S-91257A468 3/8"-24 x 5 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum load-bearing capability with 150,000 psi tensile strength and Grade 8 classification for critical structural applications
• Superior corrosion protection through zinc yellow-chromate plating that withstands harsh industrial environments
• Precise thread engagement with Class 2A thread fit and UNF fine threading for vibration-resistant connections
• High durability backed by Rockwell C33 hardness that maintains integrity under repeated stress
• Optimized partial threading design providing both gripping power and clearance where needed
• Easy installation and removal with external hex drive and standard 9/16" head width
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for reliable performance

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver exceptional engineering value in demanding applications where failure is not an option. The 3/8"-24 UNF fine thread configuration provides superior resistance to vibration loosening in machinery, construction equipment, and heavy-duty structural assemblies. The zinc yellow-chromate plating creates a robust barrier against corrosion in outdoor or chemically aggressive environments, significantly extending service life. With partial threading and 5 1/2" length, these fasteners offer optimal clamping force distribution while accommodating thick materials. The 150,000 psi tensile strength and Rockwell C33 hardness ensure these screws maintain integrity under extreme mechanical stress, making them ideal for critical connections in industrial machinery, structural steel frameworks, and heavy equipment manufacturing where reliability is paramount.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit tolerances with 3/8"-24 UNF fine threading and partial threading configuration. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 specifications, it delivers consistent performance across industrial applications. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safe use across global markets while maintaining the highest quality standards for industrial fastening solutions.