S-91253A562 1/4"-20 x 3 1/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• Superior mechanical strength with 130,000 psi tensile strength and Rockwell C39 hardness for heavy-duty applications
• Precise thread engagement with Class 3A fit and UNC coarse threads ensuring reliable fastening performance
• Optimized installation efficiency through hex drive design and partial threading for faster assembly
• Flush mounting capability with 82° countersink angle and standard flat head profile for seamless surface integration
• Regulatory compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for global industrial use
• Enhanced durability through alloy steel construction maintaining performance under extreme conditions

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these black-oxide alloy steel flat head screws deliver exceptional performance in machinery assembly, automotive components, and structural frameworks. The UNC coarse threading combined with Class 3A thread fit provides superior resistance to vibration loosening, while the partial threading design allows for precise clamping force distribution. The hex drive configuration ensures maximum torque transmission during installation, reducing stripping risks and improving worker safety. The 82° countersink angle facilitates perfect flush mounting in various materials, eliminating protrusions that could interfere with mechanical operations. These screws are particularly valuable in applications requiring repeated disassembly and reassembly, where their Rockwell C39 hardness maintains thread integrity over multiple cycles.

Specification Summary & Compliance

This 1/4"-20 UNC flat head screw features precise Class 3A thread fit with coarse thread spacing and partial threading up to 1" minimum thread length. Manufacturing complies with ASTM F835 specifications for mechanical properties and dimensional accuracy. The product is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations concerning chemical substances, ensuring environmental responsibility and workplace safety standards.