COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF UNS C36000 FREE-CUTTING BRASS FASTENERS
UNS C36000, globally recognized as "Free-Cutting Brass" or "Alloy 360," is the undisputed benchmark for metal machinability. Across the entire metallurgical industry, C36000 is set as the standard by which all other metals are judged, boasting a perfect 100% Machinability Rating. This remarkable characteristic is achieved by alloying a standard copper-zinc brass base with a precisely controlled addition of Lead (2.5% to 3.7%).
Because Lead is practically insoluble in solid copper and zinc, it disperses throughout the microstructure as microscopic globules. During high-speed CNC turning, threading, or milling, these lead particles act as a built-in dry lubricant and cause the metal chips to break off cleanly and sharply. This prevents the "gummy" tool-wrap associated with pure copper or high-ductility brass, making C36000 the ultimate choice for highly complex, custom-machined threaded fasteners, knurled thumb screws, and precision spacers.
■ Product Overview & Specifications
| Material Classification | Leaded Alpha-Beta Brass (Free-Machining Brass) |
|---|---|
| UNS Designation | C36000 |
| Microstructure | Alpha-Beta Phase with Dispersed Lead Particles |
| Magnetic State | Completely Non-Magnetic |
| Density | 8.50 g/cm³ (0.307 lb/in³) |
| Size Range | Metric: M1.6 to M36 | Imperial: #0 to 1-1/2" |
| Primary Attribute | The Industry Standard 100% Machinability Benchmark |
■ Proprietary Datasheet Download (GATED)
UNS C36000 Free-Cutting Brass — Complete Technical Datasheet
Contains detailed CNC thread-cutting tolerances, recommended high-speed feed rates for automated screw machines, and knurling pitch specifications for custom tactile hardware.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
In high-speed manufacturing, inconsistent lead dispersion can cause tool chatter and poor thread finishes. Ananka ensures that all C36000 solid bar stock used for CNC fastener production is backed by rigorous mill certification to guarantee uniformity.
- EN 10204 Type 3.1: Validates the exact 2.5% - 3.7% Lead inclusion, caps Iron impurities (which dull cutting tools), and confirms the half-hard temper required for clean threading.
- EN 10204 Type 3.2: Available upon request for specialized pneumatic, fluid-power, or aerospace instrument contracts requiring third-party testing oversight.
■ Chemical Composition
The defining characteristic of C36000 is its controlled Lead (Pb) content. Unlike Cartridge Brass (which minimizes lead to maximize ductility), Free-Cutting Brass relies heavily on lead to purposely create microscopic shear points in the metal matrix, optimizing it for cutting tools rather than forming dies.
| Copper (Cu) | Lead (Pb) | Iron (Fe) | Zinc (Zn) |
|---|---|---|---|
| 60.0 – 63.0 | 2.50 – 3.70 | 0.35 Max | Balance (~35.5) |
■ Mechanical Properties
| Mechanical Property | Typical Limits (Half-Hard Temper / Machined) |
|---|---|
| Tensile Strength | 45,000 - 68,000 psi (310 - 470 MPa) |
| Yield Strength | 15,000 - 45,000 psi (105 - 310 MPa) |
| Machinability Rating | 100% (The Benchmark Standard) |
| Hardness (Rockwell B) | 70 - 80 HRB |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| ASTM Specifications | ASTM B16 (Free-Cutting Brass Rod, Bar) |
| Common Trade Names | Alloy 360, Free-Machining Brass, 360 Brass |
| European Equivalent | EN CW603N / CuZn36Pb3 (DIN 2.0375) |
| British Standard (BS) | CZ124 |
■ Applications & Industries
- Precision Instruments & Electronics: Custom machined standoffs, hex spacers, and internal binding screws for motherboards and electronic enclosures.
- Pneumatic & Fluid Power: Valve bodies, threaded pipe fittings, and hose connectors where complex internal and external threading is required.
- Aesthetic & Tactile Hardware: Custom knurled thumb screws, decorative panel fasteners, and architectural hardware benefiting from the bright yellow-brass finish.
■ Compatible Fastener Assemblies
| Mating Fasteners | Internal Threads | Washers |
|---|---|---|
| C36000 CNC Turned Machine Screws / Studs | C36000 Custom Hex & Knurled Nuts | C26000 Flat Washers (Stamped) |
■ Torque & Installation Guidelines
C36000 fasteners are typically smaller, precision-machined parts. While the metal cuts beautifully, it has a relatively low yield strength compared to alloy steels. Overtorquing will easily shear off the fastener head or strip fine threads. Clean, dry installation is typically recommended to prevent over-lubrication yielding.
| Nominal Diameter | Threads Per Inch (UNC) | Max Target Torque (in-lbs) | Max Target Torque (ft-lbs) |
|---|---|---|---|
| #6 | 32 | 12 - 15 | ~ 1 |
| #10 | 24 | 30 - 35 | ~ 2.5 |
| 1/4" | 20 | 60 - 70 | ~ 5.5 |
| 3/8" | 16 | 180 - 200 | ~ 16 |
■ Frequently Asked Questions
1. Can C36000 Free-Cutting Brass be cold-headed or forged?
No. The exact property that makes C36000 perfect for machining—the microscopic lead particles—makes it terrible for cold-heading. If you attempt to cold-head or severely bend Alloy 360, the lead inclusions will act as fracture points, causing the metal to crack and shatter. Fasteners made from C36000 are exclusively manufactured via CNC turning and cutting from solid bar stock. If cold-heading is required, C26000 Cartridge Brass must be used.
2. Is C36000 suitable for drinking water plumbing applications?
Generally, no. Due to strict modern regulations like the Safe Drinking Water Act (SDWA) and European RoHS directives, the 2.5% to 3.7% lead content in C36000 makes it non-compliant for components that directly contact potable drinking water. For drinking water applications, specialized "Lead-Free" free-machining brasses (such as C46400 Naval Brass or C69300 EcoBrass) are specified instead.
3. Will C36000 fasteners tarnish over time?
Yes. Like most brasses, C36000 is resistant to destructive rust, but it will naturally oxidize and form a dull brown or greenish patina over time when exposed to the atmosphere. If the bright, golden aesthetic is required permanently, the fasteners must be clear-coated, lacquered, or routinely polished.