S-90390A126 5/16"-18 x 4" Tapping Screws

Key Features & Benefits at a Glance

• Superior thread cutting performance in aluminum, brass, cast iron, and sheet metal for reliable, secure fastening without pre-tapped holes.
• Enhanced corrosion resistance with black-phosphate steel coating, extending service life in demanding industrial environments.
• High-torque installation capability via T40 Torx drive, reducing cam-out risk and enabling efficient, secure driving.
• Optimal material displacement with UNC coarse threads and Type F thread cutting design, ensuring strong thread engagement and vibration resistance.
• Flush, professional finish achieved with an 82° countersink angle and standard flat head profile, ideal for applications requiring a smooth surface.
• Full threading along the 4" length provides maximum grip and holding power across the entire fastener engagement area.
• Streamlined installation process using a standard L drill bit (0.29" diameter), reducing preparation time and improving assembly efficiency.

Professional Applications & Engineering Value

These 5/16"-18 thread cutting tapping screws are engineered to solve common industrial fastening challenges in materials like aluminum, brass, cast iron, and sheet metal. The black-phosphate steel construction provides a durable, corrosion-resistant base, while the Type F thread cutting design and UNC coarse threads efficiently form mating threads without pre-tapping, significantly reducing assembly time and labor costs. The T40 Torx drive ensures high torque transfer, minimizing tool slippage and damage to the screw head during installation. This combination of full threading, precise 82° countersink, and robust material makes these screws ideal for heavy-duty applications in machinery, metal fabrication, and construction, where vibration resistance and long-term reliability are critical.

Specification Summary & Compliance

This product adheres to standard UNC thread specifications with coarse thread spacing, ensuring compatibility with common industrial requirements. The screws are manufactured to precise dimensional standards, including a 5/16"-18 thread size, 4" length, and standard flat head profile. They are designed for use with an L drill bit (0.29" diameter) and feature a right-hand thread direction and blunt tip for controlled installation. Compliant with industry-accepted practices for thread cutting tapping screws (Type F), these fasteners are suitable for various regulatory and quality standards in industrial fastener applications.