S-90311A181 3/8"-16 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction for reliable performance in harsh environments and extended service life.
• High-strength fastening offering 70,000 psi tensile strength and 35,000 psi shear strength to withstand significant mechanical loads and vibrations.
• Secure vibration-resistant locking provided by the integrated Nylon Patch, maintaining clamp load from -50° to 250°F without loosening.
• Precision alignment and pivot function enabled by the 1/2" diameter shoulder with tight tolerances for accurate component positioning.
• Easy installation and high torque application with the hex socket drive and knurled head for superior grip and tool engagement.
• Reliable thread engagement ensured by the Class 3A UNC coarse thread fit, reducing cross-threading risks and ensuring consistent assembly.
• Broad industrial compliance meeting ASME B18.3 specifications and environmental standards like RoHS 3 and REACH for safe, global usage.

Professional Applications & Engineering Value

This 316 Stainless Steel shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and heavy-duty industrial equipment. The 1/2" shoulder diameter with tight manufacturing tolerances provides an exact locating surface for rotating parts, bushings, or linkages, eliminating misalignment and reducing wear. The integrated Nylon Patch thread locker secures the 3/8"-16 UNC coarse thread against vibration-induced loosening, a common failure point in dynamic assemblies. Combined with the hex socket head and knurled texture for high-torque installation, this screw ensures reliable performance in applications ranging from conveyor systems to robotic arms, where high tensile strength and corrosion resistance are paramount for operational safety and longevity.

Specification Summary & Compliance

This shoulder screw adheres to Class 3A thread fit for precise UNC threading, with a shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005" for consistent dimensional accuracy. Manufactured in compliance with ASME B18.3 specifications, it also meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for global industrial and electronic applications without hazardous substances.