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Brass Grades Comparison for Precision Machining: Choosing the Right Alloy for Your Parts

Posted on by Franky Nguyen

By Franky Nguyen, AVF Decolletage

Introduction

Brass remains one of the most essential materials in precision machining. Its unique combination of electrical conductivity, fluid chip control, corrosion resistance, and smooth surface finish makes it ideal for:

  • Connector pins & sockets

  • Electrical terminals

  • Test probes

  • Micro-precision components

  • Bushings and sliding parts

  • High-volume turned parts

  • RF connectors

  • Medical and telecom components

At AVF Decolletage, brass is one of our core specialties — we run brass parts daily across our Swiss-type CNC lathes, multi-spindle screw machines, and automatic lathes.

Because brass is not “one material,” choosing the wrong grade can affect:

✔ Machinability
✔ Tool life
✔ Conductivity
✔ Mechanical strength
✔ Cost per piece
✔ Dimensional stability
✔ Stress-relaxation performance

This extended guide compares every brass alloy listed in your material slide:

C11000, C14500, C17300, C18200, C18700, C19100, C34000, C35300, C36000, C38500, C54400, C66100

Our goal is simple:
Help engineers, buyers, and designers choose the exact brass alloy that fits their performance and cost requirements.

Brass grades C11000–C66100 machined by AVF Decolletage for connectors and precision CNC components.
Brass alloys for high-precision CNC machining.

1. High-Conductivity Brasses

For electrical connectors, RF pins, and current-carrying components

High-conductivity copper alloys are used when electrical performance is the main requirement. These materials maintain stable conductivity, low resistance, and high thermal transfer.

⭐ C11000 – Electrolytic Tough Pitch Copper (ETP Copper)

Conductivity: ★★★★★ (≈100% IACS)
Machinability: ★★☆☆☆
Strength: ★★☆☆☆
Cost: Moderate

Overview

C11000 is the highest-conductivity material on the list — nearly the same as pure copper. It is soft, ductile, and excellent for electrical transmission.

However, because of its softness and tendency to produce long stringy chips, it can be challenging to machine on Swiss-type lathes, especially for small intricate parts.

Applications

  • High-power electrical contacts

  • Current-carrying terminals

  • Grounding components

  • Busbars

  • Power distribution components

Use C11000 when:

Electrical performance outweighs machining efficiency.

⭐ C14500 – Tellurium Copper

Conductivity: ★★★★★
Machinability: ★★★★☆
Strength: ★★★☆☆
Cost: Moderate

Overview

C14500 is often considered the ideal balance between conductivity and machinability. Adding tellurium transforms this alloy into one that behaves much more predictably on a Swiss lathe.

C14500 creates clean chips, reduces tool wear, and maintains excellent electrical performance.

Applications

  • RF connectors

  • Telecom pins

  • Electronic contacts

  • High-frequency connectors

  • Precision electrical components

Use C14500 when:

You need both conductivity and clean, accurate machining.

⭐ C19100 – High-Strength Conductive Alloy (Spinodal Copper)

Conductivity: ★★★★☆
Machinability: ★★★☆☆
Strength: ★★★★☆
Cost: High

Overview

C19100 is used in high-reliability connectors, especially where operating conditions are harsh — high temperatures, vibration, cyclical loading, and long-term stress.

It holds its shape exceptionally well thanks to its low stress-relaxation behavior.

Applications

  • Miniature connectors

  • Military-grade contacts

  • Aerospace terminals

  • High-flexibility electrical components

Use C19100 when:

You need conductivity + strength + reliability in small dimensions.

2. Free-Cutting Brasses

Best for high-volume machining, lowest cycle time, best cost per piece

These alloys excel in automatic lathe production, especially for connector pins, sockets, and micro-components.

⭐ C34000 – Lead-Free Brass

Machinability: ★★★★☆
Compliance: RoHS + Eco-friendly
Strength: ★★★☆☆
Conductivity: ★★★☆☆

Overview

C34000 is the go-to material when customers require lead-free or RoHS compliance. It is easier to machine than C11000 and maintains good strength and stability.

Applications

  • Medical devices

  • EU-compliant connectors

  • Green/lead-free products

  • Optical sensors

Use C34000 when:

Your customer requires low-lead or lead-free compliance.

⭐ C35300 – High-Strength Free-Cutting Brass

Machinability: ★★★★☆
Strength: ★★★★☆
Conductivity: ★★★☆☆

Overview

C35300 offers better strength than the standard free-cutting C36000, making it ideal when you need:

  • Higher torque strength

  • Better thread performance

  • Better wear characteristics

Applications

  • Precision couplings

  • Higher-strength fittings

  • Connectors with torque-load requirements

Use C35300 when:

You need a stronger alternative to C36000 without sacrificing machinability.

⭐ C36000 – Free-Cutting Brass (THE Industry Standard)

Machinability: ★★★★★ (Best of all alloys)
Strength: ★★★☆☆
Conductivity: ★★★☆☆
Cost: Very cost-effective

Overview

C36000 is the king of machinability. It is the fastest-machining metal in the world.
For Swiss CNC turned parts, it offers:

  • Perfect chip breaking

  • Excellent surface finish

  • Very low tool wear

  • Tight tolerance stability

  • Ideal cycle time optimization

This alloy is the backbone of the connector manufacturing industry.

Applications

  • Connector pins

  • Sockets

  • Terminals

  • Bushings

  • Inserts

  • Test probes

  • High-volume turned parts

Use C36000 when:

You need the fastest machining, lowest cost, and highest volume efficiency.

⭐ C38500 – Architectural Brass

Machinability: ★★★☆☆
Strength: ★★★☆☆

Overview

This alloy is used more commonly for larger components and plumbing fittings. It offers decent machining characteristics but is not typically preferred for micro-precision connectors.

Applications

  • Valves

  • Hose fittings

  • Decorative hardware

Use C38500 when:

The part is moderate in size and does not require ultra-tight tolerances.

3. High-Strength & Spring-Performance Brasses

Best for sockets, spring contacts, aerospace connectors, flexible terminals

⭐ C17300 – Beryllium Copper (BeCu)

Strength: ★★★★★ (Steel-like)
Conductivity: ★★★★☆
Machinability: ★★★☆☆
Cost: High

Overview

C17300 is one of the highest-strength copper alloys available. After heat treatment, it achieves mechanical strength close to tool steels — while still maintaining excellent electrical properties.

Applications

  • Aerospace-grade connectors

  • High-end test probes

  • Socket contacts

  • Spring connectors

  • Medical devices

Use C17300 when:

You need strength + conductivity + fatigue resistance.

⭐ C18200 – Chromium Copper

Strength: ★★★★☆
Conductivity: ★★★☆☆
Wear Resistance: ★★★★☆

Overview

C18200 excels when the part must withstand heat and wear. It is commonly used in heavy electrical or industrial applications.

Applications

  • Power distribution terminals

  • Welding electrodes

  • Heavy-load connectors

Use C18200 when:

Heat resistance and durability are key requirements.

⭐ C18700 – Arsenical Copper

Strength: ★★★★☆
Corrosion Resistance: ★★★★☆

Overview

C18700 is corrosion-resistant and stronger than standard copper — ideal for harsh environments or components exposed to repetitive mechanical stress.

Applications

  • Switchgear components

  • Electrical terminals

  • Corrosive environments

Use C18700 when:

The part must survive outdoor or industrial environments.

⭐ C54400 – Phosphor Bronze

Spring Properties: ★★★★★
Fatigue Resistance: ★★★★☆
Strength: ★★★★☆

Overview

C54400 is the preferred material for spring contacts and socket components.

Its elasticity and wear resistance make it ideal for electrical components that require:

  • Repeated insertion/extraction

  • Contact flexibility

  • Long-term stability

Applications

  • Spring contacts

  • Sockets

  • Flexible terminals

Use C54400 when:

You need a brass grade with actual spring behavior.

⭐ C66100 – High-Lead Tin Bronze

Machinability: ★★★★☆
Wear Resistance: ★★★★☆
Friction: Low

Overview

This alloy is preferred for components that move, slide, rotate, or experience friction.

Applications

  • Bushings

  • Bearings

  • Sliding components

  • Wear pads

Use C66100 when:

The part must withstand friction or rotational wear.

4. Full Brass Comparison Table

Grade Conductivity Machinability Strength Best Use
C11000 ★★★★★ ★★☆☆☆ ★★☆☆☆ High-current contacts
C14500 ★★★★★ ★★★★☆ ★★★☆☆ RF & telecom pins
C19100 ★★★★☆ ★★★☆☆ ★★★★☆ High-reliability connectors
C34000 ★★★☆☆ ★★★★☆ ★★★☆☆ Lead-free components
C35300 ★★★☆☆ ★★★★☆ ★★★★☆ High-strength precision parts
C36000 ★★★☆☆ ★★★★★ ★★★☆☆ Connector pins & sockets
C38500 ★★☆☆☆ ★★★☆☆ ★★★☆☆ Valves & fittings
C17300 ★★★★☆ ★★★☆☆ ★★★★★ Aerospace connectors
C18200 ★★★☆☆ ★★★☆☆ ★★★★☆ High-temp terminals
C18700 ★★☆☆☆ ★★★☆☆ ★★★★☆ Heavy-duty terminals
C54400 ★★☆☆☆ ★★★☆☆ ★★★★☆ Spring contacts
C66100 ★★☆☆☆ ★★★★☆ ★★★★☆ Bearings & sliding parts

6. Q&A Section

Q1: What is the best brass for fast, high-volume machining?

C36000 — unmatched machinability and cost efficiency.

Q2: Which brass should I use for electrical conductivity?

C11000 or C14500.

Q3: Which alloy provides the highest strength?

C17300 (Beryllium Copper).

Q4: Which brass is lead-free or RoHS compliant?

C34000.

Q5: Which brass is best for spring parts?

C54400 (Phosphor Bronze).