S-91257A535 1/4"-20 x 1 3/8" 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 demanding applications
• Superior corrosion resistance through zinc yellow-chromate plating that extends service life in harsh environments
• Optimized torque transmission with external hex drive design for secure installation and removal
• Enhanced durability with Rockwell C33 hardness that maintains structural integrity under heavy stress
• Precision threading compatibility with Class 2A UNC coarse threads ensuring consistent engagement
• Versatile partial threading design providing both gripping strength and adjustment flexibility
• Industry-standard compliance meeting ASME B18.2.1 and SAE J429 specifications for quality assurance

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance in construction equipment, automotive assemblies, and machinery manufacturing. The zinc yellow-chromate plated steel construction provides superior corrosion protection in environments exposed to moisture and chemicals, while the 1/4"-20 UNC coarse threading ensures rapid installation and reliable fastening in structural components. The external hex drive design allows for high-torque application without stripping, and the partial threading offers optimal clamp load distribution. These high-strength bolts are specifically designed to withstand extreme vibration and dynamic loads, making them ideal for critical connections where failure is not an option.

Specification Summary & Compliance

This 1/4"-20 x 1-3/8" hex head screw features precision Class 2A thread fit with UNC coarse threading standards, ensuring consistent engagement and reliable performance. Manufactured to exacting ASME B18.2.1 dimensional specifications and SAE J429 Grade 8 mechanical requirements, these fasteners deliver guaranteed 150,000 PSI tensile strength and Rockwell C33 hardness. The product meets industry standards for dimensional accuracy and mechanical properties, providing engineers and procurement specialists with certified performance data for critical application specifications.