S-94383A370 5/16"-18 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 140,000 psi tensile strength and 84,000 psi shear strength for reliable performance in high-stress applications
• Superior corrosion resistance thanks to the black oxide finish, extending service life in demanding industrial environments
• Precise alignment and secure positioning with Class 3A thread fit and standard shoulder fit, reducing assembly errors and vibration loosening
• Easy installation and removal with hex socket drive and knurled head texture, providing excellent grip and torque transmission
• Enhanced durability and wear resistance from Rockwell C32 hardness alloy steel, maintaining dimensional stability under repeated use
• Broad industry compliance with ASME B18.3, ASTM A574, RoHS 3, and REACH standards, ensuring quality and environmental safety
• Versatile coarse UNC threading (5/16"-18) for quick assembly and disassembly in various mechanical systems

Professional Applications & Engineering Value

This alloy steel shoulder screw is engineered to address critical alignment and load distribution challenges in precision machinery. The 3/8" shoulder diameter with tight tolerances (-0.004" to -0.002") ensures exact component positioning, eliminating play in rotating assemblies like gears, pulleys, and linkages. The black oxide finish provides reliable corrosion protection, making it ideal for automotive, aerospace, and industrial equipment exposed to oils and moderate moisture. With its right-hand UNC thread and Class 3A fit, it offers secure fastening in high-vibration environments, while the knurled socket head allows for efficient torque application without slippage. This screw delivers consistent performance in jigs, fixtures, and motion control systems where shear strength and shoulder stability are paramount.

Specification Summary & Compliance

This shoulder screw maintains precise dimensional accuracy with Class 3A thread fit and shoulder diameter tolerance of -0.004" to -0.002". It adheres to UNC thread standards (5/16"-18) and is manufactured in compliance with ASME B18.3 and ASTM A574 specifications. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental and safety regulations for industrial components.