S-91253A451 7/16"-20 x 1" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in demanding industrial environments
• Exceptional tensile strength of 130,000 psi ensures reliable performance under high-stress applications
• Precision Class 3A thread fit guarantees secure fastening and vibration resistance in critical assemblies
• Full threading design provides maximum grip length and uniform load distribution across the entire fastener
• Optimized 82° countersink angle enables flush mounting for streamlined surfaces and improved aerodynamics
• 1/4" hex drive compatibility allows for high-torque installation with standard industrial tools
• Comprehensive regulatory compliance meets ASTM F835, RoHS 3, and REACH standards for global market acceptance

Professional Applications & Engineering Value

These black-oxide alloy steel flat head screws deliver critical performance advantages in precision engineering applications where surface flushness and high tensile strength are paramount. The UNF fine thread spacing combined with Class 3A thread fit provides superior vibration resistance in dynamic equipment, automotive assemblies, and heavy machinery. The 82° countersink angle ensures perfect flush mounting in precision-machined components, while the Rockwell C39 hardness maintains thread integrity through repeated installation cycles. The corrosion-resistant black-oxide finish extends service life in industrial environments where exposure to moisture and chemicals is common, making these fully threaded screws ideal for critical structural applications requiring both precision alignment and long-term reliability.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread tolerances with UNF (Unified National Fine) thread form and 7/16"-20 thread specification. Complies with ASTM F835 standard for alloy steel screws, RoHS 3 (2015/863/EU) restrictions on hazardous substances, and REACH (EC 1907/2006) compliance for chemical safety. Features right-hand thread direction and standard flat head profile with 1" length and 0.844" head diameter for consistent performance across industrial applications.