S-91327A151 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Secure Vibration Resistance: Integrated nylon patch locking technology prevents loosening under dynamic loads, maintaining assembly integrity in high-vibration environments.
• Exceptional Corrosion Resistance: Made from 18-8 stainless steel with a passivated finish, offering reliable performance in corrosive or humid industrial settings.
• High Tensile Strength: With a tensile strength of 70,000 psi, this shoulder screw withstands heavy-duty mechanical stresses without failure.
• Precision Thread Fit: Class 3A thread fit ensures tight, accurate engagement for reduced backlash and improved alignment in precision assemblies.
• Wide Temperature Tolerance: Nylon patch remains effective from -50° to 250°F, suitable for applications with thermal cycling.
• Easy Installation & Grip: Knurled socket head with hex drive allows for secure tool engagement and manual handling, speeding up assembly processes.
• Dimensional Accuracy: Tight shoulder diameter and length tolerances ensure consistent fit and reliable performance in machined components.

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to address common industrial challenges such as component misalignment, vibration-induced loosening, and corrosion in demanding environments. The 18-8 stainless steel construction and passivated finish provide superior resistance to rust and chemicals, making it ideal for machinery, automotive, and electronics applications where durability is critical. The nylon patch locking feature secures the screw in place, reducing maintenance needs and downtime in high-stress assemblies. With a Class 3A thread fit and precise shoulder dimensions, it ensures accurate positioning and load distribution, enhancing the longevity and reliability of industrial equipment. This screw is commonly used in pivoting mechanisms, bearing mounts, and precision fixtures, offering a robust solution for engineers seeking high-performance industrial shoulder screws.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit with UNC coarse threading for reliable engagement. It adheres to ASME B18.3 manufacturing standards, ensuring dimensional consistency and performance. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it meets environmental and safety requirements for industrial use. Key specifications include a shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005", providing precision for engineering applications.