S-90390A555 1/4"-20 x 3 1/2" Tapping Screws

Key Features & Benefits at a Glance

• Superior torque transmission with T30 Torx drive design that prevents cam-out and allows for higher installation torque
• Enhanced corrosion resistance through black-phosphate steel construction for extended service life in demanding environments
• Efficient thread cutting action with Type F design that creates mating threads in materials without requiring pre-tapped holes
• Flush installation capability with 82° countersink angle and flat head profile for smooth, professional finishes
• Versatile material compatibility specifically engineered for aluminum, brass, cast iron, and sheet metal applications
• Reliable fastening performance with fully threaded UNC coarse thread design that ensures maximum holding power
• Optimized installation process with recommended No. 1 drill bit size (0.228") for precise hole preparation

Professional Applications & Engineering Value

These black-phosphate steel tapping screws with T30 Torx drive deliver exceptional engineering value in industrial fastening applications. The thread cutting Type F design eliminates the need for separate tapping operations, significantly reducing assembly time and labor costs in aluminum, brass, cast iron, and sheet metal components. The UNC coarse thread configuration provides superior pull-out resistance in softer materials, while the 82° countersink angle ensures flush mounting for applications requiring smooth surfaces. The combination of fully threaded construction and thread cutting capability creates reliable, vibration-resistant connections that maintain integrity under dynamic loads, making these tapping screws ideal for manufacturing, construction, and metal fabrication industries where durability and installation efficiency are critical.

Specification Summary & Compliance

This 1/4"-20 x 3-1/2" tapping screw features UNC coarse thread specifications with Class 2A tolerance for precise fitment. Manufactured to industry standards for thread cutting Type F tapping screws, it complies with relevant industrial fastening specifications. The product meets RoHS and REACH compliance requirements for environmental safety and contains no restricted substances. The black-phosphate surface treatment provides consistent corrosion protection while maintaining dimensional accuracy across the fully threaded shank and standard flat head profile.