S-97345A611 1/4"-28 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh environments including marine and chemical processing applications.
• Enhanced precision and load-bearing capability from the 2" shoulder with tight tolerances, ensuring accurate component alignment and reduced wear.
• High-strength performance offering 70,000 psi tensile strength and 35,000 psi minimum shear strength for demanding mechanical assemblies.
• Secure, non-slip installation facilitated by the knurled socket head and 3/16" hex drive, allowing for high torque application without tool slippage.
• Reliable fine-thread engagement with 1/4"-28 UNF Class 3A fit, providing superior vibration resistance and leak-proof sealing in precision equipment.
• Long-term durability backed by Rockwell B79 hardness, maintaining structural integrity under repeated stress and exposure.
• Broad regulatory compliance meeting ASME B18.3, RoHS 3, and REACH standards, ensuring safety and suitability for global industrial markets.

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and fixturing applications. The extended 2" shoulder length with minimal diameter tolerance provides a stable pivot or spacer, eliminating misalignment and reducing bushing wear. The fine UNF threading (1/4"-28) and Class 3A fit ensure tight, secure fastening in high-vibration environments, preventing loosening in industrial equipment. Combined with the knurled socket head for positive grip during installation, this screw delivers reliable performance in assembly lines, robotics, and optical devices where precision and corrosion resistance are paramount.

Specification Summary & Compliance

The screw adheres to Class 3A thread fit and ASME B18.3 specifications, ensuring dimensional accuracy for the 1/4"-28 UNF fine threads and shoulder components. Shoulder diameter tolerance is maintained between -0.004" to -0.002", with shoulder length tolerance of -0.005" to 0.005" for consistent performance. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and material integrity for industrial use.