S-91257A634 3/8"-16 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 150,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
• Optimized torque transmission through external hex drive design for secure installation and removal
• Enhanced thread engagement with Class 2A thread fit ensuring precise assembly and vibration resistance
• Reduced installation time through coarse UNC threading that facilitates quicker fastening operations
• Controlled clamping force with partial threading design that prevents over-tightening in critical joints
• Industry compliance assurance meeting ASME, SAE, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

These Grade 8 hex head screws deliver exceptional engineering value in heavy-duty industrial applications where failure is not an option. The zinc yellow-chromate plated steel construction provides superior corrosion protection for machinery, structural frameworks, and equipment exposed to demanding environmental conditions. The 3/8"-16 UNC coarse threading combined with partial threading design ensures optimal stress distribution while preventing thread stripping in high-vibration environments. With Rockwell C33 hardness and 150,000 psi tensile strength, these fasteners maintain integrity under extreme loads, making them ideal for construction equipment, automotive assemblies, and industrial machinery where reliability and safety are paramount. The external hex drive allows for high-torque installation, ensuring secure fastening in critical applications.

Specification Summary & Compliance

This high-strength fastener features precision Class 2A thread fit with 3/8"-16 UNC coarse threading and partial threading configuration. Manufactured to exacting ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and performance reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, confirming its suitability for global industrial applications while meeting stringent safety and environmental standards.