S-91259A486 5/16"-18 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional durability with alloy steel construction providing 140,000 psi tensile strength and Rockwell C32 hardness for reliable performance in demanding environments.
• Precise alignment and reduced wear thanks to the knurled socket head and Class 3A thread fit, ensuring secure fastening and minimal component slippage.
• Corrosion resistance from the black oxide finish, extending service life in industrial settings exposed to moisture and chemicals.
• Easy installation and removal with a standard hex drive (3/16") and right-hand UNC coarse thread, speeding up assembly and maintenance tasks.
• Accurate positioning due to the 2 1/8" shoulder length with tight tolerances, ideal for guiding moving parts in machinery.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental responsibility.
• Versatile application fit with a 5/16"-18 UNC thread and coarse spacing, suitable for high-vibration and heavy-load scenarios.

Professional Applications & Engineering Value

This alloy steel shoulder screw with a black oxide finish is engineered to address common industrial challenges like misalignment, corrosion, and mechanical stress. The knurled socket head enhances grip during installation, reducing the risk of tool slippage in tight spaces, while the Class 3A thread fit and UNC coarse thread provide superior holding power in high-vibration environments, such as automotive assemblies or manufacturing equipment. Its robust shoulder design acts as a precise pivot or spacer, minimizing wear on adjacent components and ensuring smooth operation in applications like conveyor systems or robotic arms. By combining high tensile strength with regulatory compliance, this screw offers long-term reliability for industrial shoulder screw uses, from machinery guides to stripper bolts.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for tight tolerances and UNC thread specifications. It meets ASME B18.3 manufacturing guidelines and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances. The shoulder diameter tolerance ranges from -0.004" to -0.002", and shoulder length tolerance is -0.005" to 0.005", guaranteeing consistent performance in engineered applications.