S-90298A643 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh industrial environments.
• Precise alignment and secure positioning thanks to the 5" shoulder length with tight ±0.005" length tolerance.
• High-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness for demanding applications.
• Reliable thread engagement with Class 3A UNC coarse threads ensuring consistent, vibration-resistant fastening.
• Easy installation and removal using the 3/16" hex drive and knurled head for improved grip and torque application.
• Exceptional dimensional stability with shoulder diameter tolerance of ±0.001" for exact fit in assemblies.
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH for safe, regulated use.

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to solve critical alignment and durability challenges in industrial machinery, automation systems, and precision equipment. The 18-8 stainless steel material, combined with a passivated finish, provides excellent resistance to rust and chemical exposure, extending service life in demanding conditions. The 5" shoulder length with minimal tolerance ensures accurate component spacing and rotational stability, reducing wear and misalignment in pivoting mechanisms or bearing mounts. The Class 3A thread fit and coarse UNC thread design offer robust, vibration-resistant connections, making it ideal for high-stress assemblies where reliability is paramount. Its 3/16" hex drive and knurled head facilitate quick, secure installation in confined spaces, enhancing maintenance efficiency.

Specification Summary & Compliance

This shoulder screw adheres to Class 3A thread fit for precise, high-quality engagement, manufactured in accordance with ASME B18.3 specifications. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance standards, ensuring environmental safety and regulatory acceptance. The shoulder features a diameter tolerance of -0.001" to 0.001" and length tolerance of -0.005" to 0.005", guaranteeing consistent performance in precision applications.