S-91264A635 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant secure fastening with integrated nylon pellet thread locker that maintains integrity across a wide temperature range from -50° to 250°F
• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi shear strength for demanding industrial applications
• Precision alignment and smooth rotation thanks to the 1/2" shoulder diameter with tight tolerance control for consistent component positioning
• Superior corrosion resistance through black oxide finish that protects against rust and extends service life in harsh environments
• Reliable thread engagement with Class 3A UNC coarse threads ensuring precise fit and reduced risk of cross-threading during assembly
• Enhanced grip and tool compatibility featuring knurled socket head with 1/4" hex drive for secure tool engagement and reduced slipping
• Industry-standard compliance meeting ASME B18.3 specifications for consistent quality and performance across applications

Professional Applications & Engineering Value

This alloy steel shoulder screw delivers critical engineering solutions for precision machinery and industrial equipment where alignment and rotational movement are paramount. The 2 1/4" shoulder length provides stable bearing surfaces for gears, pulleys, and linkages, eliminating the need for additional spacers while maintaining exact component positioning. The black oxide finish offers superior corrosion protection in manufacturing environments where exposure to moisture and chemicals is common. With its Class 3A UNC coarse threads and integrated nylon pellet thread locker, this fastener prevents loosening under vibration in automotive assemblies, conveyor systems, and robotic equipment. The knurled socket head with hex drive ensures secure tool engagement during installation in confined spaces, reducing assembly time while maintaining torque integrity for high-stress applications.

Specification Summary & Compliance

This shoulder screw features precision Class 3A thread fit with 3/8"-16 UNC coarse threads and maintains tight shoulder diameter tolerance of -0.004" to -0.002" for consistent performance. Manufactured to ASME B18.3 specifications using ASTM A574 alloy steel, it meets rigorous industry standards for dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental responsibility and workplace safety. With Rockwell C32 hardness and verified mechanical properties, this fastener delivers reliable performance in demanding industrial applications where quality and compliance are essential.