S-91257A913 7/8"-9 x 3" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength and Grade 8 classification for reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in demanding industrial environments
• Optimized thread engagement through UNC coarse threading and Class 2A fit ensures secure fastening and vibration resistance
• Enhanced durability with Rockwell C33 hardness maintains structural integrity under repeated loading conditions
• Easy installation and removal with external hex drive and 1 5/16" head width for standard tool compatibility
• Versatile partial threading allows for precise clamping force distribution across the 3" length
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for quality and safety

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for heavy machinery, structural assemblies, and industrial equipment where failure is not an option. The steel construction with Rockwell C33 hardness provides exceptional resistance to shear and tensile forces, while the zinc yellow-chromate plating protects against corrosive elements in manufacturing, construction, and marine environments. The 7/8"-9 UNC coarse thread design ensures rapid installation and superior holding power in thick materials, with partial threading allowing unthreaded shank sections to bear against mating surfaces without thread damage. These industrial strength fasteners are engineered to maintain integrity under extreme vibration and dynamic loading conditions common in automotive, aerospace, and heavy equipment applications.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerances and UNC coarse thread specifications. These hex head screws comply with ASME B18.2.1 and SAE J429 manufacturing standards, ensuring consistent quality and performance. The fasteners are fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting current environmental regulations for industrial components. With a defined minimum thread length of 2" on the 3" overall length and right-hand thread direction, these screws provide reliable fastening solutions for professional applications requiring certified components.