S-91268A320 1 1/4"-12 x 4" 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 150,000 psi tensile strength for reliable performance in high-stress applications.
• Superior wear and deformation resistance due to Rockwell C33 hardness, ensuring long-term durability.
• Precise and secure fastening with Class 2A thread fit, reducing the risk of cross-threading and loosening.
• Optimized for heavy-duty industrial use with a Grade 8 steel construction and ASME B18.2.1 compliance.
• Easy installation and removal using standard tools thanks to the external hex drive and 1 7/8" head width.
• Enhanced thread engagement in tough materials with fine UNF threading and partial threading design.
• Safe for regulated environments with full compliance to RoHS 3 and REACH standards.

Professional Applications & Engineering Value

This Grade 8 steel hex head screw is engineered to address critical challenges in heavy machinery, structural assemblies, and automotive systems where vibration and dynamic loads are common. The 1 1/4"-12 UNF fine thread provides superior resistance to loosening under stress, while the partially threaded shank allows for controlled clamp force distribution. Made from high-strength steel and heat-treated to Rockwell C33 hardness, it prevents stripping and withstands extreme tension, making it ideal for industrial fastening solutions that demand reliability and longevity. Its compliance with ASME B18.2.1 ensures interchangeability and performance consistency in professional settings.

Specification Summary & Compliance

This screw adheres to Class 2A thread fit tolerances for precise assembly, with a UNF thread type and fine thread spacing. It meets ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in environmentally sensitive applications.