S-8077A671 1/4"-28 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh industrial and marine environments.
• Enhanced durability and wear resistance from the black oxide finish, which also provides a sleek, non-reflective surface.
• Precise alignment and secure pivoting ensured by the 2 1/2" shoulder with tight diameter tolerance for reliable performance in assemblies.
• High-strength performance with a tensile strength of 70,000 psi and a minimum shear strength of 35,000 psi for demanding applications.
• Secure, slip-resistant installation thanks to the knurled socket head and 3/16" hex drive, allowing for high torque application.
• Exceptional thread reliability with a fine-pitch 1/4"-28 UNF thread and Class 3A fit, minimizing the risk of loosening under vibration.
• Compliance with major industry standards including ASME B18.3, RoHS 3, and REACH, ensuring material safety and quality.

Professional Applications & Engineering Value

This 316 stainless steel shoulder screw is engineered to solve critical challenges in precision machinery, automation systems, and tooling jigs. The black oxide finish not only enhances corrosion resistance but also reduces galling, a common issue in stainless steel fasteners during high-torque assembly. The long, 2 1/2" shoulder provides an exact unthreaded bearing surface, crucial for maintaining alignment in rotating parts like gears, pulleys, and linkages, which minimizes wear and extends component life. Combined with the Class 3A thread fit and fine UNF thread spacing, it delivers vibration resistance and secure fastening in high-stress environments, making it an indispensable industrial fastener for applications requiring repeatable precision and long-term reliability.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit for high precision, manufactured to ASME B18.3 specifications. The shoulder diameter tolerance is -0.004" to -0.002", and the shoulder length tolerance is -0.005" to 0.005", ensuring dimensional accuracy. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in various industrial and consumer products.