S-91257A771 9/16"-12 x 3 1/2" 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 environments
• Superior corrosion protection through Zinc Yellow-Chromate plating, extending service life in harsh industrial conditions
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced installation efficiency featuring external hex drive and standard hex head for easy tool access and high torque application
• Precision manufacturing compliance meeting ASME B18.2.1 specifications for consistent dimensional accuracy and interchangeability
• Material reliability with Rockwell C33 hardness providing excellent wear resistance and durability
• Environmental regulation compliance adhering to RoHS 3 and REACH standards for safe usage across global markets

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for heavy-duty industrial applications where structural integrity is paramount. The steel construction combined with Rockwell C33 hardness ensures exceptional resistance to shear forces and material fatigue, making them ideal for construction equipment, machinery assembly, and structural steel connections. The 9/16"-12 UNC coarse thread design provides superior grip in various materials while the partial threading allows for precise clamp load distribution. Zinc Yellow-Chromate plating offers enhanced corrosion protection in demanding environments, while the external hex drive facilitates efficient installation with standard tools. These fasteners address common industrial challenges including vibration loosening, material degradation, and installation efficiency in critical construction and manufacturing applications.

Specification Summary & Compliance

Manufactured to exact Class 2A thread fit tolerances with UNC coarse thread specifications ensuring precise engagement and interchangeability. Compliant with ASME B18.2.1 manufacturing standards for dimensional consistency and performance reliability. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements. The inch system measurements guarantee accurate sizing with 3 1/2" length and 9/16"-12 thread size specifications maintained to industrial standards.