S-91381A534 1/4"-20 x 5/16" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in harsh industrial environments
• Precise Class 3A thread fit ensures tight tolerances and reliable, vibration-resistant fastening
• Brass soft tip design prevents damage to mating surfaces while maintaining secure component positioning
• Hex drive compatibility allows for high-torque installation with standard 1/8" hex tools
• Rockwell C28 hardness rating provides excellent durability and resistance to wear under heavy loads
• Headless configuration enables flush mounting in space-constrained applications
• Coarse UNC threading facilitates quick installation and removal in production environments

Professional Applications & Engineering Value

This black-oxide alloy steel set screw delivers exceptional engineering value in demanding industrial applications where component security and surface protection are critical. The combination of Class 3A UNC threads and Rockwell C28 hardness ensures reliable performance in high-vibration environments such as machinery, automotive assemblies, and precision equipment. The brass soft tip is specifically engineered to prevent marring or damaging expensive components while maintaining positive positioning, making it ideal for securing gears, pulleys, and collars on shafts. The headless hex drive design allows for flush installation in confined spaces, while the coarse 1/4"-20 thread provides rapid assembly and disassembly in manufacturing and maintenance operations. This set screw solves common industrial challenges by offering corrosion resistance, surface protection, and vibration-resistant fastening in a single precision component.

Specification Summary & Compliance

This precision fastener features 1/4"-20 UNC Class 3A threads with coarse spacing, manufactured to exacting dimensional standards. The black-oxide alloy steel construction meets ASME B18.3 specifications for set screws, ensuring dimensional accuracy and performance reliability. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations confirms environmental responsibility and material safety. The 5/16" length and 1/8" hex drive provide standardized installation compatibility across industrial applications.