S-91211A203 5/8"-11 x 1 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking 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 industrial environments
• Superior vibration resistance through nylon patch thread locking that maintains integrity across -55° to 250°F temperature ranges
• Enhanced corrosion protection with zinc yellow-chromate plating that extends service life in demanding conditions
• Precise installation and removal thanks to external hex drive design and Class 2A thread fit for consistent engagement
• Maximum thread engagement through fully threaded 5/8"-11 UNC coarse configuration for superior holding power
• Verified material quality with Rockwell C33 hardness ensuring consistent durability and wear resistance
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interoperability

Professional Applications & Engineering Value

Engineered for critical fastening applications where failure is not an option, these Grade 8 hex head screws deliver exceptional performance in heavy machinery, structural assemblies, and industrial equipment. The zinc yellow-chromate plated steel construction provides superior corrosion resistance in harsh environments, while the nylon patch thread locker effectively counters vibration-induced loosening - a common failure point in dynamic applications. The 5/8"-11 UNC coarse thread design ensures rapid installation and maximum clamping force, with fully threaded configuration offering consistent engagement throughout the fastener length. These industrial screws are specifically designed to maintain integrity under extreme mechanical stress, making them ideal for construction equipment, automotive assemblies, and manufacturing infrastructure where high tensile strength and vibration resistance are paramount requirements.

Specification Summary & Compliance

This Grade 8 hex head screw features precise Class 2A thread fit tolerance for consistent mating with standard nuts and threaded holes. Manufacturing complies with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and material properties. The 5/8"-11 UNC coarse thread configuration maintains standard industrial threading specifications, while the external hex drive design provides reliable torque transmission. The fastener meets industry standards for heavy-duty applications with verified 150,000 psi tensile strength and Rockwell C33 hardness certification.