S-91979A309 4-40 x 3/16" Set Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel construction for long-lasting performance in harsh environments
• Maximum holding power through cup point tip design that bites into mating surfaces for secure, permanent fastening
• Precise thread engagement with Class 3A thread fit ensuring tight tolerances and reliable installation in critical applications
• Easy installation and removal with hex drive design providing positive torque transmission and preventing tool slippage
• Enhanced functionality with vented feature allowing for pressure equalization or fluid passage in specialized assemblies
• Space-saving design as a headless set screw that sits flush with or below the surface of components
• Regulatory compliance meeting RoHS 3 and REACH standards for environmentally responsible manufacturing

Professional Applications & Engineering Value

This 4-40 UNC set screw delivers exceptional engineering value in precision assembly applications where space constraints and corrosion resistance are critical factors. The 18-8 stainless steel material provides excellent durability against oxidation and chemical exposure, making it ideal for industrial equipment, electronic enclosures, and machinery subjected to demanding environments. The cup point tip creates permanent seating by digging into the shaft material, preventing rotational slippage in power transmission systems and precision instruments. The hex drive design ensures reliable torque application during installation, while the vented feature accommodates specialized requirements in pneumatic systems or applications requiring pressure relief. As a headless set screw, it maintains clean profiles in collars, pulleys, and knobs where protruding fastener heads would interfere with operation.

Specification Summary & Compliance

This precision fastener features 4-40 UNC coarse threads with Class 3A thread fit for superior dimensional accuracy and engagement. The right-hand thread direction follows standard installation conventions, while the 0.050" hex drive accommodates standard tooling. Manufacturing complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental responsibility and material safety. The combination of precise thread specifications and regulated material composition makes this set screw suitable for demanding industrial applications requiring reliable performance and compliance adherence.