S-91257A711 7/16"-20 x 5 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 for reliable performance in high-stress applications
• Superior corrosion resistance through zinc yellow-chromate plating that withstands harsh industrial environments
• Optimized thread engagement with UNF fine thread design providing better vibration resistance and precise fastening
• Enhanced durability with Rockwell C33 hardness ensuring long-term performance under heavy loads
• Secure installation through external hex drive design allowing for high torque application without stripping
• Precision threading with Class 2A thread fit ensuring consistent performance and easy assembly
• Regulatory compliance meeting ASME B18.2.1 and SAE J429 standards for quality assurance

Professional Applications & Engineering Value

This Grade 8 hex head screw delivers exceptional engineering value for heavy-duty industrial applications where failure is not an option. The 7/16"-20 UNF fine thread configuration provides superior vibration resistance compared to coarse threads, making it ideal for machinery, equipment manufacturing, and structural assemblies subject to dynamic loads. The zinc yellow-chromate plating creates a robust barrier against corrosion in demanding environments, while the partially threaded design ensures optimal stress distribution along the shank. With 150,000 psi tensile strength and Rockwell C33 hardness, this fastener maintains integrity under extreme pressure, preventing costly downtime and maintenance in critical applications from construction to heavy equipment manufacturing.

Specification Summary & Compliance

This industrial-grade hex head screw features precise Class 2A thread fit tolerances with 7/16"-20 UNF fine threading and partial threading up to 1 1/8" minimum thread length. Manufactured to exacting ASME B18.2.1 and SAE J429 Grade 8 specifications, the fastener ensures dimensional accuracy and performance reliability. The product maintains full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications requiring strict regulatory adherence.