S-90390A554 1/4"-20 x 3" Tapping Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black phosphate coating, extending service life in demanding industrial environments.
• High-torque installation capability provided by the T30 Torx drive, reducing cam-out and tool wear for reliable fastening.
• Excellent material compatibility for creating strong threads in aluminum, brass, cast iron, and sheet metal without pre-tapped holes.
• Optimized thread design with UNC coarse 1/4"-20 threads and Thread Cutting (Type F) tapping method for rapid, secure installation.
• Flush mounting and professional finish enabled by the standard flat head with an 82° countersink angle.
• Full-length threading ensures consistent grip and holding power along the entire 3" length of the screw.
• Simplified sourcing and installation with standardized blunt tip design and compatibility with a #1 drill bit (0.228" diameter).

Professional Applications & Engineering Value

These 1/4-20 UNC tapping screws are engineered to solve critical fastening challenges in metalworking and fabrication. The black phosphate steel construction provides a durable, corrosion-resistant base, ideal for applications in aluminum assemblies, brass fittings, cast iron components, and sheet metal enclosures. The thread cutting (Type F) design and coarse UNC threads allow these screws to form precise, strong internal threads in ductile metals, eliminating the need for separate tapping operations and reducing assembly time and cost. The T30 Torx drive offers superior torque transmission compared to traditional drives, minimizing slippage and damage to the screw head during high-stress installations. This combination of material strength, intelligent thread form, and reliable drive style ensures a secure, long-lasting fastening solution that withstands vibration and load in industrial settings.

Specification Summary & Compliance

This product adheres to UNC thread standards with a 1/4"-20 coarse thread and right-hand thread direction. The screw features a standard flat head profile with an 82° countersink angle and is fully threaded with a blunt tip. Manufactured from steel with a black phosphate surface treatment, it is designed for use with a #1 drill bit (0.228" diameter). These screws conform to typical industrial specifications for thread cutting tapping screws (Type F) and are suitable for a wide range of metal fastening applications, ensuring reliable performance and compatibility with industry practices.