S-97768A432 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Enhanced Durability: Crafted from 18-8 stainless steel with a black oxide finish for superior corrosion resistance and long service life in harsh industrial environments.
• Precision Alignment & Bearing Surface: Features a 1-1/2" shoulder length with a controlled diameter tolerance to act as a precise pivot, shaft, or bearing surface, reducing wear on assembled components.
• High-Strength Fastening: Delivers a robust 70,000 psi tensile strength and 35,000 psi minimum shear strength, ensuring reliable performance under significant mechanical loads.
• Secure & Repeatable Installation: The knurled socket head with a 1/4" hex drive provides excellent grip and prevents tool slippage, while the Class 3A thread fit on the 5/16"-18 UNC coarse thread ensures consistent, tight engagement.
• Industry Compliance & Reliability: Manufactured to meet ASME B18.3 specifications and is RoHS 3 and REACH compliant, guaranteeing material quality and environmental safety for global supply chains.
• Optimized for Heavy-Duty Use: The combination of Rockwell B55 hardness and a coarse thread design provides excellent resistance to stripping and vibration, ideal for demanding applications.

Professional Applications & Engineering Value

This shoulder screw is engineered to solve critical alignment and pivot-point challenges in machinery and assemblies. The 1-1/2" shoulder length provides a precise, unthreaded bearing surface that supports rotating parts like gears, pulleys, and linkages, minimizing friction and wear. The 18-8 stainless steel construction and black oxide finish offer exceptional resistance to rust and corrosion, making it suitable for use in automotive, packaging, and other industrial equipment exposed to moisture or chemicals. The Class 3A thread fit and coarse UNC thread ensure quick assembly and high resistance to vibrational loosening, while the knurled socket head allows for secure torque application in confined spaces. This design delivers reliable performance, reduces maintenance downtime, and extends the lifecycle of the assembly.

Specification Summary & Compliance

This shoulder screw features a 5/16"-18 UNC coarse thread with a precision Class 3A thread fit for superior engagement. The shoulder diameter is 1/2" with a tolerance of -0.004" to -0.002", and the shoulder length is 1-1/2" with a tolerance of -0.005" to 0.005". It is manufactured in compliance with the ASME B18.3 standard and adheres to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring material safety and performance reliability.