S-97345A225 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 chemical exposure.
• Exceptional mechanical strength offering 70,000 psi tensile and 35,000 psi shear strength for reliable, heavy-duty load-bearing applications.
• Precise alignment and spacing provided by the 7/8" shoulder with controlled tolerances, reducing wear and simplifying assembly.
• Secure, high-torque installation enabled by the hex socket drive and knurled head, preventing tool slippage and ensuring consistent fastening.
• Reliable thread engagement with Class 3A fit and coarse 5/16"-18 UNC thread, ensuring vibration resistance and easy assembly in high-stress conditions.
• Long-term durability backed by Rockwell B79 hardness, maintaining structural integrity under repeated use and mechanical stress.
• Full regulatory compliance with ASME B18.3, RoHS 3, and REACH, guaranteeing safety, environmental responsibility, and interoperability in global markets.

Professional Applications & Engineering Value

This 316 Stainless Steel shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and industrial equipment. The 5/16"-18 UNC coarse thread and Class 3A thread fit provide excellent resistance to loosening under vibration, a common failure point in dynamic assemblies. The 7/8" shoulder length acts as a precise pivot or spacer, maintaining alignment in rotating parts like bearings, gears, and linkages, which reduces eccentric wear and extends component life. The hex socket drive and knurled head texture ensure secure tool engagement in confined spaces, speeding up installation while minimizing the risk of damage to the fastener head. Combined with the inherent corrosion resistance of 316 stainless steel, this shoulder screw delivers reliable performance in demanding applications such as food processing, marine hardware, and chemical plant equipment, where moisture, temperature fluctuations, and corrosive agents are prevalent.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC coarse thread with a Class 3A thread fit for high precision and strength. The shoulder diameter is 3/8" with a tolerance of -0.004" to -0.002", and the shoulder length is 7/8" with a tolerance of -0.005" to 0.005", ensuring consistent dimensional accuracy. It is manufactured in compliance with ASME B18.3 specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, confirming its suitability for use in regulated and international industrial markets.