S-91251A780 1 3/8"-6 x 12" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under extreme loads and prevents fastener failure in demanding applications.
• Superior corrosion resistance from the Black-Oxide finish on Alloy Steel, extending service life and reducing maintenance in harsh industrial environments.
• Precise hex drive engagement with a 1" drive size and standard socket head profile allows for high torque application and reduces the risk of tool slippage.
• Optimized for high-strength assembly with a Rockwell C37 hardness, providing excellent wear resistance and durability.
• Versatile coarse UNC thread (1 3/8"-6) with Class 2A fit enables faster installation and reliable performance in a wide range of materials.
• Efficient partially threaded design on a 12" length provides a strong clamping force on the unthreaded shank while allowing for nut use on the threaded portion.
• Guaranteed quality and compliance meeting ASTM A574 specifications, RoHS 3, and REACH, ensuring material consistency and environmental safety for global projects.

Professional Applications & Engineering Value

This Socket Head Cap Screw is engineered to solve critical challenges in heavy machinery, construction, and large-scale structural fabrication. The Black-Oxide Alloy Steel construction provides a robust barrier against rust and corrosion, which is vital for equipment exposed to moisture or chemicals. Its coarse UNC thread and Class 2A thread fit ensure quick, secure fastening in thick metal plates or castings, reducing assembly time while maintaining joint integrity. The partially threaded 12-inch length is ideal for applications requiring a non-threaded bearing surface, such as in precision alignment systems or where a smooth shank must pass through a clearance hole, preventing thread damage and distributing stress effectively. This combination of high tensile strength and precise engineering makes it a reliable choice for high-stress industrial fastening tasks.

Specification Summary & Compliance

This screw features a 1 3/8"-6 UNC coarse thread with a Class 2A thread fit for standard clearance and reliable engagement. Manufactured to ASTM A574 specification, ensuring consistent quality and performance for socket head cap screws. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free from hazardous substances and suitable for use in regulated markets.