S-8077A478 4-40 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 Stainless Steel construction, ideal for harsh environments and extending service life.
• Exceptional mechanical strength offering 70,000 psi tensile and 35,000 psi shear strength for reliable performance under high stress.
• Precise alignment and smooth rotation ensured by the Class 3A thread fit and standard shoulder fit, reducing wear and assembly time.
• Enhanced durability and wear resistance from the Black Oxide finish and Rockwell B79 hardness, protecting against galling and surface damage.
• Secure, non-slip fastening facilitated by the knurled socket head and hex drive, allowing for high torque application without stripping.
• Broad compatibility and easy installation with 4-40 UNC coarse right-hand threads, conforming to common industrial standards.
• Compliance with stringent environmental regulations including RoHS 3 and REACH, ensuring safety and suitability for global markets.

Professional Applications & Engineering Value

This 316 Stainless Steel shoulder screw is engineered to address critical challenges in precision assemblies, such as in machinery, automotive, and electronics. The Black Oxide finish not only enhances corrosion resistance but also reduces friction, which is vital for moving parts. Its 2-1/4" shoulder length provides a stable pivot or spacer, minimizing misalignment and vibration in applications like linkages and bearings. The Class 3A thread fit and coarse UNC threading ensure quick, secure fastening, reducing the risk of cross-threading in high-volume production. By combining high tensile and shear strength with a knurled socket head for easy grip, this screw delivers reliable performance in demanding environments, from marine to chemical processing, where durability and precision are paramount.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional tolerances, including a Class 3A thread fit for tight clearances and a shoulder diameter tolerance of -0.004" to -0.002". It conforms to UNC thread standards with a 4-40 coarse thread and right-hand direction. The product is manufactured to meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring it is free from hazardous substances and suitable for industrial use where environmental and safety regulations are critical.