S-90669A103 4-40 x 1/8" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior surface protection with soft brass tip that prevents damage to mating components during installation and adjustment
• Exceptional corrosion resistance from 18-8 stainless steel construction for long-term reliability in harsh environments
• Precise thread engagement with Class 3A fit ensuring tight tolerances and secure fastening in critical applications
• Optimized torque transmission through hex drive design that provides reliable installation with standard 0.050" tools
• Enhanced durability with Rockwell B80 hardness balancing strength with necessary toughness for repeated use
• Regulatory compliance assurance meeting ASME B18.3 specifications and environmental standards including RoHS 3 and REACH
• Versatile coarse threading with UNC 4-40 pattern for quick assembly and disassembly in various industrial settings

Professional Applications & Engineering Value

This 4-40 UNC set screw delivers exceptional engineering value in precision assembly applications where component protection is paramount. The 18-8 stainless steel construction provides excellent corrosion resistance for demanding environments, while the soft brass tip eliminates galling and surface damage to expensive mating components. The hex headless design with 0.050" drive size ensures flush mounting in confined spaces while maintaining reliable torque transmission. With Class 3A thread fit and coarse UNC threading, this fastener offers precise positioning capability for shafts, collars, and pulleys in machinery, automotive, and electronic assemblies. The combination of materials and precision manufacturing solves critical challenges in applications requiring repeated adjustments without compromising component integrity.

Specification Summary & Compliance

This set screw maintains Class 3A thread fit tolerances per UNC standards with 4-40 thread size and coarse thread spacing. Manufacturing complies with ASME B18.3 specifications for dimensional accuracy and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in various industrial applications. Additional specifications include right-hand thread direction, 1/8" length, and brass tip configuration with 0.031" length and 0.063" diameter for consistent performance across production runs.