S-93878A123 4-40 x 3/8" Tapping Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in demanding industrial environments
• Excellent thread forming capability creates permanent, vibration-resistant threads in steel, aluminum, brass, cast iron, and sheet metal without pre-tapping
• Optimized drive performance with No. 1 slotted drive design providing reliable torque transmission and installation control
• Enhanced material displacement through coarse UNC thread spacing ensures secure fastening in various base materials
• Full-length threading delivers maximum thread engagement and superior holding power across the entire fastener length
• Streamlined installation process with precise #37 drill bit compatibility (0.104" diameter) for accurate hole preparation
• Versatile pan head design offers a balance of low profile and adequate bearing surface for diverse application requirements

Professional Applications & Engineering Value

These 4-40 UNC thread forming tapping screws provide exceptional engineering value in metal fabrication and assembly operations. The zinc-plated steel construction ensures reliable performance in corrosive environments, while the thread forming design eliminates the need for separate tapping operations, significantly reducing assembly time and labor costs. The SW tapping screw configuration with coarse thread spacing creates strong, permanent threads in various materials including steel, aluminum, brass, cast iron, and sheet metal. The fully threaded shank and blunt tip facilitate smooth material displacement during installation, preventing material cracking in thin sections. These features make them ideal for high-volume production environments where fastening reliability and installation efficiency are critical to operational success.

Specification Summary & Compliance

These 4-40 UNC tapping screws feature standard Class 2A thread tolerances and comply with relevant industrial fastening standards. The thread forming design follows established engineering specifications for SW type tapping screws, ensuring consistent performance across applications. Manufacturing processes adhere to quality control standards, while the zinc plating surface treatment provides basic corrosion protection suitable for general industrial use. The screws are designed for use with standard #37 drill bits (0.104" diameter) and maintain compliance with industry-accepted installation practices for thread forming fasteners in metal assemblies.