S-90019A250 5/16"-18 x 3/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Thread-Locking Hex Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant performance with permanent nylon patch thread locking that prevents loosening under extreme conditions
• Exceptional strength and durability with Grade 8 classification and 150,000 psi tensile strength for heavy-duty applications
• Superior corrosion protection through zinc yellow-chromate plating that extends service life in harsh environments
• Wide temperature tolerance from -55° to 250°F maintains locking performance across diverse operating conditions
• Precise thread engagement with Class 2A UNC coarse threads ensuring reliable installation and consistent clamping force
• Optimized drive efficiency through external hex head design providing maximum torque transfer during installation
• Industry compliance assurance meeting ASME B18.2.1 and SAE J429 specifications for quality and reliability

Professional Applications & Engineering Value

These Grade 8 hex head screws with nylon patch thread locking deliver critical vibration resistance in demanding industrial environments. The zinc yellow-chromate plated steel construction provides superior corrosion protection while maintaining structural integrity under heavy loads. Engineered with UNC coarse threads and Class 2A fit, these fasteners ensure reliable installation in construction equipment, automotive assemblies, and heavy machinery where vibration-induced loosening can compromise safety. The combination of 150,000 psi tensile strength and Rockwell C33 hardness makes them ideal for structural applications requiring both high strength and fatigue resistance. The external hex drive design facilitates efficient installation with standard tools, reducing assembly time while maintaining consistent clamping force in critical joints.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit and UNC coarse threading (5/16"-18). These fully threaded screws comply with ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and mechanical properties. The nylon patch thread locker maintains effectiveness across the specified temperature range of -55° to 250°F. Material composition and plating processes meet industry standards for heavy-duty fasteners, providing reliable performance in construction, automotive, and industrial applications where quality assurance and specification compliance are paramount.