S-91257A678 7/16"-14 x 2 1/4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for reliable performance in high-stress applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh industrial environments
• Optimal hardness and durability with Rockwell C33 rating, ensuring minimal wear and deformation under heavy use
• Precise thread engagement with Class 2A fit and UNC coarse threading for easier assembly and reduced cross-threading risk
• Secure fastening capability through external hex drive design that accommodates standard tools and prevents stripping
• Partial threading design that provides both gripping strength and clearance where needed in assembled components
• Full regulatory compliance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for quality assurance

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver critical engineering solutions where high tensile strength and corrosion resistance are paramount. The zinc yellow-chromate plated finish provides exceptional protection against oxidation and chemical exposure in demanding environments such as heavy machinery, construction equipment, and automotive assemblies. The 7/16"-14 UNC coarse thread configuration ensures rapid installation and reliable holding power in steel-to-steel applications, while the partially threaded design allows for precise clamp load distribution. Manufactured from high-grade steel and heat-treated to achieve Rockwell C33 hardness, these hex head screws maintain dimensional stability under extreme vibration and dynamic loads, making them ideal for structural connections, industrial machinery, and equipment manufacturing where failure is not an option.

Specification Summary & Compliance

This 2 1/4" length hex head screw features precise Class 2A thread fit tolerances with 7/16"-14 UNC coarse threading and partial threading configuration. Manufactured to exacting ASME B18.2.1 and SAE J429 specifications for dimensional accuracy and performance reliability. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across various industrial applications while meeting international quality standards for Grade 8 mechanical properties.