S-91259A421 8-32 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength: Withstands up to 140,000 psi, providing reliable performance in high-stress applications and reducing the risk of fastener failure.
• Superior Shear Resistance: Minimum shear strength of 84,000 psi ensures secure fastening under lateral loads, enhancing joint integrity.
• Precision Class 3A Thread Fit: Delivers tight, secure connections with minimal backlash, ideal for precision assemblies requiring exact alignment.
• Durable Alloy Steel Construction: Offers high Rockwell C32 hardness for excellent wear resistance and long service life in demanding environments.
• Corrosion-Resistant Black Oxide Finish: Protects against rust and oxidation, extending the screw's lifespan in various industrial conditions.
• Standard Socket Head with Hex Drive: Allows for easy installation and removal using common 3/32" hex tools, streamlining assembly and maintenance.
• Coarse UNC Threads: Facilitate quick assembly and disassembly, improving efficiency in production and repair operations.

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 essential corrosion protection, while the Class 3A thread fit ensures minimal play and vibration resistance in dynamic applications. Its 8-32 UNC coarse thread allows for rapid installation, reducing assembly time without compromising strength. The smooth socket head design with a hex drive enables easy access in confined spaces, making it ideal for industrial fasteners in robotics, automotive, and aerospace sectors where reliability and precision are paramount. The robust shoulder diameter and length tolerances support accurate positioning of components, preventing misalignment and enhancing overall system durability.

Specification Summary & Compliance

This shoulder screw features precise dimensions, including a shoulder diameter of 7/32" with a tolerance of -0.004" to -0.002" and a shoulder length of 1" with a tolerance of -0.005" to 0.005". The thread fit adheres to Class 3A standards for high precision, and the UNC thread type with coarse spacing ensures compatibility with common assemblies. It meets ASME B18.3 and ASTM A574 specifications for quality and performance, and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe and sustainable use.