S-91257A704 7/16"-20 x 3" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for reliable performance in high-stress industrial applications
• Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh environmental conditions
• Precise thread engagement with Class 2A fit and UNF fine threading for vibration resistance and secure fastening
• Optimized torque transmission thanks to the external hex drive design that prevents tool slippage during installation
• Enhanced durability from Rockwell C33 hardness that maintains structural integrity under repeated stress
• Reduced installation time with partially threaded design that allows for quicker positioning in assembly operations
• Regulatory compliance assurance meeting ASME, SAE, RoHS 3, and REACH standards for global industrial applications

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for heavy machinery, structural steel connections, and industrial equipment where failure is not an option. The 7/16"-20 UNF fine threading provides superior resistance to vibrational loosening in dynamic applications, while the zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments. The partially threaded design allows for precise clamp load distribution, making these steel fasteners ideal for applications requiring both high clamping force and alignment accuracy. With their external hex drive and robust construction, they withstand the high torque requirements of industrial assembly while maintaining their mechanical properties in temperature-variable conditions common in manufacturing and construction sectors.

Specification Summary & Compliance

This 3" length hex head screw features precise Class 2A thread fit with UNF fine thread spacing (7/16"-20) ensuring consistent engagement and reliable performance. Manufactured to ASME B18.2.1 and SAE J429 specifications, these fasteners maintain dimensional accuracy and mechanical properties required for critical applications. The product is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations, ensuring environmental responsibility and workplace safety standards are met for global industrial distribution and use.