S-91247A803 5/8"-11 x 2 1/4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with Grade 5 classification and 120,000 PSI tensile strength for reliable performance in heavy-duty applications
• Superior corrosion resistance through zinc plating, extending service life in challenging industrial environments
• Optimized thread engagement with 5/8"-11 UNC coarse threading and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced installation efficiency featuring external hex drive and standard 15/16" head width for easy tool access and torque application
• Controlled thread distribution through partial threading design providing optimal grip strength while reducing material usage
• Consistent mechanical properties with Rockwell C25 hardness maintaining dimensional stability under stress
• Versatile length selection at 2-1/4" with 1-1/2" minimum thread length accommodating various material thicknesses

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers critical engineering solutions for industrial assembly challenges where vibration resistance and structural integrity are paramount. The zinc plated steel construction provides essential corrosion protection for outdoor equipment, machinery frames, and structural steel connections. The 5/8"-11 UNC coarse thread design ensures rapid installation in thick materials while maintaining superior pull-out strength. With partial threading optimizing the stress distribution, this fastener prevents joint loosening in dynamic load applications common in construction, heavy equipment manufacturing, and transportation infrastructure. The external hex drive configuration allows for high-torque installation using standard tools, making it ideal for maintenance operations and production line assemblies where speed and reliability are crucial.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with Class 2A thread fit tolerance ensuring consistent mating with standard nuts. Complies with ASME B18.2.1 and SAE J429 Grade 5 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards, confirming restricted substance-free manufacturing. The right-hand thread direction and coarse thread spacing adhere to North American industrial standards for interchangeability and reliable performance across applications.