S-97345A683 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh environments and extended service life
• Precise component alignment and location ensured by the 3 1/4" shoulder with controlled diameter and length tolerances
• High-strength performance with 70,000 psi tensile and 35,000 psi shear strength for demanding mechanical applications
• Secure, close-tolerance assembly provided by the Class 3A thread fit, minimizing backlash and improving joint integrity
• Easy installation and removal with a hex socket drive and knurled head for enhanced grip and torque application
• Guaranteed reliability and interchangeability through compliance with the rigorous ASME B18.3 standard
• Safe for regulated industries as it is RoHS 3 and REACH compliant, meeting global environmental and safety standards

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to solve critical alignment and pivot point challenges in precision machinery. The 316 stainless steel material offers exceptional resistance to corrosion from chemicals and saltwater, making it a robust choice for marine, chemical processing, and food-grade equipment. The long, 3 1/4" shoulder acts as a precise datum for locating gears, bearings, and linkages, eliminating the need for additional spacers and reducing assembly complexity. The Class 3A thread fit and knurled socket head ensure that the screw remains securely fastened in high-vibration environments, preventing loosening and maintaining operational accuracy. This combination of a durable shoulder diameter and high tensile strength delivers reliable performance in automated systems, conveyor assemblies, and other demanding industrial fastening applications.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC coarse thread with a Class 3A fit for high-precision assemblies. The shoulder diameter is 3/8" with a tolerance of -0.004" to -0.002", and the shoulder length is 3 1/4" with a tolerance of -0.005" to 0.005". It is manufactured to meet the dimensional and mechanical specifications of ASME B18.3. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances for use in global markets.