S-90298A604 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 for extended service life in harsh environments
• Precise component alignment ensured by the 4" shoulder with tight diameter tolerance (-0.001" to 0.001") for reliable assembly fit
• High-strength performance with Rockwell B55 hardness and Class 3A thread fit for secure fastening in demanding applications
• Easy installation and removal using the hex socket drive and knurled head for improved grip and torque application
• Industry-standard compatibility with 1/4"-20 UNC coarse threads and compliance with ASME B18.3 specifications
• Environmental regulation compliance meeting RoHS 3 and REACH standards for safe use in regulated industries
• Reliable rotational stability provided by the standard shoulder fit and right-hand thread direction

Professional Applications & Engineering Value

This precision shoulder screw delivers exceptional engineering value in applications requiring exact component positioning and rotational support. The 4" shoulder length with minimal tolerance variations acts as a precise axle or pivot point in machinery assemblies, eliminating the need for additional bushings or spacers. Manufactured from 18-8 stainless steel with a passivated finish, it resists corrosion in industrial environments while maintaining structural integrity. The hex socket drive combined with the knurled head provides secure tool engagement during installation, preventing cam-out in high-torque applications. These features make it ideal for precision equipment, automation systems, and rotating assemblies where Class 3A thread fit ensures vibration resistance and long-term reliability.

Specification Summary & Compliance

This shoulder screw features 1/4"-20 UNC coarse threads with Class 3A thread fit for precision engagement, a shoulder diameter of 5/16" with tolerance of -0.001" to 0.001", and shoulder length of 4" with tolerance of -0.005" to 0.005". The product complies with ASME B18.3 manufacturing specifications and meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards for hazardous substance restrictions.