S-91327A137 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with integrated nylon patch that maintains secure fastening from -50° to 250°F, preventing loosening in dynamic applications
• Exceptional corrosion resistance through 18-8 stainless steel construction with passivated finish, ensuring longevity in harsh industrial environments
• Precision alignment capability with Class 3A thread fit and standardized shoulder diameter, providing accurate component positioning
• High-strength performance delivering 70,000 psi tensile strength and Rockwell B55 hardness for reliable load-bearing capacity
• Easy installation and removal with hex socket drive and knurled head texture for superior tool grip and torque application
• Industry-standard compatibility meeting ASME B18.3 specifications with UNC coarse threads for broad application suitability
• Environmental compliance assurance with RoHS 3 and REACH compliance for global regulatory acceptance

Professional Applications & Engineering Value

This 1/4"-20 UNC shoulder screw delivers critical engineering solutions for precision assembly challenges. The 18-8 stainless steel construction with passivated finish provides superior corrosion resistance in manufacturing environments exposed to moisture and chemicals. The integrated nylon patch thread locker effectively counters vibration-induced loosening in machinery, automotive, and aerospace applications where thermal cycling from -50° to 250°F occurs. The Class 3A thread fit ensures precise engagement with mating components, while the standardized shoulder diameter facilitates accurate alignment in rotating assemblies and bearing mounts. The hex socket drive with knurled head enables high-torque installation without slippage, making it ideal for confined spaces in industrial equipment maintenance and precision instrument manufacturing.

Specification Summary & Compliance

This shoulder screw maintains Class 3A thread fit with UNC coarse threading (1/4"-20) and complies with ASME B18.3 manufacturing standards. The shoulder diameter tolerance is maintained between -0.004" to -0.002" with shoulder length tolerance of -0.005" to 0.005" for precision applications. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial markets.