S-91259A432 5/16"-18 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 applications.
• Precise thread engagement ensured by Class 3A thread fit, reducing the risk of loosening and improving assembly consistency.
• Enhanced corrosion resistance from the black oxide finish, extending service life in demanding industrial environments.
• Secure installation and removal with a hex drive socket head and knurled texture, providing superior grip and torque transmission.
• Accurate shoulder positioning with controlled diameter and length tolerances, enabling precise component alignment.
• High durability from alloy steel construction and Rockwell C32 hardness, resisting wear and deformation under heavy use.
• Broad compatibility with UNC coarse threads and compliance to ASME B18.3, ensuring interchangeability and meeting industry standards.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and heavy-duty equipment. The black oxide finish provides a protective layer against rust and corrosion, making it ideal for environments exposed to moisture or chemicals. With a Class 3A thread fit and coarse UNC thread spacing, it offers rapid assembly and reduced cross-threading risks, saving time in high-volume production. The knurled head and hex drive design ensure secure handling during installation, even in confined spaces. Its robust shoulder diameter and length with tight tolerances facilitate exact alignment in pivoting mechanisms, bearing mounts, and linkage assemblies, minimizing vibration and wear. By meeting ASME B18.3 specifications, this screw delivers consistent performance in applications demanding reliability, such as automotive jigs, conveyor systems, and industrial robots.

Specification Summary & Compliance

This shoulder screw adheres to precise dimensional standards, including a Class 3A thread fit for superior engagement and UNC coarse threads with a size of 5/16"-18. Manufacturing conforms to ASME B18.3 and material specifications under ASTM A574, ensuring high quality and repeatability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and regulatory alignment for global supply chains.