S-91264A547 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Strength and Durability: With 140,000 psi tensile strength and 84,000 psi shear strength, this screw withstands high-stress applications without failure, ensuring long-term reliability in demanding environments.
• Secure Vibration-Resistant Locking: Integrated nylon pellet provides reliable thread locking from -50° to 250° F, preventing loosening under vibration and thermal cycling for enhanced operational safety.
• Precision Fit and Alignment: Class 3A thread fit and controlled shoulder diameter tolerances ensure accurate assembly and smooth rotation in machinery, reducing wear and maintenance needs.
• Corrosion-Resistant Black Oxide Finish: Offers improved protection against rust and oxidation, extending service life in industrial settings while maintaining a professional appearance.
• Easy Installation and Grip: Hex socket drive (5/32") and knurled head design allow for secure tool engagement and manual handling, speeding up assembly and reducing slippage risks.
• Broad Industrial Compliance: Meets ASME B18.3, RoHS 3, and REACH standards, ensuring compatibility with global regulatory requirements for manufacturing and engineering projects.
• Versatile Shoulder Design: The 1 1/2" shoulder length with standard fit provides stable bearing surfaces for pivoting parts, simplifying precise component alignment in assemblies.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in industrial machinery, automation, and precision equipment. The 1/4"-20 UNC coarse thread with Class 3A fit ensures quick, secure fastening, while the black oxide finish enhances corrosion resistance in humid or abrasive environments. The integrated nylon locking pellet effectively counters vibration-induced loosening, a common issue in dynamic systems like robotics or conveyor belts. With a 1 1/2" shoulder length and precise diameter tolerances, it facilitates accurate alignment of moving parts—such as gears or linkages—reducing friction and wear. Ideal for high-tensile applications in manufacturing, this screw’s Rockwell C32 hardness and compliance with ASME B18.3 make it a dependable choice for engineers seeking durability and regulatory adherence in assembly designs.

Specification Summary & Compliance

This shoulder screw adheres to Class 3A thread fit and UNC coarse thread standards, with shoulder diameter tolerance of -0.004" to -0.002" and length tolerance of -0.005" to 0.005" for precision. Manufactured in compliance with ASME B18.3 and material specification ASTM A574, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in industrial and electronic applications globally.