S-91257A777 9/16"-12 x 6" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength for demanding structural and machinery applications
• Superior corrosion protection through zinc yellow-chromate plating, extending service life in harsh industrial environments
• Optimized torque transmission with external hex drive and 13/16" head width for secure installation using standard tools
• Reliable thread engagement with UNC coarse threads and Class 2A fit ensuring consistent clamping force and vibration resistance
• Grade 8 material certification providing verified hardness (Rockwell C33) for high-stress applications
• Partial threading design offering both gripping strength and clearance flexibility in assembly operations
• Regulatory compliance assurance meeting ASME B18.2.1 mechanical specifications and environmental standards (RoHS 3/REACH)

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical performance where failure isn't an option. The steel construction hardened to Rockwell C33 provides structural integrity for heavy machinery, construction equipment, and industrial framing. The 9/16"-12 UNC coarse thread configuration ensures rapid assembly while maintaining holding power in steel-to-steel connections. Zinc yellow-chromate plating creates a sacrificial barrier against oxidation and chemical exposure, significantly outperforming standard zinc coatings in humid or corrosive environments. The 6" length with partial threading allows for both deep penetration in thick materials and unthreaded shank strength where shear forces are present. Engineered to ASME B18.2.1 standards, these fasteners provide predictable performance in critical joints subject to dynamic loads and vibration.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit with 9/16"-12 UNC coarse threads and minimum thread length of 1-3/8". Manufactured to Grade 8 strength classification with 150,000 psi tensile strength. Compliant with ASME B18.2.1 dimensional standards and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for hazardous substance restrictions.