S-90318A202 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 Stainless Steel construction, ideal for harsh or chemical-exposed environments.
• High-strength performance offering 70,000 psi tensile and 35,000 psi shear strength for reliable load-bearing in demanding applications.
• Precision assembly fit ensured by the Class 2A thread fit and precise shoulder diameter, minimizing play and vibration.
• Space-saving low-profile design with an ultra-low socket head, allowing use in compact assemblies without compromising drive engagement.
• Enhanced durability and longevity from the passivated finish, which increases surface hardness and resistance to wear.
• Broad regulatory compliance meeting RoHS 3 and REACH standards, ensuring safety and environmental responsibility for global markets.
• Secure and efficient installation with a 5/64" hex drive, providing a firm grip and reducing the risk of stripping during torque application.

Professional Applications & Engineering Value

This 4-40 UNC shoulder screw in 316 Stainless Steel is engineered to address critical challenges in precision machinery, automation systems, and electronic enclosures. The ultra-low socket head and precise shoulder fit prevent misalignment and reduce stress concentrations, which is vital for maintaining accuracy in assemblies with rotating parts or tight tolerances. The coarse UNC thread and Class 2A fit ensure quick, secure fastening while the passivated finish enhances corrosion resistance, making it suitable for medical, marine, or food processing equipment where hygiene and durability are paramount. By combining high tensile and shear strength, this screw delivers reliable performance under dynamic loads, minimizing downtime and maintenance costs.

Specification Summary & Compliance

This precision shoulder screw adheres to UNC thread standards with a Class 2A thread fit for consistent engagement. Dimensions include a 0.25" head diameter, 1/4" shoulder length with tight tolerances (e.g., shoulder diameter: -0.001" to 0"), and a 5/32" thread length. It is manufactured to meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring it is free of hazardous substances and suitable for regulated industries.