Bronze CSK Flat Head Screws
Comprehensive Overview of Bronze Countersunk Flat Head Screws
We are a specialized manufacturer and global supplier of precision Bronze Countersunk Flat Head Screws (CSK), engineered for applications requiring flush mounting, aerodynamic surfaces, and corrosion resistance. Our flat head screws are manufactured from high-performance bronze alloys including C63000 Aluminum Nickel Bronze for maximum strength, C65500 Silicon Bronze for superior marine corrosion resistance, and C93200 Bearing Bronze for excellent machinability and bearing properties. These precision fasteners feature a conical head with a flat top that sits flush with the material surface when installed in a countersunk hole. With our advanced CNC machining and thread rolling capabilities, we deliver CSK screws that meet the most demanding specifications for marine, architectural, and machinery applications.
Bronze CSK Flat Head Screws – Flush Mounting Excellence
Bronze Countersunk Flat Head Screws are designed to provide a smooth, flush surface when installed in countersunk holes. The conical head design allows the screw to sit perfectly flush with the workpiece surface, making these screws ideal for applications where protruding fastener heads are not acceptable. Bronze construction ensures excellent corrosion resistance, non-sparking properties, and long-term reliability in demanding environments.
Applications of Bronze CSK Flat Head Screws
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Marine Craft Construction: Hull plating, decking, and trim where smooth surfaces are essential
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Architectural Metalwork: Decorative panels, handrails, and fixtures requiring seamless appearance
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Aerospace Components: Panels and fairings where aerodynamic surfaces are critical
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Machinery Guards: Safety covers and enclosures requiring smooth surfaces
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Food Processing Equipment: Sanitary applications where crevice-free surfaces are mandatory
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Transportation Industry: Interior paneling and trim in marine and rail applications
Bronze Alloy Specifications for CSK Flat Head Screws
| Bronze Alloy | UNS Designation | Key Properties | Typical Applications |
|---|---|---|---|
| C65500 Silicon Bronze | C65500 | Excellent corrosion resistance, good strength, non-sparking | Marine applications, architectural, coastal structures |
| C63000 Aluminum Nickel Bronze | C63000 | Very high strength, excellent wear resistance | High-stress machinery, structural applications |
| C93200 Bearing Bronze | C93200 | Excellent machinability, good bearing properties | General purpose, low-stress applications |
Bronze CSK Screw Technical Specifications
| Parameter | C65500 (Silicon Bronze) | C63000 (Aluminum Nickel Bronze) | C93200 (Bearing Bronze) |
|---|---|---|---|
| Tensile Strength (MPa) | 448 – 552 | 655 – 895 | 240 – 380 |
| Yield Strength (MPa) | 207 (Min) | 275 – 620 | 125 – 210 |
| Head Angle | 82° ± 1° / 90° ± 1° | 82° ± 1° / 90° ± 1° | 82° ± 1° / 90° ± 1° |
| Drive Types | Phillips, Slotted, Socket | Phillips, Slotted, Socket | Phillips, Slotted, Socket |
| Corrosion Resistance | Excellent | Excellent | Good |
Standard Sizes: M3 to M12, #4 to 1/2″ diameter. Lengths from 6mm to 100mm.
Threads: Metric Coarse, Metric Fine, UNC, UNF
Standards: ISO 10642, DIN 963, DIN 964, ASME B18.6.2
Head Angles: Standard 82° and 90° included angles available
Design Features & Benefits
CSK Head Design Advantages
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Flush Mounting: Head sits completely flush with material surface for smooth finish
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Aerodynamic Surfaces: Essential for applications where air or fluid flow is critical
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Safety Enhancement: Eliminates protruding head hazards in public spaces
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Aesthetic Appeal: Clean, seamless appearance for architectural applications
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Space Optimization: Maximum use of available space in compact designs
Performance Characteristics
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Corrosion Resistance: Excellent performance in marine and chemical environments
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Non-Sparking Safety: Safe for explosive atmospheres and hazardous locations
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High Strength: Capable of withstanding significant tensile and shear loads
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Non-Magnetic Properties: Ideal for sensitive electronic and medical equipment
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Excellent Machinability: Precision manufacturing for perfect head geometry
Manufacturing Processes & Quality Control
Our Bronze CSK Flat Head Screws are manufactured through a precision-controlled process:
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Material Selection: Certified bronze alloy bar stock
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CNC Machining: Precision turning of screw blanks and head geometry
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Head Forming: Precision machining of countersunk head with exact angles
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Drive Feature Machining: Cutting of Phillips, slotted, or socket drive
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Thread Rolling: Precision thread formation using flat-die rolling
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Heat Treatment: Stress relieving for dimensional stability
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Deburring & Finishing: Comprehensive edge breaking and surface polishing
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Quality Inspection: 100% dimensional verification and sample testing
Quality Assurance Tests:
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Head Angle Verification: Precision gauging of head angle to ±1° tolerance
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Head Diameter Check: Verification of head dimensions and concentricity
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Drive Feature Inspection: Depth and geometry of drive recess
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Thread Gauging: Go/No-Go thread acceptance testing
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Flushness Testing: Verification of head-to-shank transition
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Material Certification: Mill Test Certificates for full traceability
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Salt Spray Testing: Corrosion resistance validation per ASTM B117
Technical Data & Performance Specifications
Head Dimensions & Specifications
| Screw Size | Head Diameter | Head Height | Head Angle | Countersink Diameter |
|---|---|---|---|---|
| M4 | 7.5 mm | 2.4 mm | 82° / 90° | 8.0 mm / 7.6 mm |
| M5 | 9.2 mm | 2.7 mm | 82° / 90° | 9.8 mm / 9.3 mm |
| M6 | 11.0 mm | 3.3 mm | 82° / 90° | 11.8 mm / 11.2 mm |
| M8 | 14.5 mm | 4.0 mm | 82° / 90° | 15.4 mm / 14.6 mm |
| M10 | 17.5 mm | 5.0 mm | 82° / 90° | 18.6 mm / 17.7 mm |
Drive Type Specifications
| Drive Type | Advantages | Torque Capacity | Applications |
|---|---|---|---|
| Phillips | Self-centering, common driver | Medium | General purpose, production |
| Slotted | Universal compatibility | Low | Decorative, low torque |
| Socket | High torque, precise installation | High | Machinery, high-stress applications |
Installation Guidelines & Technical Data
Countersink Hole Specifications
| Screw Size | Drill Size (Through) | Countersink Diameter | Countersink Depth |
|---|---|---|---|
| M4 | 4.2 mm | 8.0 mm (82°) / 7.6 mm (90°) | 2.6 mm |
| M5 | 5.2 mm | 9.8 mm (82°) / 9.3 mm (90°) | 2.9 mm |
| M6 | 6.2 mm | 11.8 mm (82°) / 11.2 mm (90°) | 3.5 mm |
| M8 | 8.2 mm | 15.4 mm (82°) / 14.6 mm (90°) | 4.2 mm |
| M10 | 10.2 mm | 18.6 mm (82°) / 17.7 mm (90°) | 5.2 mm |
Torque Specifications
| Screw Size | C65500 (Nm) | C63000 (Nm) | C93200 (Nm) |
|---|---|---|---|
| M4 | 1.8 – 2.2 | 2.5 – 3.0 | 1.2 – 1.5 |
| M5 | 3.5 – 4.2 | 4.8 – 5.8 | 2.4 – 2.9 |
| M6 | 6.0 – 7.2 | 8.3 – 10.0 | 4.2 – 5.0 |
| M8 | 14.0 – 17.0 | 19.5 – 23.5 | 9.8 – 11.8 |
| M10 | 28.0 – 34.0 | 39.0 – 47.0 | 19.5 – 23.5 |
Frequently Asked Questions (FAQ)
Q1: What is the difference between 82° and 90° head angles?
The 82° head angle is the international standard (ISO), while the 90° head angle is more common in North America (ANSI). The choice depends on your countersink tooling and application requirements. We manufacture both standards to ensure proper seating and flush mounting.
Q2: Can bronze CSK screws be used in aluminum structures?
Yes, bronze CSK screws are excellent for use with aluminum as they have similar corrosion characteristics and create a compatible galvanic couple. This prevents the severe galvanic corrosion that occurs when steel fasteners are used with aluminum.
Q3: What drive type is recommended for high-torque applications?
For high-torque applications, socket head drives are recommended as they provide the highest torque capacity and minimize the risk of cam-out. Phillips drives are suitable for general applications, while slotted drives are primarily for decorative or low-torque applications.
Q4: Do you offer different finish options for architectural applications?
Yes, we can provide various finishes including:
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Natural bronze finish (as-machined)
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Polished finish for decorative applications
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Satin finish for architectural hardware
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Patina finishes for historical restoration
Q5: What is the maximum thickness for countersunk applications?
The maximum practical thickness is determined by screw length and head design. We typically recommend that the material thickness should be at least 1.5 times the screw diameter to ensure proper thread engagement and clamping force.
Why Choose Our Bronze CSK Flat Head Screws?
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Precision Head Geometry: Exact head angles and dimensions for perfect flush mounting
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Material Expertise: Optimal alloy selection for specific application requirements
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Quality Assurance: Comprehensive inspection of head geometry and thread quality
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Technical Support: Engineering assistance for installation and application
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Custom Capabilities: Special lengths, diameters, and drive configurations
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Complete Traceability: Material certifications and manufacturing documentation
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Global Standards Compliance: Manufacturing to international quality standards
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Competitive Pricing: Cost-effective manufacturing without quality compromise
Call to Action – Contact Us Today
Achieve perfect flush mounting with our precision bronze CSK flat head screws. Contact us for quotations or technical assistance.
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Request a Quote: Email your specifications to sales@jambrass.com for prompt quotation
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Call Directly: +91-22-43449300 / +91-22-43449323 (Monday-Saturday, 9:00 AM – 6:00 PM IST)
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Office Address: 1406, 14th Floor, Dalamal Tower, Nariman Point, Mumbai – 400021, Maharashtra, India
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Factory Address: Plot 10B, GIDC Industrial Estate, Shanker Tekari, Udyognagar, Jamnagar, Gujarat – 361004
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Samples Available: Contact us for evaluation samples
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Technical Consultation: Our engineers are available for application support
We look forward to providing you with the highest quality bronze CSK flat head screws for your most demanding applications.
