S-91259A498 8-32 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi shear strength for reliable performance in high-stress assemblies.
• Superior corrosion resistance due to the black oxide finish, extending service life in demanding industrial environments.
• Precision-engineered shoulder with controlled diameter and length tolerances ensures accurate alignment and smooth rotational movement in pivoting applications.
• High-strength alloy steel construction hardened to Rockwell C32 provides excellent durability and wear resistance for long-term use.
• Coarse UNC threading (8-32) allows for faster installation and secure fastening in various materials, reducing assembly time.
• Socket hex drive design enables easy installation with standard tools, offering high torque transmission and a low-profile head.
• Full compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and regulatory adherence for global supply chains.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and rotational needs in precision machinery. The black oxide finish provides a protective layer against rust and corrosion, making it ideal for applications in humid or chemically exposed environments such as automotive assemblies, industrial robots, and conveyor systems. The 8-32 UNC coarse thread and Class 3A thread fit ensure tight, reliable fastening with minimal risk of stripping, while the precisely machined shoulder acts as a pivot point or spacer in linkages, bearings, and gears. By combining high tensile and shear strength with dimensional accuracy, this screw reduces maintenance downtime and enhances the operational lifespan of equipment, delivering consistent performance in heavy-duty industrial applications.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit for precise engagement, with a shoulder diameter of 7/32" (tolerance: -0.004" to -0.002") and shoulder length of 3/8" (tolerance: -0.005" to 0.005"). It conforms to ASME B18.3 specifications and is manufactured from alloy steel under ASTM A574. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety standards for industrial use.