S-91247A357 1/2"-20 x 2 1/4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior tensile strength with 120,000 psi rating ensures reliable performance in high-stress industrial and construction applications
• Enhanced corrosion resistance through zinc plating protects against environmental degradation in demanding conditions
• Precision UNF fine threading (1/2"-20) provides superior vibration resistance and secure fastening in critical assemblies
• Grade 5 strength classification with Rockwell C25 hardness delivers optimal balance of durability and machinability
• External hex drive design with 3/4" head width enables high-torque installation using standard tools
• Class 2A thread fit ensures smooth assembly and consistent performance across production runs
• Partially threaded construction allows for precise clamping force distribution in multi-material applications

Professional Applications & Engineering Value

This Grade 5 hex head screw delivers exceptional engineering value through its zinc plated steel construction and UNF fine thread design, specifically engineered to address common industrial challenges. The combination of 120,000 psi tensile strength and Rockwell C25 hardness provides reliable performance in heavy machinery, structural steel connections, and equipment manufacturing where vibration resistance and load-bearing capacity are critical. The partially threaded configuration allows for optimal stress distribution, preventing material deformation in assembly applications involving multiple substrates. The external hex drive facilitates high-torque installation in confined spaces, while the fine thread pitch maintains secure fastening under dynamic loading conditions common in industrial environments.

Specification Summary & Compliance

This 1/2"-20 hex head screw features precise Class 2A thread fit tolerances and UNF fine thread specifications compliant with ASME B18.2.1 and SAE J429 Grade 5 standards. The fastener maintains dimensional accuracy with a 2-1/4" length and 1-1/4" minimum thread length. Manufacturing compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial applications requiring strict material and safety standards.