S-97832A321 1/4"-28 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel construction, ideal for harsh industrial environments and extended service life.
• Exceptional thread reliability due to the Class 3A fit and UNF fine thread, ensuring secure, vibration-resistant fastening in precision assemblies.
• High mechanical strength with a tensile strength of 70,000 psi and a shear strength of 35,000 psi, providing dependable performance under heavy loads.
• Enhanced grip and tool engagement from the knurled socket head and hex drive, allowing for secure installation and reducing the risk of stripping.
• Precise component alignment facilitated by the 5/16" shoulder diameter with tight tolerances, minimizing play in pivoting or rotating mechanisms.
• Broad regulatory compliance including ASME B18.3, RoHS 3, and REACH, ensuring suitability for global markets and sensitive applications.
• Optimized for fine-adjustment applications with the 1/4"-28 UNF right-hand thread, offering precise control in assemblies requiring close tolerances.

Professional Applications & Engineering Value

This 18-8 Stainless Steel shoulder screw is engineered to address critical challenges in industrial assembly, where precision, strength, and corrosion resistance are paramount. The Class 3A thread fit and UNF fine thread provide superior holding power in high-vibration environments, preventing loosening in machinery, automotive components, and precision instruments. The knurled socket head with a hex drive ensures positive tool engagement, reducing installation errors and enhancing operator efficiency. Its 5/16" shoulder diameter acts as a precise pivot or locating dowel, eliminating misalignment in rotating assemblies and linkages. Made from 18-8 Stainless Steel, it resists oxidation and chemical exposure, making it ideal for food processing, marine, and outdoor equipment where durability is essential. This screw delivers reliable performance, reducing maintenance cycles and improving the longevity of your engineered systems.

Specification Summary & Compliance

This shoulder screw features a 1/4"-28 UNF fine thread with a Class 3A thread fit for high precision. The shoulder diameter is 5/16" with a tolerance of -0.004" to -0.002", and the shoulder length is 5/16" with a tolerance of -0.005" to 0.005". It is manufactured to ASME B18.3 specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material reliability.