S-91257A685 7/16"-14 x 4" 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 the fastener's service life in harsh industrial environments.
• High hardness for wear resistance with a Rockwell C33 rating, reducing thread deformation and maintaining integrity during installation and use.
• Optimized for quick assembly featuring coarse UNC threads and an external hex drive head, allowing for efficient installation with standard tools.
• Reliable thread engagement and fit due to the Class 2A thread fit, minimizing the risk of cross-threading and ensuring consistent clamping force.
• Versatile partial threading design offering a non-threaded shank for precise shear load distribution and alignment in structural connections.
• Compliance with major industry standards including ASME B18.2.1 and SAE J429, guaranteeing interchangeability and performance reliability.

Professional Applications & Engineering Value

This Grade 8 Hex Head Screw is engineered to solve critical challenges in heavy machinery, construction, and automotive assemblies where failure is not an option. The steel construction, combined with the zinc yellow-chromate plating, provides a robust barrier against rust and chemical exposure, significantly reducing maintenance downtime. The 7/16"-14 UNC coarse thread and external hex drive facilitate rapid installation in high-vibration environments, preventing loosening. Its 150,000 psi tensile strength and Rockwell C33 hardness ensure it can handle extreme tensile and shear loads, making it ideal for bolting critical frames, engines, and structural supports. The partially threaded design allows the unthreaded portion to act as a precision dowel, improving joint stability and load distribution in dynamic applications.

Specification Summary & Compliance

This fastener adheres to precise dimensional tolerances with a Class 2A thread fit and UNC thread standard for consistent performance. It is manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, ensuring mechanical properties and interchangeability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free from hazardous substances and safe for use in regulated industries.