZ 121 Brass Valve and Plumbing Components

CZ 121 brass valve bodies, gate valve stems, needle valve seats, check valve housings, and plumbing fittings are machined for general water service (non-potable), gas service, industrial fluid systems, and pneumatic applications. For potable water in the UK and EU, DZR or lead-free alloys are required; CZ 121 is suitable for general industrial water, hydraulic oil, lubricant, and gas service. Bore concentricity, seat angle accuracy (±0.25°), and hydrostatic pressure testing (at 1.5× PN rating) are standard quality requirements for valve components.

CZ 121 Brass Electrical and Electronic Components

Electrical terminal pins, connector bodies, bus bar studs, relay armature pins, and switch contact bodies in CZ 121 brass are produced for electrical switchgear, industrial connectors, and telecom infrastructure applications. CZ 121’s 26% IACS electrical conductivity is adequate for terminal bodies and connector housings; tin or nickel plating provides contact surface protection. Components comply with IEC 60947, BS EN 60947, and NEMA connector standards. Note: for RoHS 2 compliance, CZ 121’s Pb content (2.5–3.5%) requires RoHS Annex III Category 6(c) exemption for copper alloys.

CZ 121 Brass Precision Ground and Polished Components

Where extremely tight dimensional tolerances or superior surface finish are required beyond CNC turning capability, CZ 121 brass parts are centreless-ground or cylindrically-ground after turning. Centreless grinding achieves diameter tolerances of ±0.002 mm and roundness within 0.001 mm TIR with Ra surface finish to 0.2 µm. These precision ground CZ 121 components are used in valve stem guides, hydraulic spool valve components, precision gauging pins, and bearing journals where interference or clearance fits are critical.

Applications by Industry

Manufacturing Process for CZ 121 / CW614N Turned Parts

Step 1 – Material Receipt and Verification: CW614N (CZ 121) rod or bar is received from EN 12164/12165 certified mills with EN 10204 3.1 MTCs. Incoming XRF analysis confirms Cu, Zn, and Pb content compliance to CW614N specification. Bar diameter and straightness are verified against EN 12164 tolerance class requirements.

Step 2 – Toolroom Preparation: CNC turning programs are loaded and verified on the machine controller. Tool offsets are established and a first-off part is machined and fully inspected before production approval. For screw machine work, cam profiles or CNC servo programs are verified with first-off samples.

Step 3 – CNC Turning or Screw Machine Production: Bar stock is fed through the collet or bar-feeder. CZ 121’s machinability allows high cutting speeds (200–300 m/min turning) with minimal coolant usage due to the lead’s internal lubrication. Short, broken chips are produced, falling away cleanly from the cutting zone.

Step 4 – Live Tooling Operations: Cross-drilling, milling of flats, slotting, and radial hole operations are performed using live tooling stations on CNC turning centres, eliminating secondary machining operations and datum errors from re-clamping.

Step 5 – Thread Production and Gauging: Threading is performed by single-point thread turning, thread rolling, or tapping, depending on thread class and volume. Go/No-Go gauges verify all threaded features. Thread gauges are calibrated to NPL/NIST traceability.

Step 6 – Deburring, Cleaning, and Finishing: Vibratory tumbling removes machining burrs. Ultrasonic alkaline cleaning removes coolant residue. Optional barrel polishing achieves Ra 0.4–0.8 µm finish. Passivation or lacquering prevents tarnishing during transit.

Step 7 – Final Inspection: CMM dimensional inspection, surface roughness measurement, thread gauging, and visual inspection per AQL 1.0 (critical) / 2.5 (major). SPC Cpk ≥ 1.33 is required for production release. Full dimensional report issued per lot.

Step 8 – Packing and Export: Parts are packed in compartmentalized polythene bags, foam trays, or bulk cartons with desiccant. Export documentation includes EN 10204 3.1 MTC (CW614N / CZ 121), inspection report, packing list, commercial invoice, and Certificate of Origin (India).

Quality Standards and Certifications

• ISO 9001:2015 Certified Quality Management System
• Material certification to EN 12164 (CW614N cold drawn rod) or EN 12165 (extruded bar); BS 2874 CZ 121 historical reference provided on request
• EN 10204 Type 3.1 material test certificate with stated composition and mechanical properties
• Thread gauging per BS 21 (BSPt), ISO 7/1 (BSP), ISO 965 (Metric), ASME B1.20.1 (NPT), BS 1580 (BA)
• Dimensional inspection per BS 8888 / ISO 1101 GD&T requirements
• SPC-controlled production with Cpk ≥ 1.33 on critical dimensions
• RoHS 2 Annex III Category 6(c) exemption for lead in copper alloys (Pb 2.5–3.5%)
• REACH SVHC declaration (lead is SVHC; exemption applies for copper alloys above 4% Cu threshold)
• PPAP Level 1–3 available on request for automotive or OEM procurement

Why Choose Brass & Copper Parts for CZ 121 / CW614N Turned Parts

• CZ 121 Specification Expertise: Our team works with BS legacy designations and can cross-reference CZ 121 drawings to current EN 12164 / CW614N material with full equivalency documentation.
• Jamnagar Production Advantage: Located in India’s brass precision machining capital; direct access to EN 12164 CW614N certified bar stock from accredited Indian and European mills.
• Comprehensive Thread Competency: BSP, BSPt, BSF, BSW, BA, UNC, UNF, metric, and NPT threads all produced in-house with calibrated gauging; the full range of historical British thread standards is supported.
• Volume and Mix Capability: From 100-piece prototype batches on CNC turning centres to multi-million piece annual volumes on multi-spindle screw machines.
• Documentation for UK Market: EN 10204 3.1 MTC, BS cross-reference certification, RoHS exemption documentation, and UK import compliance records provided as standard.
• Cost-Effective Supply: 25–40% cost saving versus UK domestic brass machining for equivalent quality, with 4–6 week lead time and express freight options.

Frequently Asked Questions

Is CZ 121 still a current standard?

BS 2874 (which included CZ 121) has been withdrawn and largely superseded by the EN 12164 and EN 12165 standards, which designate the same alloy as CW614N (CuZn39Pb3). We supply material to EN 12164 / CW614N specification, which is the current equivalent of CZ 121, and can include CZ 121 cross-reference on material certificates for legacy drawing compliance.

What is the difference between CZ 121 and CZ 120?

CZ 121 contains 2.5–3.5% Pb (free-machining grade); CZ 120 (now CW612N, CuZn39Pb2) contains 1.5–2.5% Pb and has a slightly lower machinability index (~80). CZ 121 is preferred for high-speed screw machine work; CZ 120 is used where lower lead content is desired without switching to lead-free alloys.

Is CZ 121 the same as C36000?

CZ 121 (CW614N, CuZn39Pb3) and ASTM C36000 are very similar free-machining brass alloys with comparable machinability indices. The main difference is copper content: CZ 121 / CW614N has 57–59% Cu; C36000 has 60–63% Cu. Both achieve machinability index ~100. For practical machining purposes, they are functionally equivalent, though material certification must reference the correct standard for the applicable engineering specification.

Can you supply material to CZ 121 with a BS 2874 reference on the MTC?

Yes. We can supply EN 12164 CW614N material with a cross-reference note to CZ 121 / BS 2874 on the material test certificate. The composition and properties are equivalent; the current material specification is EN 12164 / CW614N, and we document the historical BS cross-reference for legacy drawing compliance.

What thread gauges do you use for BSP and BSPt threads?

We use calibrated Go/No-Go thread gauges traceable to NPL (National Physical Laboratory, UK) for BSP (per ISO 7/1), BSPt (per BS 21 / EN 10226-1), and BSF/BSW threads. Gauge calibration certificates are available for customer QA review.

What is the typical dimensional tolerance on CZ 121 turned parts?

Standard CNC turning: ±0.01 mm diameter, ±0.02 mm length. Precision turning: ±0.005 mm diameter, ±0.01 mm length. Centreless grinding after turning: ±0.002 mm diameter, roundness within 0.001 mm TIR. Thread class: 6H/6g (ISO) or 2A/2B (ANSI) standard; 3A/3B on precision parts.

What is your minimum order quantity for CZ 121 machined parts?

Prototype CNC turned parts: from 50 pieces. Production CNC turned parts: from 500 pieces. Multi-spindle screw machine: from 10,000 pieces. No NRE (non-recurring engineering) charge for standard cylindrical turned parts; tooling charges apply for form tools and special drilling fixtures.

Can you supply CZ 121 brass parts with nickel plating?

Yes. Electroless nickel (per MIL-C-26074 / EN ISO 4527), bright electrolytic nickel, and other platings are available through our approved plating partners. Plating thickness is verified by XRF coating gauge and reported on the batch certificate.

Is CZ 121 suitable for potable water in the UK?

CZ 121’s lead content (2.5–3.5%) means it does not meet WRAS requirements for potable water contact components in the UK. For UK potable water applications, DZR brass (CW602N / CZ 132, tested per BS EN ISO 6509) is required. We supply both CZ 121 (for general service) and DZR brass (for potable water) and can advise on the appropriate material for your application.

Do you provide first article inspection reports for CZ 121 turned parts?

Yes. First article inspection reports (FAIR) are produced for all new part numbers, including a complete dimensional check against the engineering drawing, surface finish measurement, thread gauge verification, and visual inspection. FAIRs are issued before production approval and provided to customers on request.

Request a Quote for Brass CZ 121 / CW614N Machined Parts

Submit your engineering drawings (DXF, STEP, PDF), specify CZ 121 or CW614N alloy, thread standards (BSP, NPT, metric), quantity, and lead time requirements. Our technical team will cross-reference your BS specification to the current EN equivalent and provide a competitive quotation with full compliance documentation within 24–48 hours.

Email: sales@brass-copper-parts.com | Phone/WhatsApp: +91-22-43449300

Brass & Copper Parts (India) – Plot 10-B, GIDC Industrial Estate, Shankar Tekri, Jamnagar 361004, Gujarat, India.