S-91236A564 1/4"-20 x 5 1/2" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating for extended service life in demanding industrial environments
• Exceptional tensile strength of 60,000 PSI ensures reliable performance under heavy loads and vibration
• Optimized torque transmission through external hex drive design for secure installation and removal
• Precision thread engagement with Class 2A fit and UNC coarse threads for faster assembly and reduced cross-threading risk
• Enhanced material durability from Rockwell B69 hardness steel that withstands mechanical stress and wear
• Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for quality and environmental safety
• Strategic partial threading provides both gripping power and clearance where needed in structural applications

Professional Applications & Engineering Value

This 1/4"-20 UNC hex head screw delivers critical engineering solutions for industrial assembly challenges. The steel construction with zinc plating combats corrosion in manufacturing facilities, outdoor equipment, and structural frameworks where environmental exposure is a concern. The coarse thread design enables rapid installation in various materials while maintaining superior holding power. With partial threading along its 5 1/2" length, this fastener provides optimal clamp load distribution while allowing unthreaded sections to function as precision guides or clearance in machinery assemblies. The external hex drive accommodates standard tools for efficient maintenance operations, making it ideal for heavy-duty applications requiring repeated disassembly and reassembly.

Specification Summary & Compliance

Manufactured to ASME B18.2.1 specifications using ASTM A307 steel, this hex head screw maintains precise Class 2A thread fit tolerances for consistent performance. The UNC coarse thread (1/4"-20) with right-hand direction and 3/4" minimum thread length ensures reliable engagement. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms environmental responsibility, while the 60,000 PSI tensile strength and Rockwell B69 hardness validate mechanical reliability for industrial fastening requirements.