S-91257A560 1/4"-20 x 5" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for reliable performance in high-stress environments
• Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh industrial conditions
• Optimized thread engagement with UNC coarse thread design and Class 2A fit ensuring secure fastening and vibration resistance
• Enhanced installation efficiency featuring external hex drive and standard 1/4"-20 thread size for quick assembly with common tools
• Precision engineering compliance meeting ASME B18.2.1 and SAE J429 specifications for consistent quality and interchangeability
• Strategic partial threading on the 5" length providing both threaded and unthreaded sections for versatile clamping applications
• Environmental regulation adherence with RoHS 3 and REACH compliance for safe use across global markets

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these Grade 8 hex head screws deliver exceptional mechanical performance where failure is not an option. The Rockwell C33 hardness rating combined with 150,000 psi tensile strength ensures these fasteners withstand extreme tension and shear forces in heavy machinery, structural steel connections, and automotive assemblies. The zinc yellow-chromate plating provides superior corrosion resistance, making them ideal for outdoor equipment, marine environments, and manufacturing facilities where moisture and chemicals are present. The 1/4"-20 UNC coarse thread design offers rapid installation and reliable holding power, while the partially threaded configuration allows for precise clamping force distribution across the 5" length. These industrial-grade fasteners solve critical challenges in construction, mining, and transportation sectors where vibration resistance, durability, and consistent performance are paramount.

Specification Summary & Compliance

This high-strength hex head screw features precise Class 2A thread fit with 1/4"-20 UNC coarse thread specifications and 3/4" minimum thread length. Manufactured to exacting ASME B18.2.1 dimensional standards and SAE J429 material requirements, ensuring mechanical properties and interchangeability. The fastener is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations for chemical safety, making it suitable for international industrial applications and environmentally conscious procurement specifications.