S-90211A236 1/4"-20 x 3" SAE J429 Left-Hand Threaded High-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum Load Capacity – Grade 8 classification with 150,000 psi tensile strength ensures reliable performance in high-stress applications
• Superior Corrosion Protection – Zinc yellow-chromate plating provides excellent resistance against rust and environmental degradation
• Precision Thread Engagement – Class 3A thread fit guarantees tight tolerances and secure fastening in critical assemblies
• Enhanced Durability – Rockwell C33 hardness maintains structural integrity under repeated loading and vibration
• Left-Hand Thread Security – Reverse threading direction prevents loosening in rotating machinery and specialized equipment
• Optimized Drive Efficiency – External hex head design allows high torque application with standard tools
• Full Thread Coverage – 3" fully threaded length provides maximum grip and adjustment flexibility

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these Grade 8 hex head screws deliver exceptional reliability where failure is not an option. The left-hand UNC coarse thread configuration specifically addresses applications involving counter-rotational forces, preventing unintended disassembly in machinery, conveyor systems, and power transmission equipment. The zinc yellow-chromate plated steel construction creates a robust barrier against corrosion in manufacturing facilities, outdoor installations, and high-humidity operations. With fully threaded design and Class 3A thread fit, these fasteners maintain consistent clamping force across the entire engagement length, eliminating weak points in structural connections and heavy equipment assemblies where vibration resistance is critical.

Specification Summary & Compliance

This 1/4"-20 x 3" left hand hex head screw features UNC coarse thread with precision Class 3A thread fit for superior engagement. Manufactured from high-strength steel with Rockwell C33 hardness and 150,000 psi tensile strength meeting Grade 8 requirements. Complies with SAE J429 specifications for dimensional accuracy and mechanical properties. The zinc yellow-chromate plating provides corrosion protection while maintaining compliance with industry standards for heavy-duty fastening applications.