S-91286A254 3/8"-24 x 2 1/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional strength for demanding applications with Grade 8 classification and 150,000 psi tensile strength, ensuring reliable performance under high stress.
• Superior corrosion resistance provided by the zinc-flake coating, extending the service life of the fastener in harsh industrial environments.
• Optimized thread engagement with a Class 2A thread fit and fine UNF thread spacing, offering precise assembly and reduced risk of cross-threading.
• High durability and wear resistance from Rockwell C33 hardness, maintaining structural integrity through repeated use and high-torque installation.
• Efficient installation and removal with an external hex drive and hex head design, allowing for quick, secure fastening with standard tools.
• Versatile partial threading enabling effective clamping on a wide range of material thicknesses without compromising grip strength.
• Compliance with major industry standards including ASME B18.2.1 and SAE J429, ensuring consistent quality and interchangeability.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial and construction applications. The zinc-flake coated steel construction provides robust protection against corrosion, making it ideal for outdoor machinery, automotive assemblies, and structural frameworks exposed to moisture and chemicals. The 3/8"-24 UNF fine thread design ensures superior resistance to vibration loosening, a common issue in dynamic load environments. With a partially threaded shank, it offers precise unthreaded grip length for secure joint clamping, reducing the risk of material damage. Its high 150,000 psi tensile strength and Rockwell C33 hardness guarantee that it withstands extreme mechanical stresses, providing long-term reliability in critical fastening points where failure is not an option.

Specification Summary & Compliance

This fastener adheres to precise dimensional standards with a Class 2A thread fit and UNF fine thread spacing, ensuring consistent performance and compatibility. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, guaranteeing uniformity and reliability. Additionally, the product meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, confirming its suitability for use in environmentally conscious and regulated industries.