S-91385A353 1/4"-28 x 3/8" ASME B18.3, ASTM F912 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with nylon patch thread locker that maintains secure fastening from -50°F to 250°F
• Precise thread engagement through Class 3A thread fit ensuring superior clamping force and reduced loosening
• Enhanced durability from Rockwell C45 hardened black-oxide alloy steel construction
• Space-saving installation with headless hex drive design for confined applications
• Superior grip and alignment with cup tip design that minimizes surface damage
• Industry-standard compatibility meeting ASME B18.3 specifications for reliable performance
• Environmental compliance with RoHS 3 and REACH regulations for global manufacturing

Professional Applications & Engineering Value

This black-oxide alloy steel set screw with nylon patch thread locker addresses critical vibration-induced loosening in industrial machinery, automotive assemblies, and precision equipment. The Class 3A thread fit and UNF fine threading provide exceptional clamping force while the headless hex drive design allows installation in space-constrained applications. The cup tip configuration minimizes surface marring while maintaining positive engagement, making it ideal for permanent positioning of gears, pulleys, and collars on shafts. With temperature stability from -50°F to 250°F, this set screw delivers reliable performance in demanding environments where thermal cycling and mechanical stress are concerns.

Specification Summary & Compliance

Manufactured to ASME B18.3 standards with Class 3A thread fit precision and UNF 1/4"-28 fine thread specifications. The black-oxide alloy steel construction achieves Rockwell C45 hardness for optimal strength. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in global industrial applications.