S-90778A111 4-40 x 1/4" ASME B18.3 Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh environments and chemical exposure
• Exceptional thread reliability with Class 3A fit, ensuring precise engagement and reduced risk of cross-threading
• High mechanical strength from Rockwell B80 hardness, providing excellent resistance to wear and deformation
• Secure anti-loosening performance with 90° cone point design that bites into surfaces for vibration-resistant fastening
• Easy installation in confined spaces using the 0.050" hex drive headless design
• Broad industrial compatibility with UNC coarse threads for quick assembly and disassembly
• Regulatory compliance assurance meeting ASME B18.3 standards and environmental regulations (RoHS 3 & REACH)

Professional Applications & Engineering Value

This 4-40 UNC set screw delivers critical engineering solutions where corrosion resistance and vibration resistance are paramount. The 316 stainless steel composition provides exceptional performance in marine, chemical processing, and food equipment applications where moisture and corrosive agents degrade ordinary fasteners. The hex headless design with 0.050" drive enables installation in tight spaces while maintaining flush surfaces. The 90° cone point creates permanent seating in shafts, collars, and pulleys, preventing slippage under dynamic loads. With Class 3A thread fit and coarse thread spacing, these set screws offer reliable engagement in both soft and hard materials, making them ideal for precision machinery, automotive components, and industrial equipment requiring secure positional locking.

Specification Summary & Compliance

This 4-40 UNC set screw features precise Class 3A thread fit with 0.112" thread diameter and 1/4" length. 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, containing no restricted substances. Thread configuration follows UNC coarse thread standards with right-hand direction for universal compatibility across industrial applications.