S-91257A766 9/16"-12 x 2 1/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for demanding industrial applications
• Enhanced corrosion protection through Zinc Yellow-Chromate plating, extending service life in harsh environments
• Optimized installation efficiency with external hex drive design providing secure tool engagement and torque transmission
• Reliable thread engagement with Class 2A fit UNC coarse threads ensuring consistent fastening performance
• Reduced weight and material usage through partially threaded design while maintaining full strength at critical stress points
• Exceptional hardness and durability with Rockwell C33 rating resisting wear and deformation under heavy loads
• Broad compatibility with standard inch-system components and industrial equipment requiring 9/16"-12 UNC threading

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical performance in heavy machinery, structural steel connections, and industrial equipment where high tensile strength and reliable fastening are paramount. The steel construction with Rockwell C33 hardness provides exceptional resistance to shear forces and vibrational loosening, while the Zinc Yellow-Chromate plating creates a protective barrier against oxidation and chemical exposure in manufacturing environments. The 9/16"-12 UNC coarse thread configuration ensures rapid installation and superior holding power in steel-to-steel applications, with the partially threaded design concentrating strength where needed most. Engineered to withstand extreme mechanical stress, these industrial fasteners prevent joint failure in critical assemblies, reducing maintenance downtime and enhancing operational safety across construction, automotive, and heavy equipment sectors.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance for consistent mating with standard nuts and tapped holes. Complies with ASME B18.2.1 and SAE J429 specifications for hex head screws, ensuring interchangeability and performance reliability. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards, containing no restricted substances. Features 9/16"-12 UNC coarse threads in right-hand direction with minimum thread length of 1-3/8" on a 2-1/4" overall length fastener.