S-91257A848 3/4"-10 x 3 1/4" 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 applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimized thread engagement through UNC coarse threading and Class 2A fit ensures secure fastening and vibration resistance
• High-grade material strength with Grade 8 classification and Rockwell C33 hardness for consistent mechanical properties
• Enhanced torque application through 1 1/8" external hex head design for easier installation and removal
• Versatile partial threading allows for both clamping strength and adjustment flexibility in assembled components
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429 standards and environmental regulations including RoHS 3 and REACH

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions for industrial applications where failure is not an option. The combination of 150,000 psi tensile strength and Rockwell C33 hardness provides exceptional resistance to elongation and shear forces in heavy machinery, structural steel connections, and equipment manufacturing. The zinc yellow-chromate plating offers superior protection against corrosion in demanding environments, while the 3/4"-10 UNC coarse thread design ensures rapid assembly and reliable performance in vibration-prone applications. The partially threaded configuration provides optimal stress distribution, making these heavy-duty hex bolts ideal for critical joints requiring both clamping force and adjustability in construction, automotive, and industrial equipment sectors.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit with 3/4"-10 UNC coarse thread specifications and partial threading extending to minimum 1 3/4" length. Manufactured to ASME B18.2.1 and SAE J429 Grade 8 standards, ensuring dimensional accuracy and mechanical consistency. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, providing assurance for global industrial applications requiring verified material safety and performance reliability.