S-91327A152 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with integrated nylon patch thread locker, maintaining secure fastening from -50° to 250° F to prevent loosening in dynamic applications.
• Exceptional corrosion resistance from 18-8 stainless steel and passivated finish, ideal for harsh environments and extending service life.
• High tensile strength of 70,000 psi with Rockwell B55 hardness, ensuring reliable load-bearing capacity and durability under stress.
• Precision Class 3A thread fit with UNC coarse threads for easy assembly and consistent engagement in industrial machinery.
• Secure hex drive and knurled head providing non-slip grip during installation, reducing tool slippage and improving efficiency.
• Accurate shoulder dimensions with tight tolerances for stable alignment in pivoting or rotating assemblies.
• Compliance with ASME B18.3 and environmental standards (RoHS 3, REACH), ensuring quality and safety for regulated industries.

Professional Applications & Engineering Value

This shoulder screw is engineered to address common industrial challenges such as misalignment, vibration-induced loosening, and corrosion in demanding environments. The 18-8 stainless steel construction, combined with a passivated finish, offers superior resistance to rust and chemicals, making it suitable for machinery, automotive, and outdoor equipment. The nylon patch thread locker provides reliable vibration resistance without requiring additional adhesives, simplifying maintenance in assemblies exposed to temperature fluctuations. With a coarse UNC thread and precise Class 3A fit, it ensures quick installation and secure fastening in high-stress applications, reducing downtime and enhancing operational reliability. Ideal for use in pivoting joints, rotating shafts, and precision instruments, this screw delivers long-term performance where durability and accuracy are critical.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC thread with Class 3A fit for precise tolerance, and a shoulder diameter tolerance of -0.004" to -0.002" with length tolerance of -0.005" to 0.005" to ensure consistent alignment. It is manufactured in compliance with ASME B18.3 specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, confirming its suitability for global industrial use without hazardous substances.