S-91264A580 5/16"-18 ASME B18.3, ASTM A574 Shoulder Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with integrated nylon pellet thread locker, maintaining secure fastening from -50° to 250° F in demanding environments.
• Exceptional load-bearing capacity thanks to alloy steel construction, delivering 140,000 psi tensile strength and 84,000 psi minimum shear strength for heavy-duty applications.
• Precise alignment and reduced wear with a 3/8" shoulder diameter and tight tolerances, ensuring accurate component positioning and extended service life.
• Reliable thread engagement through Class 3A fit and coarse 5/16"-18 UNC threads, providing easy assembly and high resistance to loosening under stress.
• Enhanced durability and corrosion resistance from the black oxide finish, offering protection in harsh industrial settings while maintaining Rockwell C32 hardness.
• Secure and easy installation with a knurled socket head and 3/16" hex drive, allowing for firm grip and efficient torque application without slippage.
• Compliance with industry standards including ASME B18.3, RoHS 3, and REACH, ensuring safety, environmental responsibility, and consistent quality.

Professional Applications & Engineering Value

This high-strength shoulder screw is engineered to address critical challenges in precision machinery, automotive assemblies, and heavy industrial equipment. The alloy steel core and black oxide finish provide robust resistance to wear and corrosion, while the Class 3A thread fit and coarse UNC threads ensure reliable fastening in high-vibration environments. The integrated nylon pellet locking technology prevents unintended loosening, maintaining joint integrity across a wide temperature range from -50° to 250° F. With a precisely machined shoulder diameter of 3/8" and tight tolerances, it facilitates accurate alignment of moving parts, reducing friction and extending component lifespan in pivots, linkages, and rotating mechanisms. This design minimizes maintenance needs and enhances overall assembly reliability for B2B clients seeking durable, ASME B18.3 compliant fastening solutions.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC thread with Class 3A fit for precise dimensional accuracy, alongside a shoulder diameter of 3/8" (tolerance: -0.004" to -0.002") and shoulder length of 5/8" (tolerance: -0.005" to 0.005"). Manufactured in accordance with ASME B18.3 specifications and ASTM A574 standards, it ensures consistent performance. The product is fully RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliant, meeting environmental and safety regulations for industrial use.