S-91236A551 1/4"-20 x 2 1/4" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating that protects against rust and extends service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable performance under heavy loads and prevents fastener failure
• Rockwell B69 hardness provides excellent durability and resistance to wear during installation and use
• External hex drive design allows for easy installation and high torque application with standard tools
• Class 2A thread fit offers consistent, reliable engagement for simplified assembly and reduced cross-threading risks
• Partially threaded shank provides unthreaded grip length for better clamping force distribution in structural applications
• Full compliance with industry standards including ASME B18.2.1, RoHS 3, and REACH for quality assurance and regulatory acceptance

Professional Applications & Engineering Value

This 1/4"-20 UNC hex head screw delivers exceptional engineering value through its steel construction and zinc plating, specifically designed to address common industrial challenges. The coarse thread configuration provides superior holding power in various materials, while the partially threaded design ensures optimal clamping force distribution in structural assemblies and machinery. With its external hex drive and Class 2A thread fit, this fastener enables quick, reliable installation in manufacturing, construction, and equipment maintenance applications. The combination of 60,000 psi tensile strength and Rockwell B69 hardness makes it ideal for heavy-duty applications where vibration resistance and long-term reliability are critical, reducing maintenance frequency and downtime in industrial operations.

Specification Summary & Compliance

This hex head screw features precise Class 2A thread fit tolerances and UNC coarse threading with 1/4"-20 thread size. Manufactured to ASME B18.2.1 specifications using ASTM A307 grade steel, it ensures dimensional accuracy and mechanical consistency. The product maintains full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and regulatory acceptance for global industrial applications.