S-90211A226 1/4"-20 x 1 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 environments
• Superior corrosion resistance through zinc yellow-chromate plating that protects against harsh industrial conditions
• Precise thread engagement with Class 3A fit ensuring secure fastening and vibration resistance
• Optimized for reverse-thread applications using left-hand UNC coarse threads for specialized mechanical assemblies
• Maximum installation torque capability through external hex drive design and Rockwell C33 hardness
• Full-length threading provides consistent grip along the entire 1 1/4" length for uniform clamping force
• Industry-standard compliance meeting SAE J429 specifications for guaranteed quality and interchangeability

Professional Applications & Engineering Value

Engineered for demanding industrial applications where reverse rotation or counter-clockwise tightening is required, these Grade 8 hex head screws deliver exceptional performance in machinery, automotive, and heavy equipment assemblies. The left-hand UNC coarse thread design prevents loosening in rotating systems that turn counter-clockwise, while the zinc yellow-chromate plated steel construction withstands corrosive environments without compromising the 150,000 psi tensile strength. The combination of external hex drive and fully threaded design ensures maximum torque application and uniform stress distribution, making these industrial screws ideal for critical joints in vibration-prone equipment where failure is not an option.

Specification Summary & Compliance

This heavy-duty fastener features precise 1/4"-20 UNC left-hand coarse threads with Class 3A thread fit for superior engagement and meets SAE J429 specifications for Grade 8 mechanical properties. The manufacturing process ensures dimensional accuracy with Rockwell C33 hardness and 150,000 psi tensile strength certification. The zinc yellow-chromate plating provides corrosion protection while maintaining compliance with industrial standards for mechanical fasteners used in critical applications.