S-90298A608 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and passivated finish, ideal for harsh industrial environments
• Precise component alignment ensured by the 4-1/2" shoulder length with tight ±0.005" tolerance for reliable assembly
• High-strength durability from Rockwell B55 hardness, maintaining structural integrity under mechanical stress
• Secure and efficient installation with hex socket drive and knurled head, preventing slippage during torque application
• Reliable thread engagement thanks to Class 3A UNC coarse threads, reducing cross-threading risks in high-vibration applications
• Industry-standard compliance with ASME B18.3, RoHS 3, and REACH, ensuring safety and regulatory adherence
• Consistent dimensional accuracy with a shoulder diameter tolerance of -0.001" to 0.001" for uniform performance

Professional Applications & Engineering Value

This shoulder screw is engineered to address critical alignment and wear challenges in industrial applications such as machinery pivots, rotating assemblies, and precision guides. The 18-8 stainless steel construction, combined with a passivated finish, provides exceptional resistance to corrosion and chemical exposure, extending service life in demanding conditions. The 4-1/2" shoulder length with minimal tolerance ensures exact positioning of components, reducing misalignment and premature wear. The UNC coarse thread and Class 3A fit facilitate quick assembly while maintaining high strength, making it ideal for high-vibration environments where loosening is a concern. The hex socket drive and knurled head further enhance installation efficiency, supporting reliable performance in automated systems and heavy-duty equipment.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC coarse thread with Class 3A fit for precise thread engagement, and a shoulder diameter of 3/8" with a tolerance of -0.001" to 0.001". The shoulder length is 4-1/2" with a tolerance of -0.005" to 0.005", ensuring dimensional accuracy. It is manufactured in compliance with ASME B18.3 standards and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, providing assurance for use in regulated industrial and commercial applications.