S-90318A590 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh environments and extended service life
• Exceptional mechanical strength offering 70,000 psi tensile strength and 35,000 psi shear strength for reliable load-bearing performance
• Precise alignment and pivot function enabled by the accurate 1/8" shoulder diameter with tight tolerances for minimal assembly play
• Secure, low-profile installation with the ultra-low socket head and 5/64" hex drive, reducing the risk of stripping in confined spaces
• Optimized for rapid assembly using the 4-40 UNC coarse thread and Class 2A fit, ensuring consistent engagement and reduced cross-threading
• Enhanced durability from Rockwell B70 hardness, resisting wear and deformation under repeated use
• Compliance with global standards including RoHS 3 and REACH, ensuring safety and environmental responsibility for industrial applications

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to address critical alignment and mounting challenges in precision assemblies. The 1/8" shoulder diameter provides an exact locating surface, eliminating misalignment in machinery, pivoting mechanisms, and electronic enclosures. Its UNC coarse thread and Class 2A thread fit facilitate quick, reliable fastening, reducing installation time while maintaining integrity under vibration. The ultra-low socket head design allows for flush mounting in space-constrained applications, and the Rockwell B70 hardness ensures the screw withstands mechanical stress without deforming. Ideal for use in robotics, automotive fixtures, and medical devices, this component delivers long-term reliability even in corrosive or high-load environments.

Specification Summary & Compliance

This shoulder screw adheres to UNC thread standards with a Class 2A thread fit for consistent dimensional accuracy. The shoulder features a precise diameter of 1/8" with a tolerance of -0.001" to 0", and a shoulder length of 5/16" with a 0" to 0.002" tolerance, ensuring exact positioning. It is manufactured to meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, confirming its suitability for regulated industrial and electronic applications.