S-90087A891 1/4"-20 x 3 1/2" ASME B18.6.3, SAE J933 Tapping Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in demanding environments
• Excellent thread-cutting performance in aluminum, brass, cast iron, and sheet metal without requiring pre-tapped holes
• Maximum holding power through fully threaded UNC coarse design ensuring secure fastening in various materials
• Enhanced drive efficiency with Phillips No. 3 drive style providing reliable torque transmission and reduced cam-out
• Industry-standard compliance meeting ASME B18.6.3 and SAE J933 specifications for consistent quality and performance
• Optimized installation with standard pan head design offering good bearing surface and professional appearance
• Versatile 3½" length suitable for various material thicknesses in industrial and construction applications

Professional Applications & Engineering Value

These 1/4"-20 zinc-plated steel tapping screws deliver exceptional engineering value through their specialized Type F thread cutting design and UNC coarse threading. The combination of zinc-plated steel material and thread cutting capability eliminates the need for separate tapping operations, significantly reducing assembly time and labor costs in aluminum, brass, cast iron, and sheet metal applications. The Phillips No. 3 drive system ensures efficient installation while minimizing tool slippage, making these fasteners ideal for high-volume production environments. Their fully threaded construction provides consistent clamping force throughout the engagement length, preventing loosening under vibration and thermal cycling common in industrial machinery, HVAC systems, and metal fabrication projects.

Specification Summary & Compliance

These tapping screws feature 1/4"-20 UNC coarse threads with standard Class 2A tolerance, ensuring proper fit and engagement in various materials. The 3½" length and 0.492" head diameter provide optimal fastening capabilities for medium to heavy-duty applications. Manufactured in compliance with ASME B18.6.3 specifications and SAE J933 standards, these fasteners guarantee consistent quality and performance. The zinc-plated surface treatment offers corrosion protection while maintaining electrical conductivity. Recommended drill bit size is No. 2 (0.221" diameter) for proper thread engagement in the specified materials.