S-90211A224 1/4"-20 x 1" SAE J429 Left-Hand Threaded High-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with Grade 8 rating and 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 industrial environments
• Precise thread engagement with Class 3A thread fit ensuring secure fastening and vibration resistance
• Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated use
• Left-hand threading design for specialized applications where reverse rotation prevents loosening
• Optimized drive efficiency with external hex head design allowing high torque application and easy installation
• Industry-standard compliance meeting SAE J429 specifications for guaranteed quality and interchangeability

Professional Applications & Engineering Value

Engineered for demanding industrial scenarios, these Grade 8 hex head screws deliver critical performance where standard fasteners fail. The left-hand UNC coarse threading provides specialized solutions for rotating equipment where conventional right-hand threads would loosen under counter-clockwise motion. The zinc yellow-chromate plating creates a robust barrier against oxidation and chemical exposure, making these steel fasteners ideal for automotive assemblies, heavy machinery, and outdoor infrastructure. With fully threaded design and external hex drive, installation efficiency is maximized while maintaining consistent clamping force across the entire 1-inch length. These screws address common industrial pain points including vibration-induced failure, corrosion degradation, and high-torque requirements.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit tolerance for superior thread engagement. The 1/4"-20 UNC coarse thread specification ensures compatibility with standard components. These hex head screws fully comply with SAE J429 mechanical and material requirements for Grade 8 fasteners. The manufacturing process adheres to industry standards for dimensional accuracy, mechanical properties, and surface treatment consistency.