S-90298A622 5/16"-18 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and passivated finish for extended service life in harsh industrial environments.
• Precise component alignment ensured by the 3/8" shoulder diameter with tight tolerance of -0.001" to 0.001" for reliable assembly.
• High-strength performance with 70,000 psi tensile strength and Rockwell B55 hardness to withstand heavy-duty mechanical loads.
• Secure, slip-resistant installation via the knurled socket head with hex drive, allowing for high-torque application without tool slippage.
• Accurate and durable threading with Class 3A fit and coarse UNC thread design for quick assembly and vibration resistance.
• Compliance with industry standards including ASME B18.3, RoHS, and REACH, ensuring safety and regulatory acceptance.
• Versatile right-hand thread compatible with standard UNC nuts and components for broad application across machinery and equipment.

Professional Applications & Engineering Value

This 18-8 stainless steel shoulder screw is engineered to address critical alignment and durability challenges in precision assemblies. The 3/8" shoulder diameter with minimal tolerance provides a stable pivot or bearing surface, reducing wear in rotating parts like gears, pulleys, and linkages. Its 5/16"-18 UNC coarse thread and Class 3A thread fit ensure secure fastening in high-vibration environments, common in automotive, aerospace, and industrial machinery. The passivated finish enhances corrosion resistance, making it ideal for applications exposed to moisture or chemicals. Combined with a knurled socket head for easy hex drive installation, this screw delivers reliable performance in jigs, fixtures, and conveyor systems, where dimensional stability and strength are paramount.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 specifications, with precise dimensions including a 3/8" shoulder diameter (tolerance: -0.001" to 0.001") and 1/2" thread length. The UNC thread follows Class 3A fit standards for superior accuracy, and the material meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring environmental safety and regulatory acceptance in global markets.