S-91259A153 4-40 ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 140,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure.
• High shear resistance (84,000 psi minimum) provides superior durability in applications involving lateral forces and vibration.
• Black oxide finish offers enhanced corrosion protection, extending service life in harsh industrial environments.
• Rockwell C32 hardness delivers excellent wear resistance, maintaining dimensional stability and thread integrity over time.
• Class 3A thread fit ensures precise, secure fastening with minimal play, ideal for high-precision assemblies.
• 5/64" hex drive socket head allows for easy installation and removal with standard tools, improving assembly efficiency.
• Alloy steel construction combined with ASTM A574 compliance guarantees consistent quality and mechanical properties.

Professional Applications & Engineering Value

This 4-40 UNC thread shoulder screw is engineered to address critical challenges in precision machinery, automation systems, and heavy-duty equipment. The alloy steel material and black oxide finish provide robust resistance to corrosion and wear, making it suitable for environments exposed to moisture, chemicals, and repetitive motion. The shoulder design with precise diameter and length tolerances ensures accurate alignment of components, reducing assembly errors and enhancing operational reliability. Its high tensile and shear strength supports demanding applications such as robotic arms, conveyor systems, and aerospace assemblies, where fastener integrity is paramount. By incorporating Class 3A thread fit and a socket head for secure driving, this screw minimizes loosening under vibration, delivering long-term performance and reducing maintenance needs.

Specification Summary & Compliance

This shoulder screw adheres to UNC coarse thread standards with a Class 3A thread fit for superior precision and tight tolerances. It meets ASTM A574 specifications for alloy steel socket head cap screws, ensuring consistent mechanical properties and manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety and environmental standards for global industrial use.