S-91268A254 5/16"-18 x 6" 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 durability and wear resistance thanks to Rockwell C33 hardness, providing a long service life in harsh industrial environments.
• Secure and easy installation with an external hex drive and 1/2" head width, allowing for high torque application with standard tools.
• Optimized for quick assembly featuring coarse UNC threads and a Class 2A thread fit, which resist vibration loosening and reduce cross-threading risks.
• Versatile partial threading design with a 7/8" minimum thread length on a 6" shank, offering flexibility for applications requiring both clamped and unthreaded sections.
• Compliance with major industry standards including ASME B18.2.1 and SAE J429, guaranteeing consistent quality and interchangeability.
• Environmentally responsible manufacturing with RoHS 3 and REACH compliance, ensuring safety and regulatory adherence for global supply chains.

Professional Applications & Engineering Value

This Grade 8 steel hex head screw is engineered to solve critical challenges in heavy machinery, construction, and automotive assemblies where failure is not an option. The partially threaded design provides a non-threaded shoulder for precise alignment and shear resistance, while the coarse UNC thread ensures rapid installation and superior holding power in wood, metal, and composite materials. The external hex drive and high tensile strength allow it to withstand extreme vibrational loads and dynamic forces, making it an ideal industrial strength screw for structural frames, equipment mounting, and high-stress connections. Its compliance with ASME B18.2.1 and material properties deliver predictable performance, reducing maintenance downtime and enhancing project reliability.

Specification Summary & Compliance

This fastener adheres to precise dimensional and performance criteria, including a Class 2A thread fit for consistent assembly and UNC coarse threading (5/16"-18). It is manufactured in accordance with ASME B18.2.1 and SAE J429 standards for Grade 8 fasteners. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety requirements for industrial use.