S-90211A339 1/2"-13 x 2 1/4" SAE J429 Left-Hand Threaded High-Strength 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 through zinc yellow-chromate plating that extends service life in demanding environments
• Precise thread engagement with Class 3A fit and UNC coarse spacing ensuring secure fastening and vibration resistance
• Maximum torque transmission via external hex drive design that prevents tool slippage during installation
• Enhanced durability from Rockwell C33 hardness that maintains structural integrity under repeated stress
• Industry-standard compliance meeting SAE J429 specifications for guaranteed quality and interchangeability
• Left-hand threading advantage providing specialized solutions for counter-rotational systems and safety-critical assemblies

Professional Applications & Engineering Value

This Grade 8 heavy-duty hex head screw delivers critical engineering solutions where conventional fasteners fail. The left-hand UNC coarse thread design specifically addresses applications requiring reverse-threading security, such as rotating machinery where standard right-hand threads would loosen under operational forces. The zinc yellow-chromate plating creates a protective barrier against corrosion in industrial environments exposed to moisture, chemicals, and temperature variations. With fully threaded construction and Class 3A thread fit, these screws maintain consistent clamping force across the entire 2 1/4" length, preventing joint failure in structural assemblies, heavy equipment, and automotive systems where vibration resistance is paramount. The combination of 150,000 PSI tensile strength and Rockwell C33 hardness ensures these fasteners withstand extreme mechanical stresses without deformation or fatigue failure.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit tolerance for superior engagement. Thread specifications conform to 1/2"-13 UNC coarse thread standards with left-hand direction. Full compliance with SAE J429 specifications for Grade 8 fasteners, ensuring consistent mechanical properties and performance characteristics. The zinc yellow-chromate plating provides corrosion protection while maintaining dimensional accuracy. Manufacturing processes adhere to industry quality standards for high-strength industrial fasteners.