S-91259A418 8-32 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Tensile and Shear Strength: With 140,000 psi tensile and 84,000 psi minimum shear strength, this screw provides reliable performance in high-stress applications, reducing the risk of failure.
• Superior Corrosion Resistance: The black oxide finish enhances durability by protecting against rust and wear in harsh industrial environments, extending service life.
• Precision Thread Fit: Class 3A thread fit ensures tight, secure fastening with minimal backlash, ideal for assemblies requiring high accuracy and repeatability.
• High Hardness and Durability: Rockwell C32 hardness offers excellent resistance to deformation and wear, maintaining integrity under heavy loads.
• Easy Installation and Removal: The socket head with hex drive (3/32") allows for straightforward tool engagement, speeding up assembly and maintenance processes.
• Standardized Dimensions: UNC coarse threads and consistent shoulder dimensions (e.g., 1/2" shoulder length) ensure compatibility with common industrial components, simplifying procurement.
• Compliance with Industry Standards: Meets ASME B18.3 and ASTM A574 specifications, guaranteeing quality and reliability for engineering applications.

Professional Applications & Engineering Value

This alloy steel shoulder screw with an 8-32 UNC thread and black oxide finish is engineered to address critical challenges in precision machinery, such as minimizing play in rotating assemblies and providing stable pivots in linkages. The coarse thread design facilitates quick installation and robust holding power, while the smooth shoulder diameter ensures precise alignment in bushings or bearings, reducing wear and maintenance downtime. Ideal for industrial applications like automotive systems, robotics, and conveyor equipment, it combines high tensile strength and corrosion resistance to withstand dynamic loads and corrosive environments, enhancing overall system reliability and longevity.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional tolerances, including a Class 3A thread fit for superior accuracy and shoulder diameter tolerance of -0.004" to -0.002". It conforms to ASME B18.3 and ASTM A574 manufacturing standards, ensuring consistent quality. Additionally, it is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible and safe usage in global markets.