S-91375A557 1/4"-28 x 5/16" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in demanding industrial environments
• Exceptional thread precision with Class 3A fit ensuring reliable, vibration-resistant fastening in critical assemblies
• High-strength durability from alloy steel construction with Rockwell C45 hardness for heavy-duty applications
• Secure non-slip installation through 1/8" hex drive design allowing high torque application without head interference
• Enhanced grip performance with cup point tip providing superior biting action on shaft surfaces
• Industry-standard compatibility with UNF fine threads (1/4"-28) for precise equipment adjustments and positioning
• Regulatory compliance assurance meeting ASME B18.3, ASTM F912, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

This black-oxide alloy steel set screw delivers critical engineering solutions for industrial machinery, automotive components, and precision equipment where vibration resistance and positioning accuracy are paramount. The headless design with 1/8" hex drive enables flush mounting in confined spaces while maintaining high torque capability. The Class 3A thread fit combined with UNF fine threading (1/4"-28) ensures minimal backlash in adjustable assemblies, preventing gradual loosening under dynamic loads. The cup point tip creates permanent indentations on shaft surfaces, providing superior resistance to rotational forces in pulley systems, gears, and coupling applications. The corrosion-resistant black-oxide finish extends service life in environments exposed to moisture, oils, and industrial chemicals.

Specification Summary & Compliance

This precision set screw features 1/4"-28 UNF fine threads with Class 3A thread fit for exceptional dimensional accuracy and tight tolerance performance. Manufacturing complies with ASME B18.3 specifications and ASTM F912 material standards. The component is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations regarding chemical safety. The 5/16" length and right-hand thread direction provide standardized installation across industrial applications requiring reliable set screw performance.