S-91257A806 5/8"-11 x 3" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum load-bearing capacity with 150,000 psi tensile strength and Grade 8 classification for critical structural applications
• Superior corrosion resistance through zinc yellow-chromate plating that withstands harsh industrial environments
• Enhanced installation efficiency with external hex drive design providing secure tool engagement and high torque capability
• Reliable thread engagement featuring UNC coarse threads and Class 2A fit for consistent performance in vibration-prone applications
• Optimized material strength with Rockwell C33 hardness ensuring durability under extreme mechanical stress
• Versatile partial threading allowing for both clamping and alignment functions in complex assemblies
• Industry compliance assurance meeting ASME B18.2.1 and SAE J429 specifications for quality and reliability

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver exceptional engineering value in demanding industrial environments where failure is not an option. The 150,000 psi tensile strength combined with Rockwell C33 hardness provides critical protection against shear and tensile failures in heavy machinery, structural steel connections, and high-vibration equipment. The zinc yellow-chromate plating creates a robust barrier against corrosion in outdoor applications or chemically aggressive settings, significantly extending service life. The UNC coarse thread design ensures rapid installation and superior resistance to vibration loosening, while the external hex drive accommodates high torque requirements without stripping. These partially threaded fasteners are particularly valuable in applications requiring precise clamping force distribution, making them ideal for construction equipment, automotive assemblies, and industrial machinery where reliability and durability are paramount.

Specification Summary & Compliance

This 5/8"-11 UNC hex head screw maintains precise Class 2A thread fit tolerances and features a 3" length with 1 1/2" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical performance. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications requiring strict regulatory adherence.