S-91247A374 1/2"-20 x 8" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• High tensile strength of 120,000 psi ensures reliable performance in demanding industrial applications and prevents fastener failure under heavy loads
• Zinc plating surface treatment provides excellent corrosion resistance, extending service life in various environmental conditions
• Grade 5 classification with Rockwell C25 hardness offers optimal balance of strength and durability for repeated use in structural applications
• 1/2"-20 UNF fine thread design with Class 2A fit delivers superior vibration resistance and precise engagement in critical assemblies
• External hex drive with 3/4" head width allows for high torque application and easy installation with standard tools
• Partially threaded 8" length configuration provides unthreaded shank for shear strength while maintaining sufficient thread engagement
• Compliance with ASME B18.2.1, RoHS 3, and REACH standards guarantees quality assurance and regulatory compliance for global industrial use

Professional Applications & Engineering Value

This Grade 5 hex head screw addresses critical engineering challenges in heavy machinery, construction equipment, and structural frameworks where vibration resistance and load-bearing capacity are paramount. The 1/2"-20 UNF fine thread configuration maintains clamping force under dynamic loads, while the partially threaded design ensures optimal stress distribution across the fastener length. The zinc plated finish on steel construction provides essential corrosion protection for outdoor and industrial environments, significantly reducing maintenance frequency and replacement costs. Engineered to ASME B18.2.1 specifications and SAE J429 standards, this fastener delivers consistent performance in automotive, manufacturing, and infrastructure applications where reliability cannot be compromised.

Specification Summary & Compliance

This 8-inch hex head screw features precise Class 2A thread fit tolerance per UNF standards, ensuring consistent engagement and proper mating with corresponding nuts. Manufacturing complies with ASME B18.2.1 dimensional requirements and SAE J429 material specifications for Grade 5 fasteners. The product is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations regarding chemical safety, making it suitable for international industrial markets and environmentally conscious applications.