S-90390A151 1/4"-20 x 1 1/4" Tapping Screws

Key Features & Benefits at a Glance

• Superior torque transmission with T27 Torx drive design, reducing cam-out and tool slippage for reliable installation in industrial settings.
• Enhanced corrosion resistance through zinc-plated steel construction, ensuring long-term durability in harsh environments.
• Efficient thread cutting capability with Type F tapping design, allowing easy installation in aluminum, brass, cast iron, and sheet metal without pre-tapped holes.
• Secure flush mounting with standard flat head profile and 82° countersink angle, providing a smooth surface finish in assembled components.
• Wide material compatibility with 1/4"-20 UNC coarse threads, delivering strong holding power in various metals and reducing vibration loosening.
• Full-length threading for maximum grip along the entire 1 1/4" length, improving load distribution and joint integrity.
• Regulatory compliance with RoHS 3 standards, ensuring safe, environmentally responsible use in global industrial supply chains.

Professional Applications & Engineering Value

These zinc-plated steel tapping screws with 1/4"-20 UNC coarse threads and T27 Torx drive address critical challenges in metal fabrication and assembly. The thread cutting design (Type F) eliminates the need for separate tapping operations, reducing installation time and labor costs in aluminum, brass, cast iron, and sheet metal applications. The flat head with 82° countersink ensures seamless integration into components, preventing protrusions that could interfere with machinery operation. Engineered for high-torque applications, the Torx drive system minimizes strip-out risks, while the fully threaded shank provides consistent clamping force across the entire joint—ideal for vibration-prone environments in automotive, HVAC, and industrial equipment manufacturing.

Specification Summary & Compliance

These screws feature 1/4"-20 UNC coarse threads with standard Class 2A tolerance for reliable fit, fully threaded 1 1/4" length, and right-hand thread direction. The zinc-plated steel construction meets industrial durability requirements, while the 82° countersink angle and 0.228" drill bit size (No. 1) ensure proper installation alignment. Compliance with RoHS 3 (2015/863/EU) confirms adherence to hazardous substance restrictions, making these screws suitable for regulated industrial and export markets.