S-91259A730 3/8"-16 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Enhanced Durability & Corrosion Resistance – Black oxide finish protects against rust and wear in demanding industrial environments, extending service life.
• Superior Tensile & Shear Strength – With 140,000 psi tensile and 84,000 psi minimum shear strength, this screw handles high-stress applications without failure.
• Precision Shoulder Fit & Alignment – The 1/2" shoulder diameter with tight tolerances ensures accurate component positioning and reduces assembly misalignment.
• High Hardness for Wear Resistance – Rockwell C32 hardness provides excellent resistance to deformation and wear under load.
• Secure Hex Drive Installation – 1/4" hex socket drive with knurled head allows for firm grip and easy torque application, minimizing slippage.
• Reliable Thread Engagement – Class 3A UNC coarse threads offer consistent, secure fastening in high-vibration settings.
• Compliance with Industry Standards – Meets ASME B18.3 specifications and is RoHS 3 & REACH compliant, ensuring safety and regulatory adherence.

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and load-bearing challenges in precision machinery, automation systems, and heavy-duty equipment. The 3/8"-16 UNC thread with coarse spacing ensures rapid assembly and reliable performance in high-vibration environments, while the 1/2" shoulder diameter provides a precise pivot or bearing surface for rotating components. The black oxide finish enhances corrosion resistance, making it suitable for applications exposed to moisture or chemicals. Combined with high tensile and shear strength, this socket head shoulder screw reduces the risk of joint failure, minimizes maintenance downtime, and supports efficient production workflows in industries like automotive, aerospace, and industrial manufacturing.

Specification Summary & Compliance

This shoulder screw features a Class 3A thread fit for precise engagement, with shoulder diameter tolerance of -0.004" to -0.002" and shoulder length tolerance of -0.005" to 0.005" to ensure consistent performance. Manufactured in accordance with ASME B18.3 standards and compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it meets rigorous industrial and environmental requirements for safe, reliable use.