S-91259A475 1/4"-20 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional Durability: Crafted from high-grade alloy steel with Rockwell C32 hardness, ensuring long-lasting performance in demanding industrial environments.
• Superior Corrosion Resistance: Black oxide finish provides enhanced protection against rust and oxidation, extending service life in harsh conditions.
• High Tensile Strength: Withstands up to 140,000 psi, offering reliable fastening for high-stress applications without failure.
• Precision Thread Fit: Class 3A UNC coarse threads ensure secure, vibration-resistant connections with minimal risk of loosening.
• Easy Installation & Removal: Hex socket head with 5/32" drive and knurled texture allows for quick, tool-friendly assembly and disassembly.
• Accurate Shoulder Alignment: 7/16" shoulder length with tight tolerances provides precise component positioning and smooth rotational movement.
• Industry Compliance: Meets ASME B18.3 standards and is RoHS 3 & REACH compliant, ensuring safety and regulatory adherence for global use.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical challenges in precision machinery and heavy-duty assemblies. The black oxide finish combats corrosion in humid or chemically aggressive environments, while the 1/4"-20 UNC coarse thread with Class 3A fit ensures rapid installation and superior resistance to vibrational loosening in dynamic systems. The 7/16" shoulder length provides a stable bearing surface for gears, pulleys, and linkages, reducing wear and maintaining alignment. Ideal for robotics, automotive, and aerospace applications, this socket head shoulder screw delivers reliable performance where exact tolerances and high tensile strength are non-negotiable.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 specifications, with a Class 3A thread fit for precise engagement and a shoulder diameter tolerance of -0.004" to -0.002". The UNC coarse thread (1/4"-20) and 7/16" shoulder length with tight tolerances ensure consistent performance. It is manufactured in compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), guaranteeing environmental safety and regulatory acceptance for industrial use worldwide.