S-91211A224 3/4"-10 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional Vibration Resistance - Nylon patch thread locker maintains secure fastening from -55° to 250°F, preventing loosening in demanding environments
• Maximum Load-Bearing Capacity - Grade 8 classification with 150,000 psi tensile strength handles extreme mechanical stresses
• Superior Corrosion Protection - Zinc yellow-chromate plated steel construction resists rust and environmental degradation
• Enhanced Durability - Rockwell C33 hardness ensures long-term performance under heavy use conditions
• Optimized Installation Efficiency - External hex drive with 1 1/8" head width provides excellent torque transmission
• Reliable Thread Engagement - Class 2A thread fit with UNC coarse threading ensures consistent, secure connections
• Industry Compliance Assurance - Meets ASME B18.2.1 and SAE J429 specifications for quality and performance standards

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver critical performance where vibration resistance and structural integrity are paramount. The nylon patch thread locking technology effectively counters vibrational loosening in machinery, construction equipment, and automotive assemblies, maintaining clamp force across temperature extremes from -55° to 250°F. The zinc yellow-chromate plated steel construction provides superior corrosion protection in harsh environments, while the UNC coarse threading with Class 2A fit ensures reliable installation and consistent torque values. The partial threading design concentrates strength where needed most, making these high-strength fasteners ideal for critical connections in structural frameworks, heavy machinery, and industrial equipment requiring ASME B18.2.1 compliance.

Specification Summary & Compliance

These 3/4"-10 hex head screws feature Class 2A thread fit tolerance with UNC coarse threading and partial threading configuration. Manufacturing complies with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and performance reliability. The fasteners meet industry standards for Grade 8 strength classification with verified 150,000 psi tensile strength and Rockwell C33 hardness. The zinc yellow-chromate plating provides corrosion resistance while maintaining compliance with industrial fastener requirements for heavy-duty applications.