S-90311A173 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking: Permanent nylon patch thread locker prevents loosening under dynamic loads, maintaining assembly integrity in high-stress environments.
• Superior corrosion resistance: Made from 316 stainless steel for excellent performance in harsh, corrosive conditions, extending service life.
• High-strength durability: Withstands up to 70,000 psi tensile strength and 35,000 psi shear strength, ensuring reliable performance in demanding applications.
• Precision fit and alignment: Class 3A UNC thread and standard shoulder fit provide accurate positioning and reduced wear in rotating assemblies.
• Wide temperature tolerance: Nylon patch functions effectively from -50° to 250° F, suitable for varied operational climates.
• Easy installation and removal: Hex socket drive and knurled head allow for secure tool engagement and manual handling efficiency.
• Regulatory compliance assurance: Meets ASME B18.3, RoHS 3, and REACH standards, ensuring safety and environmental adherence for global supply chains.

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to address critical challenges in precision machinery and industrial equipment. The Class 3A UNC coarse thread and 1" shoulder length provide exact alignment for rotating components like bearings, pulleys, and linkages, minimizing misalignment and eccentric wear. The nylon patch thread locker offers permanent resistance to vibration-induced loosening, crucial in automotive, aerospace, and manufacturing assemblies where reliability is non-negotiable. With a 3/8" shoulder diameter and Rockwell B79 hardness, it ensures dimensional stability and wear resistance, while the hex socket drive and knurled head facilitate quick maintenance. Ideal for applications demanding corrosion resistance and high tensile strength, this screw reduces downtime and enhances operational safety in harsh environments.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC thread with Class 3A fit for precise engagement, a shoulder diameter tolerance of -0.004" to -0.002", and shoulder length tolerance of -0.005" to 0.005" to ensure consistent performance. It complies with ASME B18.3 manufacturing specifications, RoHS 3 (2015/863/EU) for hazardous substance restrictions, and REACH (EC 1907/2006) for chemical safety, meeting rigorous industrial and environmental standards.