S-90298A593 1/4"-20 ASME B18.3 Shoulder Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction and passivated finish, ideal for harsh industrial environments
• Exceptional mechanical strength offering 70,000 psi tensile strength and Rockwell B55 hardness for reliable, long-term performance
• Precision alignment and smooth rotation enabled by the 2-1/2" shoulder with tight ±0.005" length tolerance
• Secure, high-precision threading with Class 3A UNC 1/4"-20 coarse thread for superior fit and vibration resistance
• Easy installation and removal via the hex socket drive and knurled head for improved grip and torque application
• Strict dimensional control with shoulder diameter tolerance of -0.001" to 0.001" ensuring consistent assembly quality
• Compliance with major industry standards including ASME B18.3, RoHS, and REACH for guaranteed safety and regulatory acceptance

Professional Applications & Engineering Value

This stainless steel shoulder screw is engineered to solve critical alignment and durability challenges in precision assemblies. Its 2-1/2" shoulder length with minimal tolerance provides a stable bearing surface for rotating components like gears, linkages, and pivots, reducing wear and maintaining concentricity. The Class 3A thread fit and UNC coarse thread ensure secure fastening in high-vibration environments, common in machinery, automation systems, and conveyor equipment. Made from 18-8 stainless steel with a passivated finish, it resists corrosion from oils, moisture, and chemicals, extending service life in demanding industrial settings. The hex socket drive and knurled head allow for efficient installation in confined spaces, making it a reliable choice for OEMs and maintenance teams seeking precision and durability.

Specification Summary & Compliance

This shoulder screw adheres to ASME B18.3 specifications, with a Class 3A thread fit and UNC 1/4"-20 coarse thread for precise engagement. Dimensional accuracy is maintained with shoulder length tolerance of ±0.005" and diameter tolerance of -0.001" to 0.001". The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), ensuring it meets environmental and safety regulations for industrial use.