S-91259A404 4-40 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior strength and durability with alloy steel construction and Rockwell C32 hardness, ensuring reliable performance in demanding applications.
• Enhanced corrosion resistance from the Black Oxide finish, extending service life in various industrial environments.
• Precise alignment and smooth rotation due to the 1/8" shoulder diameter with tight tolerances, reducing wear on mating components.
• High load-bearing capacity with 140,000 psi tensile strength and 84,000 psi minimum shear strength, suitable for high-stress assemblies.
• Secure and reliable fastening achieved through Class 3A thread fit and coarse UNC threading, minimizing loosening under vibration.
• Easy installation and removal with a 5/64" hex socket drive, allowing for efficient assembly in confined spaces.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety and environmental responsibility.

Professional Applications & Engineering Value

This 4-40 UNC Thread Shoulder Screw is engineered to address critical challenges in precision machinery and industrial equipment. The alloy steel material, combined with a Black Oxide finish, provides excellent resistance to corrosion and wear, making it ideal for applications in automotive, aerospace, and manufacturing sectors where exposure to harsh conditions is common. The 1/8" shoulder diameter and 1" shoulder length ensure accurate positioning and smooth pivoting in assemblies, reducing friction and component failure. With a Class 3A thread fit and coarse thread spacing, it offers reliable fastening in high-vibration environments, while the socket head design with a hex drive simplifies maintenance. This shoulder screw delivers consistent performance, enhancing the longevity and efficiency of your engineering projects.

Specification Summary & Compliance

This shoulder screw features precise dimensional tolerances, including a shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005", ensuring high accuracy for Class 3A thread fit and UNC thread standards. It complies with ASME B18.3 specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its adherence to safety and environmental guidelines for industrial use.