S-91247A890 7/8"-9 x 4 1/2" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 120,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through zinc plating, extending service life in harsh industrial environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit for faster assembly and secure fastening
• Enhanced torque transmission via external hex drive design, allowing for high tightening forces without slippage
• Grade 5 strength certification ensuring consistent mechanical properties and Rockwell C25 hardness for durability
• Partial threading design providing both gripping strength and clearance where needed in structural applications
• Full regulatory compliance with ASME B18.2.1, SAE J429 standards plus RoHS 3 and REACH environmental directives

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers critical engineering solutions for heavy-duty industrial applications where structural integrity is paramount. The 7/8"-9 UNC coarse thread configuration ensures rapid installation and superior resistance to vibration loosening in machinery, construction, and equipment manufacturing. The zinc plated finish provides essential corrosion protection for outdoor applications or environments with moisture exposure. With partial threading and substantial 4 1/2" length, this fastener offers optimal clamp load distribution while allowing unthreaded shank sections to function as precision alignment features. The external hex drive accommodates high torque requirements, making it ideal for bolted connections requiring significant preload in structural steel, heavy equipment, and industrial machinery assemblies.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with Class 2A thread fit tolerance for consistent performance. Complies with ASME B18.2.1 and SAE J429 specifications for Grade 5 fasteners, ensuring dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards. Features right-hand UNC coarse threads with 0.875" diameter and minimum 2" thread length for secure fastening in various material thicknesses.