S-90311A175 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Secure vibration-resistant locking with the integrated nylon patch that maintains integrity across a wide temperature range from -50° to 250°F, reducing maintenance needs in dynamic environments.
• Superior corrosion resistance thanks to 316 Stainless Steel construction, ideal for harsh or marine applications where moisture and chemicals are present.
• Precise alignment and smooth rotation enabled by the knurled socket head and standard shoulder fit, ensuring accurate component positioning and reduced wear.
• High load-bearing capacity with 70,000 psi tensile strength and 35,000 psi minimum shear strength, providing reliable performance under heavy mechanical stress.
• Consistent thread engagement through Class 3A thread fit and UNC coarse threading, offering easy assembly and reduced risk of cross-threading.
• Durable and long-lasting with Rockwell B79 hardness, ensuring the screw withstands repeated use without deformation.
• Easy installation and removal using a standard hex drive (3/16"), combined with the right-hand thread direction for straightforward fastening in industrial settings.

Professional Applications & Engineering Value

This 5/16"-18 UNC shoulder screw is engineered to address common industrial challenges such as misalignment, vibration loosening, and corrosion in precision assemblies. Made from 316 Stainless Steel, it excels in demanding environments like machinery, automotive, and marine equipment, where exposure to moisture, salts, or chemicals can degrade lesser materials. The nylon patch thread locker ensures secure fastening even under constant vibration, reducing downtime for retightening. With a 1-1/2" shoulder length and 3/8" shoulder diameter, it provides stable support for rotating parts like bearings or pulleys, enhancing overall system reliability. The coarse thread and Class 3A fit facilitate quick assembly while maintaining tight tolerances, making it a go-to solution for B2B applications requiring durability and precision.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 standards, ensuring dimensional accuracy with a Class 3A thread fit and shoulder tolerances (e.g., shoulder diameter: -0.004" to -0.002"). It is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), supporting environmentally responsible sourcing. The specifications include a right-hand UNC thread type and precise shoulder dimensions for reliable performance in industrial fastening systems.