S-91247A411 9/16"-18 x 3 1/2" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with Grade 5 steel construction and 120,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through zinc plating, extending service life in harsh industrial environments
• Precise thread engagement with UNF fine threading and Class 2A fit ensuring vibration resistance and secure fastening
• Optimized torque transmission via external hex drive and 13/16" head width for efficient installation with standard tools
• Enhanced durability from Rockwell C25 hardness, maintaining structural integrity under repeated stress
• Versatile partial threading design allowing unthreaded shank sections for improved shear strength
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This Grade 5 steel hex head screw delivers critical engineering solutions for heavy machinery, structural assemblies, and equipment manufacturing where vibration resistance and long-term reliability are paramount. The 9/16"-18 UNF fine threading provides superior clamping force distribution compared to coarse threads, while the zinc plating creates a sacrificial barrier against oxidation in demanding environments. The partially threaded design allows the unthreaded shank to bear shear loads directly, preventing thread damage in dynamic applications. With external hex drive compatibility, installers achieve optimal torque application using standard industrial tools, reducing assembly time and improving joint integrity across automotive, construction, and manufacturing sectors.

Specification Summary & Compliance

Manufactured to Class 2A thread fit tolerances with UNF fine thread specifications (9/16"-18) and right-hand threading orientation. Complies with ASME B18.2.1 dimensional standards and SAE J429 material specifications for Grade 5 fasteners. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance. Physical properties include Rockwell C25 hardness, 120,000 psi minimum tensile strength, and 3 1/2" length with 1 3/8" minimum thread length.