S-91286A418 5/8"-11 x 4 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 PSI ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the zinc-flake coating extends service life in harsh environments, minimizing maintenance and replacement costs.
• High hardness rating (Rockwell C33) provides excellent wear resistance, maintaining structural integrity under repeated loads.
• Partially threaded design offers optimal grip and clamping force, ideal for applications requiring secure fastening without full threading.
• Coarse UNC threads enable quick installation and removal, improving assembly efficiency in maintenance and production lines.
• Class 2A thread fit ensures consistent, reliable engagement with nuts and tapped holes, reducing assembly errors and rework.
• External hex drive allows for high-torque application with standard tools, facilitating secure tightening in confined spaces.

Professional Applications & Engineering Value

This Grade 8 hex head screw is engineered to address critical challenges in heavy-duty industrial settings, such as machinery assembly, structural frameworks, and automotive systems. The zinc-flake coated steel construction provides robust protection against corrosion, essential for outdoor or chemically exposed environments, while the 150,000 PSI tensile strength and Rockwell C33 hardness ensure durability under dynamic loads and vibrations. The partially threaded and coarse UNC thread design enhances grip and reduces the risk of loosening, making it ideal for applications where reliability and safety are paramount. Compliant with ASME B18.2.1 standards, it delivers consistent performance in construction, manufacturing, and equipment maintenance, minimizing downtime and enhancing operational efficiency.

Specification Summary & Compliance

This fastener adheres to precise dimensional standards, including a Class 2A thread fit for consistent assembly and UNC coarse threads with a size of 5/8"-11. It meets ASME B18.2.1 and SAE J429 specifications for quality and performance. Additionally, it is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and suitability for global industrial use.