Brass CNC Machining: C360 vs H62 vs H65 Selection Guide

Brass is one of the most widely used materials for brass CNC machining thanks to its excellent machinability, corrosion resistance, and electrical conductivity. However, simply specifying "brass" on a drawing can lead to costly mismatches in performance, cost, and compliance across global supply chains.

Different brass alloys deliver drastically different results in chip control, surface finish, and mechanical strength. For engineers and procurement teams, choosing the right grade directly impacts production yield, tool life, and final part functionality.

This guide breaks down three of the most commonly specified grades - C36000 brass, H62 brass, and H65 brass - plus related alloy families, to help you make accurate, cost-effective material decisions.

Free-cutting brasses are the workhorses of high-volume brass CNC turning and screw machine production. They contain controlled levels of lead that act as a lubricant during cutting, resulting in short, broken chips and minimal tool wear.

Core Composition and Machinability
The brass machinability rating of C36000 is set as the 100% benchmark against which all other metals are measured. This grade delivers consistent chip breaking even at high spindle speeds, making it ideal for complex, tight-tolerance parts.

Typical Applications
Free-cutting brasses are the first choice for high-volume brass screw machine parts, threaded components, and electrical connectors. They are also widely used for brass valve bodies where dimensional consistency and leak-tight threads are critical.

For projects requiring fast turnaround and low per-part cost, this family delivers the best overall machining economy.

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Structural and marine brasses balance higher strength with good corrosion resistance, making them suitable for load-bearing and outdoor or saltwater-exposed parts. They fall into the alpha-beta (duplex) brass category, which gives them improved mechanical properties over pure alpha grades.

H62 Brass Properties and Performance
H62 brass, also known as C28000 Muntz Metal in US standards, contains approximately 62% copper and 38% zinc. It offers higher tensile strength than free-cutting grades but has a lower machinability rating due to reduced lead content.

This grade is commonly used for structural brackets, fasteners, and general-purpose hardware where strength takes priority over maximum machining speed.

Naval Brass C46400 for Corrosion Resistance
Naval Brass C46400 adds tin to the alloy composition, significantly improving resistance to saltwater corrosion and dezincification. It is the go-to choice for marine brass hardware, shipboard components, and coastal infrastructure parts.

While naval brass machines well, it produces longer, more stringy chips compared to C36000, so tool geometry and chip breaker design must be adjusted accordingly.

For marine and offshore projects, working with a supplier experienced in marine CNC machined parts ensures proper material certification and corrosion performance.

Cold forming brasses are highly ductile alpha-phase alloys designed for post-machining forming operations such as stamping, deep drawing, and bending. They are not optimized for maximum cutting speed, but they excel in applications that require deformation after machining.

H65 Brass Characteristics
H65 brass (equivalent to C26000 Cartridge Brass) contains about 65% copper and offers excellent ductility, good corrosion resistance, and a bright, polished surface finish. It is widely used for electronic components, decorative hardware, and parts that require brass deep drawing.

Because of its high ductility, H65 produces long, ribbon-like chips during machining. This can cause chip evacuation issues in high-volume brass CNC turning operations, especially on Swiss-type machines.

Machining Limitations and Best Practices
When machining H65, lower cutting speeds and specially ground chip breaker inserts are recommended to prevent built-up edge and stringy chip tangling. For complex small parts, Swiss CNC machining with high-pressure coolant delivery helps maintain tight tolerances and surface quality.

H65 is the preferred choice when a part requires both precision machined features and subsequent cold forming operations.

Regulatory pressure for RoHS compliant brass and lead-free components has driven rapid adoption of eco-brass alloys in consumer electronics, plumbing, and medical devices. These alloys replace lead with silicon or other elements to achieve good machinability without toxic additives.

C69300 Silicon Brass Performance
C69300 Silicon Brass is one of the most popular lead-free options. Silicon particles in the microstructure act as chip breakers, delivering machinability close to that of leaded brasses while meeting strict environmental regulations.

This grade also offers excellent corrosion resistance and high strength, making it suitable for plumbing fixtures, drinking water components, and electronics CNC machined parts that require RoHS compliance.

Compliance and Certification Considerations
For global supply chains, it is critical to verify that lead-free brass suppliers provide full material test reports and RoHS certificates. Misclassified or non-compliant material can result in product recalls and regulatory penalties.
 

One of the biggest challenges in global sourcing is matching brass grades across different regional standards. The matrix below cross-references common US, Chinese, and European grades with key performance attributes and typical applications.

This matrix helps engineering and procurement teams quickly identify equivalent materials when sourcing from manufacturers in different regions, reducing qualification time and minimizing material mismatch risks.

Vague material specifications are the number one cause of unexpected cost overruns and performance issues in brass CNC machining projects. Follow these practical tips to ensure your supplier delivers exactly what you need.

Specify Full Grade Designation
Never write "brass" on a drawing. Always include the full standard grade number (such as C36000 or H62) along with the applicable standard (ASTM, GB, EN). This eliminates ambiguity and ensures consistent material sourcing across production runs.

Align Material with Manufacturing Process
Match the alloy to the primary manufacturing method. For example, choose free-cutting grades for high-volume CNC turned parts, and ductile grades for parts that require post-machining forming. Selecting the wrong grade can double machining time or cause part failure during secondary operations.

Balance Cost and Performance
While C36000 offers the lowest machining cost, it may not meet corrosion or compliance requirements. Conversely, premium lead-free or naval grades add cost that is unnecessary for indoor, non-critical applications.

Work with your machining partner early in the design phase to optimize material selection for both performance and total cost.

Consult our brass material engineering team