S-91257A550 1/4"-20 x 2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Maximum load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for critical structural applications
• Superior corrosion protection through zinc yellow-chromate plating that withstands harsh industrial environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit ensuring reliable installation and vibration resistance
• Enhanced torque transmission via external hex drive design that prevents tool slippage during high-torque applications
• Precision manufacturing to ASME B18.2.1 and SAE J429 standards guaranteeing consistent quality and dimensional accuracy
• Partial threading design providing both gripping strength in threaded sections and shear resistance in unthreaded areas
• Regulatory compliance with RoHS 3 and REACH environmental standards for safe, sustainable industrial use

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver exceptional performance where failure is not an option. The steel construction with Rockwell C33 hardness provides the perfect balance between strength and ductility, resisting both static overload and dynamic fatigue. The zinc yellow-chromate plating creates a robust barrier against corrosion in demanding environments from manufacturing facilities to outdoor equipment. With 1/4"-20 UNC coarse threading and partial threading design, these fasteners offer superior clamping force in assembly applications while maintaining structural integrity under vibration and shock loads. The external hex drive ensures reliable torque application, making them ideal for machinery, structural steel connections, and heavy equipment where precise installation is critical.

Specification Summary & Compliance

Manufactured to exacting ASME B18.2.1 and SAE J429 specifications, these hex head screws feature Class 2A thread fit for optimal assembly clearance while maintaining strength. The 1/4"-20 UNC coarse thread with 2" length and 3/4" minimum thread length provides standardized dimensional consistency. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental responsibility and workplace safety standards are met.