S-91247A511 7/8"-14 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 capacity with 120,000 psi tensile strength and Rockwell C25 hardness for reliable performance in demanding applications
• Superior corrosion resistance through zinc plating, extending service life in harsh industrial environments
• Precise thread engagement with Class 2A thread fit and UNF fine thread profile for secure fastening and vibration resistance
• Optimized torque transmission via external hex drive and substantial 1 5/16" head width for easy installation with standard tools
• Versatile partial threading design allowing for both clamping and alignment functions in structural assemblies
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for guaranteed interchangeability
• Environmental responsibility with RoHS 3 and REACH compliance, ensuring safe use across regulated industries

Professional Applications & Engineering Value

This 7/8"-14 UNF Grade 5 hex head screw delivers critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment assembly. The zinc plated steel construction provides essential corrosion protection in manufacturing facilities and outdoor applications, while the UNF fine thread configuration maintains superior clamping force under vibration and dynamic loads. The partially threaded design allows the unthreaded shank to function as a precision alignment pin in structural steelwork and machinery frames. With external hex drive and substantial head dimensions, installation torque is efficiently transferred without stripping, making it ideal for high-stress applications requiring repeated maintenance access. This fastener's combination of Grade 5 strength classification and precise Class 2A thread fit ensures reliable performance in critical joints where failure is not an option.

Specification Summary & Compliance

Manufactured to exacting inch system dimensions with 4 1/2" length and 2" minimum thread length. Thread specifications include 7/8"-14 UNF fine thread with Class 2A thread fit tolerance for precise engagement. Complies with ASME B18.2.1 and SAE J429 standards for dimensional consistency and mechanical properties. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for use in regulated industries.