S-91259A637 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 minimum shear strength for reliable performance in demanding applications.
• Superior corrosion resistance provided by the black oxide finish, extending service life in harsh industrial environments.
• Precise alignment and secure mounting ensured by the Class 3A thread fit and standard shoulder fit, reducing assembly errors.
• High durability and wear resistance from alloy steel construction and Rockwell C32 hardness, minimizing deformation under stress.
• Easy installation and removal with a 3/16" hex drive and knurled head texture, offering improved grip and torque application.
• Broad compatibility with UNC coarse threads and right-hand direction, suitable for various machinery and equipment.
• Regulatory compliance meeting ASME B18.3, RoHS 3, and REACH standards for safe and sustainable use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision industrial applications, such as machinery assembly, automotive components, and robotic systems. The black oxide finish enhances corrosion protection, reducing maintenance needs in humid or abrasive conditions. With a 3 1/4" shoulder length and precise Class 3A thread fit, it provides stable axial support and minimizes misalignment, ensuring smooth operation in rotating parts or pivoting mechanisms. The coarse UNC threads and right-hand direction facilitate quick installation, while the high tensile and shear strengths prevent failure under dynamic loads, making it ideal for shoulder mounting solutions that demand reliability and longevity.

Specification Summary & Compliance

This shoulder screw adheres to Class 3A thread fit and UNC coarse thread standards, with a shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005" for consistent precision. It meets ASME B18.3 specifications and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and quality assurance.