Why Brass?
Brass has been a preferred material for fasteners for centuries, valued for its unique combination of properties that distinguish it from steel and stainless steel alternatives. Unlike ferrous materials, brass does not rust; instead, it develops a natural patina over time that many designers find aesthetically appealing. More importantly, brass offers several functional advantages:
| Property | Benefit |
|---|---|
| Corrosion Resistance | Naturally resistant to moisture, salt air, and many chemicals; ideal for marine, coastal, and outdoor applications |
| Non-Magnetic | Completely non-ferromagnetic; essential for electronic equipment, MRI rooms, compass housings, and sensitive instrumentation |
| Electrical Conductivity | Good electrical conductivity; suitable for grounding applications and electrical terminals |
| Antimicrobial | Copper-based alloy exhibits natural antimicrobial properties; preferred for food handling equipment, medical devices, and sanitary installations |
| Aesthetic Appeal | Warm golden appearance; complements brass hardware, lighting fixtures, and decorative trim |
Material Specification: C36000 / CZ121 Brass
Our brass hex socket cap screws are manufactured from C36000 free-cutting brass (European equivalent CZ121), a high-machinability alloy specifically formulated for precision turned components. This material grade offers:
Machinability Rating: 100% (the benchmark for machinability, enabling precise thread forms and socket geometry)
Tensile Strength: 340–470 MPa, sufficient for most decorative and light-to-moderate structural applications
Yield Strength: 170–310 MPa
Hardness: 80–100 HRB
Composition: Approximately 61.5% copper, 35.5% zinc, 3% lead (for machinability)
The material is leaded to achieve exceptional machining precision; for applications requiring lead-free brass, alternative formulations (such as C69300 or Eco-Brass) are available upon request.
Head Design: Cylindrical Cup Head Profile
The cup head—also known as a socket cap head or cylindrical head—is characterized by its straight cylindrical sides and flat top surface with a central hexagon socket drive. This profile offers several advantages:
Uniform Appearance: The consistent cylindrical shape provides a clean, professional look when installed
Full Bearing Surface: The flat underside distributes clamping force evenly across the mating surface
Low Profile Height: The head height is proportionally balanced to provide adequate socket depth while maintaining a compact overall profile
Precision Socket: The hexagon socket is precisely formed to ensure full engagement with standard Allen keys, minimizing the risk of rounding or stripping
Hex Socket Drive: Superior Torque Transmission
The hex socket (Allen) drive is widely regarded as the preferred drive system for precision fastening applications. Compared to cross-recess drives like Phillips or Pozidriv, the hex socket offers:
| Drive Characteristic | Hex Socket Benefit |
|---|---|
| Cam-Out Resistance | Virtually eliminates cam-out; the bit engages fully within the socket, preventing the driver from slipping out under torque |
| Torque Capacity | Higher torque transmission capability for the same head size; allows proper seating without drive damage |
| Tool Availability | Standard Allen keys and power tool bits are universally available |
| Aesthetics | Clean, unobtrusive drive recess; does not dominate the fastener appearance |
| Field Serviceability | Simple tooling; easily serviced with basic hand tools |
Thread Forms & Sizing
Our brass hex socket cap screws are available in both metric and inch thread configurations to accommodate international specifications:
| Thread System | Standard | Typical Sizes |
|---|---|---|
| Metric | ISO 4762 / DIN 912 | M2, M2.5, M3, M4, M5, M6, M8, M10, M12 |
| Inch (UNC/UNF) | ASME B18.3 | #0, #2, #4, #6, #8, #10, 1/4″, 5/16″, 3/8″ |
All threads are precision-rolled or cut to Class 6g (metric) or Class 2A (inch) tolerances, ensuring consistent engagement with standard mating components.
Length Range
Brass socket cap screws are available in a comprehensive range of lengths to suit diverse applications:
Short lengths (4–12 mm): Small assemblies, electronic enclosures, thin panel fastening
Medium lengths (12–25 mm): Standard hardware mounting, light machinery assembly, decorative trim
Extended lengths (25–50 mm): Through-fastening, thicker material stacks, structural connections
Custom lengths (50–100 mm): Available upon request for specialized applications
| Parameter | Brass (C36000 / CZ121) |
|---|---|
| Tensile Strength (MPa) | 340 – 470 |
| Yield Strength (MPa) | 170 – 310 |
| Elongation (%) | 15 – 25 |
| Hardness (HRB) | 80 – 100 |
| Density (g/cm³) | 8.44 |
| Electrical Conductivity (% IACS) | 26 – 28 |
| Thermal Conductivity (W/m·K) | 115 – 120 |
| Melting Point (°C) | 885 – 900 |
| Operating Temperature | -40°C to +150°C |
| Magnetic Permeability | 1.0 (non-magnetic) |
| Corrosion Resistance | Good to excellent; resistant to atmospheric corrosion, fresh water, mild chemicals |
| RoHS Compliance | Standard grade contains lead; lead-free alternatives available |
| Thread Size | Head Diameter (max) | Head Height (max) | Socket Size (across flats) |
|---|---|---|---|
| M2 | 3.8 mm | 2.0 mm | 1.5 mm |
| M2.5 | 4.5 mm | 2.5 mm | 2.0 mm |
| M3 | 5.5 mm | 3.0 mm | 2.5 mm |
| M4 | 7.0 mm | 4.0 mm | 3.0 mm |
| M5 | 8.5 mm | 5.0 mm | 4.0 mm |
| M6 | 10.0 mm | 6.0 mm | 5.0 mm |
| M8 | 13.0 mm | 8.0 mm | 6.0 mm |
| M10 | 16.0 mm | 10.0 mm | 8.0 mm |
| M12 | 18.0 mm | 12.0 mm | 10.0 mm |
*Head dimensions conform to ISO 4762 / DIN 912 standards. Custom head dimensions available upon request.*
Architectural Hardware & Decorative Trim
Brass socket cap screws are extensively used in visible applications where the warm golden color of brass complements the surrounding materials. Common installations include door hardware, cabinet pulls, lighting fixtures, railing systems, and decorative architectural elements. The hex socket drive ensures clean installation without the drive damage that often mars visible fasteners.
Marine Equipment & Coastal Applications
The natural corrosion resistance of brass makes it suitable for marine environments where saltwater exposure is a concern. Applications include boat hardware, deck fittings, navigation equipment housings, and interior marine trim. For prolonged saltwater immersion, alternative bronze alloys may be recommended; however, brass performs admirably for above-waterline and interior marine applications.
Electrical & Electronic Assemblies
The non-magnetic and electrically conductive properties of brass make it ideal for electrical applications. These screws are commonly used in terminal blocks, grounding assemblies, control panels, and electronic enclosure assembly. The non-magnetic characteristic is particularly critical in MRI equipment, compass housings, and sensitive instrumentation where ferromagnetic materials are prohibited.
Industrial Equipment & Machinery
For light to medium-duty industrial applications where corrosion resistance and aesthetics are valued, brass socket cap screws provide reliable fastening. They are frequently specified in food processing equipment (leveraging antimicrobial properties), packaging machinery, and specialized manufacturing equipment.
Jewelry & Personal Accessories
The fine appearance of brass socket cap screws makes them suitable for high-end jewelry, watches, eyewear frames, and personal accessories where small, precise fasteners are required. The hex socket drive allows for secure fastening without visible drive damage.
Each production batch undergoes standard quality verification to ensure consistent performance:
Thread Conformance: Go/no-go thread gauging ensures proper fit with standard nuts and tapped holes
Dimensional Accuracy: Head diameter, head height, and overall length verified against ISO/ASME specifications
Socket Integrity: Hex socket dimensions verified; socket strength tested to ensure full torque capacity
Surface Condition: Inspected for burrs, tool marks, and surface defects; edges are broken for safe handling
Material Verification: Chemical composition confirmed per batch; mechanical properties documented
Lot Traceability: Full traceability maintained from raw material to finished product
Packaging Options
Bulk cartons suitable for production line feeding
Anti-corrosion poly bags with desiccant for extended storage
Custom kitting per assembly requirements
Individual packaging for retail or service kit applications
While standard configurations are readily available, we support custom requirements for specialized applications:
| Custom Parameter | Options |
|---|---|
| Material | Standard C36000 (leaded); lead-free brass (C69300 / Eco-Brass); naval brass; silicon bronze |
| Thread Size | Metric M2–M20; inch #0–3/4″; custom pitches |
| Length | 4 mm – 100 mm; any increment |
| Head Style | Standard cup head; low-profile socket head; button head; custom head geometry |
| Drive Type | Hex socket (standard); Torx; tamper-resistant pin-in-hex |
| Surface Finish | Natural (bright), antique, black oxide, nickel plated, chrome plated, lacquered for tarnish resistance |
| Thread Locking | Pre-applied nylon patch for vibration resistance |
| Marking | Laser engraving: size, grade, custom logos |
| Parameter | Detail |
|---|---|
| Minimum Order Quantity | Flexible; sample quantities available; production volumes from 5,000 pieces |
| Stock Availability | Common sizes (M3–M8, 6–30 mm) typically available from stock |
| Lead Time (Custom) | 3–5 weeks depending on complexity and quantity |
| Documentation | Material Test Reports, dimensional inspection, lot traceability, RoHS compliance (lead-free upon request) |
