S-90318A610 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with 316 stainless steel construction, ideal for harsh industrial environments and chemical exposure.
• Precise alignment and pivot functionality ensured by the 1/2" shoulder with a tight diameter tolerance for reliable assembly in mechanical linkages.
• High-strength performance delivering 70,000 psi tensile strength and 35,000 psi shear strength to withstand significant operational loads.
• Optimized for confined spaces with an ultra-low socket head and 5/64" hex drive, allowing for easy installation in compact designs.
• Consistent and reliable threading with Class 2A UNC coarse threads for quick assembly and reduced risk of cross-threading.
• Enhanced durability and wear resistance from a Rockwell B70 hardness, extending the screw's service life in high-cycle applications.
• Compliance with global environmental standards including RoHS 3 and REACH, ensuring safe use in regulated industries.

Professional Applications & Engineering Value

This 4-40 UNC shoulder screw is engineered to address critical alignment and pivot challenges in precision assemblies. The 316 stainless steel material offers superior resistance to corrosion and oxidation, making it suitable for demanding environments like marine, chemical processing, and food machinery. The 1/2" shoulder length provides a stable bearing surface for rotating components, reducing wear and maintaining precise tolerances in linkages, gears, and cam followers. With its ultra-low socket head and hex drive, it facilitates easy installation in tight spaces, while the Class 2A thread fit ensures smooth engagement and reliable fastening. This screw is ideal for applications requiring high strength and durability, such as in automation systems, medical devices, and optical equipment, where consistent performance is paramount.

Specification Summary & Compliance

This shoulder screw adheres to UNC coarse thread standards with a Class 2A thread fit for consistent dimensional accuracy. The shoulder features precise tolerances, including a diameter of 1/8" (-0.001" to 0") and length of 1/2" (0" to 0.002"), ensuring reliable performance in precision assemblies. It complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally conscious and regulated industries.