S-91253A978 7/8"-9 x 1 3/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Superior load-bearing capacity with 130,000 psi tensile strength for heavy-duty applications
• Precision Class 3A thread fit ensures secure, vibration-resistant connections in critical assemblies
• Optimized countersink seating with 82° head angle for flush mounting and reduced stress concentration
• High-torque installation capability through 9/16" hex drive for efficient assembly with standard tools
• Full threading along 1-3/4" length provides maximum grip and adjustment flexibility
• Regulatory compliance assurance meeting ASTM F835, RoHS 3, and REACH standards for global supply chain integration

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these black-oxide alloy steel flat head screws deliver reliable performance in high-stress environments. The UNC coarse threading combined with Class 3A precision fit ensures rapid installation and superior resistance to vibrational loosening in machinery, structural steel connections, and equipment manufacturing. The 82° countersink angle creates seamless flush mounting surfaces while the Rockwell C37 hardness maintains thread integrity under repeated loading cycles. Ideal for construction equipment, industrial machinery, and transportation applications where high tensile strength and corrosion protection are critical for long-term operational safety.

Specification Summary & Compliance

Manufactured to ASTM F835 specifications with Class 3A thread fit and UNC 7/8"-9 coarse threading. Features include right-hand thread direction, fully threaded 1-3/4" length, and standard flat head profile. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for international industrial markets and regulated applications.