S-91257A200 3/4"-10 x 4 1/4" 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 resistance through zinc yellow-chromate plating that withstands harsh industrial environments
• Optimized fastening efficiency with partial threading that reduces installation time while maintaining secure connections
• Exceptional durability backed by Rockwell C33 hardness for long-term performance under heavy stress conditions
• Precise thread engagement with Class 2A fit UNC coarse threads ensuring reliable mating with nuts and tapped holes
• Easy installation and removal using standard wrench tools thanks to the external hex drive design
• Industry compliance assurance meeting ASME B18.2.1 and SAE J429 specifications for quality and reliability

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver exceptional engineering value in demanding industrial environments where failure is not an option. The steel construction with zinc yellow-chromate plating creates a robust barrier against corrosion, significantly extending service life in outdoor construction, heavy machinery, and structural steel applications. The 3/4"-10 UNC coarse thread configuration provides superior resistance to vibration loosening while enabling quicker installation compared to fine-thread alternatives. With partial threading optimizing the grip length-to-shank ratio, these fasteners prevent joint slippage in dynamic load conditions. The external hex drive design accommodates high torque applications, making them ideal for critical connections in industrial equipment, bridge construction, and manufacturing infrastructure where 150,000 psi tensile strength ensures structural integrity under extreme pressure.

Specification Summary & Compliance

This Grade 8 hex head screw features precise Class 2A thread fit with 3/4"-10 UNC coarse thread specifications, ensuring dimensional accuracy and reliable mating compatibility. The fastener maintains strict compliance with ASME B18.2.1 dimensional standards and SAE J429 material specifications, guaranteeing consistent performance across industrial applications. Manufacturing adheres to inch system measurements with 4 1/4" length and 1 3/4" minimum thread length for standardized installation. The zinc yellow-chromate plating provides RoHS and REACH compliant corrosion protection while the Rockwell C33 hardness and 150,000 psi tensile strength meet rigorous industrial requirements for heavy-duty fastening solutions.