S-90251A576 5/16"-18 x 3/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with permanent nylon patch thread locker that maintains secure fastening in high-stress environments
• Superior corrosion resistance from 18-8 stainless steel construction for extended service life in demanding conditions
• Precise thread engagement with Class 3A thread fit ensuring reliable, tight-tolerance connections
• High-temperature performance with thread locker effective from -50° to 250°F for thermal cycling applications
• Secure installation through hex drive design providing positive torque transmission and reduced stripping risk
• Enhanced material strength with Rockwell B80 hardness offering excellent durability under load
• Wide industrial compatibility with UNC coarse threads and cup tip design for optimal gripping on shafts and components

Professional Applications & Engineering Value

This 5/16"-18 UNC Class 3A set screw delivers critical engineering solutions for industrial applications where vibration resistance and positional security are paramount. The nylon patch locking mechanism provides permanent anti-loosening protection without compromising the 18-8 stainless steel material integrity, making it ideal for machinery, automotive components, and precision equipment subjected to thermal cycling. The headless design with hex drive enables flush mounting in confined spaces while maintaining high torque capability. With coarse thread spacing and cup tip configuration, it ensures maximum holding power on rotating shafts and alignment-critical assemblies, addressing common failure points in manufacturing and maintenance operations.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit for precision dimensional accuracy. Features UNC coarse threads with 5/16"-18 thread size and right-hand direction. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards. The nylon patch thread locker maintains performance across the specified temperature range of -50° to 250°F, while the material meets Rockwell B80 hardness requirements for consistent mechanical properties.