S-91257A820 5/8"-11 x 7" 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 yellow-chromate plating, extending service life in harsh industrial environments.
• Optimized for high-torque assembly thanks to the external hex head design, allowing for secure and efficient installation with standard tools.
• Reliable coarse threading (UNC) with Class 2A fit for easier engagement and reduced risk of cross-threading in heavy-duty assemblies.
• Enhanced durability and wear resistance from Rockwell C33 hardness, maintaining fastener integrity through repeated use.
• Versatile partial threading offering a non-threaded shank for precise clamping in structural and machinery applications.
• Compliance with major industry standards including ASME B18.2.1 and environmental regulations like RoHS 3 and REACH, ensuring quality and safety.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial applications, such as construction, machinery assembly, and structural frameworks. The steel material combined with a zinc yellow-chromate plating provides robust protection against corrosion, which is essential for outdoor or high-moisture environments. The 5/8"-11 UNC coarse thread and Class 2A thread fit ensure quick, secure fastening with minimal risk of stripping, while the partially threaded design allows for precise load distribution and vibration resistance. By meeting ASME B18.2.1 specifications, these screws deliver consistent performance in high-stress scenarios, reducing downtime and maintenance costs for B2B clients.

Specification Summary & Compliance

This fastener adheres to precise dimensional standards, including a Class 2A thread fit and UNC coarse threading with a 5/8"-11 thread size. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications for Grade 8 fasteners. Additionally, the product is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring it meets stringent environmental and safety regulations for industrial use.