S-91979A663 1/4"-20 x 1/2" Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction, ideal for harsh industrial environments
• Exceptional holding power from UNC coarse threading and Class 3A fit for secure, vibration-resistant fastening
• Easy installation and removal with 1/8" hex drive design requiring minimal clearance
• Enhanced grip and alignment through cup point tip that bites into materials without splitting
• Pressure equalization capability via 0.062" vent diameter to prevent hydraulic lock in assemblies
• Headless design for flush mounting in confined spaces and rotating components
• Regulatory compliance assurance meeting RoHS 3 and REACH standards for global industrial use

Professional Applications & Engineering Value

This 1/4"-20 UNC Class 3A hex headless set screw delivers critical engineering solutions for industrial applications requiring precision alignment and permanent component positioning. The 18-8 stainless steel construction provides excellent corrosion resistance in manufacturing, automotive, and marine environments, while the cup point design creates deep indentation for maximum resistance to rotational forces and vibration loosening. The vented feature prevents pressure buildup during installation, eliminating potential damage in precision assemblies. With coarse UNC threading and Class 3A fit, this fastener ensures rapid installation and superior clamping force for shafts, collars, and pulleys where reliability is paramount. The headless configuration makes it ideal for applications requiring flush mounting in machinery and equipment with limited clearance.

Specification Summary & Compliance

This precision set screw features 1/4"-20 UNC coarse threading with Class 3A thread fit for tight tolerances and reliable performance. Manufactured from 18-8 stainless steel with a cup point tip and 1/8" hex drive, the fastener measures 1/2" in length with right-hand thread direction. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and global market acceptance for industrial applications.