S-91268A819 5/8"-11 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance under extreme loads and prevents fastener failure in demanding applications
• Grade 8 steel construction with Rockwell C33 hardness provides superior durability and resistance to wear, deformation, and shear forces
• Partial threading design offers optimal grip strength while reducing weight and material costs compared to fully threaded alternatives
• Coarse UNC thread pattern with Class 2A fit enables faster installation and superior resistance to vibration loosening in industrial environments
• External hex drive configuration allows for high-torque application with standard tools, ensuring secure fastening in confined spaces
• Comprehensive regulatory compliance including RoHS 3 and REACH ensures environmental safety and global market acceptance
• ASME B18.2.1 standard compliance guarantees dimensional accuracy and interchangeability with existing industrial systems

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment where vibration resistance and load-bearing capacity are paramount. The 5/8"-11 UNC coarse thread configuration provides superior holding power in soft materials and faster installation times, while the partial threading design concentrates strength where needed most. Manufactured from high-grade steel with precise Rockwell C33 hardness, these fasteners maintain integrity under repeated stress cycles and extreme environmental conditions. The external hex drive facilitates high-torque application in confined spaces, making them ideal for construction, automotive, and manufacturing applications requiring dependable, high-strength fastening solutions that meet rigorous industrial standards.

Specification Summary & Compliance

This 4" length hex head screw features precise Class 2A thread fit tolerances and UNC coarse threading per ASME/ANSI standards. The fastener complies with ASME B18.2.1 dimensional specifications and SAE J429 material standards for Grade 8 requirements. Manufacturing and material compliance includes RoHS 3 (2015/863/EU) environmental directives and REACH (EC 1907/2006) regulations regarding substance restrictions, ensuring global regulatory acceptance for industrial applications.