S-90251A537 1/4"-20 x 1/2" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking: Permanent nylon patch thread locker ensures secure fastening in high-vibration environments, maintaining clamp load without loosening.
• Superior corrosion resistance: Made from 18-8 stainless steel for excellent durability in humid, chemical, or outdoor industrial settings.
• High-strength threading: Class 3A UNC coarse threads provide tighter tolerances and increased fatigue resistance compared to standard fits.
• Wide temperature tolerance: Nylon locking patch performs reliably from -50°F to 250°F, suitable for diverse operating conditions.
• Secure, flush installation: Headless hex drive design allows countersunk mounting and prevents tampering while offering high torque capability.
• Enhanced grip with cup tip: Concentrated point contact increases holding power on shafts and collars, reducing component slippage.
• Regulatory compliance: Meets ASME B18.3 dimensional standards and environmental regulations (RoHS 3, REACH) for global supply chain use.

Professional Applications & Engineering Value

This 18-8 stainless steel set screw is engineered to solve critical challenges in machinery assembly, where vibration-induced loosening can lead to equipment failure. The permanent nylon patch thread locker embedded in the UNC coarse threads creates consistent friction, eliminating the need for secondary locking devices. Its headless hex drive and cup tip design provide a flush finish and concentrated clamping force, ideal for securing pulleys, gears, and collars on rotating shafts. With a Class 3A thread fit, it ensures precise engagement in tapped holes, reducing wear in high-cycle applications. Suitable for automotive, conveyor systems, and industrial tooling, this vibration-resistant set screw maintains integrity under dynamic loads, minimizing downtime.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with a Class 3A UNC 1/4"-20 thread and coarse pitch for rapid assembly. The screw features a 1/8" hex drive, 1/2" length, and Rockwell B80 hardness for balanced strength and machinability. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to restricted substance guidelines for industrial components.