S-91257A643 3/8"-16 x 4 3/4" 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 through zinc yellow-chromate plating that protects against rust and extends service life
• Optimized installation efficiency with external hex drive design providing secure tool engagement and torque transmission
• Enhanced thread reliability with UNC coarse threading and Class 2A fit ensuring consistent fastening in various materials
• Reduced weight without compromising strength through partial threading design while maintaining full shank diameter
• Guaranteed material integrity with Rockwell C33 hardness and Grade 8 certification for consistent mechanical properties
• Industry-standard compatibility meeting ASME B18.2.1 and SAE J429 specifications for seamless integration into existing systems

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance where failure is not an option. The steel construction combined with zinc yellow-chromate plating provides critical corrosion protection in harsh environments, from manufacturing equipment to structural assemblies. The 3/8"-16 UNC coarse thread configuration ensures rapid installation and superior holding power in both metal and composite materials, while the partial threading design optimizes clamp load distribution. These industrial fasteners solve critical engineering challenges by maintaining 150,000 PSI tensile strength under extreme vibration and dynamic loading conditions, making them ideal for machinery, construction, and transportation applications demanding high-strength bolting solutions.

Specification Summary & Compliance

This heavy-duty fastener features precision Class 2A thread fit with UNC coarse threading standards, ensuring consistent engagement and reliable performance. Manufactured to exacting ASME B18.2.1 and SAE J429 specifications, these hex head screws maintain dimensional accuracy and mechanical properties throughout their service life. The product complies with industry standards for Grade 8 strength classification, delivering guaranteed 150,000 PSI tensile strength and Rockwell C33 hardness for engineering applications requiring certified performance metrics.