S-93878A311 1/4"-20 x 5/8" Tapping Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction for extended service life in harsh industrial environments.
• Excellent thread-forming capability creates strong, permanent threads in ductile materials without pre-tapping, saving assembly time and labor.
• High-strength fastening in steel, aluminum, brass, and cast iron thanks to the coarse UNC 1/4"-20 thread profile for superior vibration resistance.
• Efficient installation with a standard Phillips No. 3 drive, providing a common and accessible drive option for various tools.
• Optimized material displacement requiring only a 0.234" drill bit (Size A), minimizing stress on the host material for secure, reliable joints.
• Versatile application range from sheet metal to heavier castings, making it a single-solution fastener for diverse metalworking projects.
• Full threading along the 5/8" length ensures maximum grip and consistent clamping force across the entire engagement area.

Professional Applications & Engineering Value

These zinc-plated steel thread forming screws are engineered to solve critical challenges in metal assembly. The SW type thread forming design displaces material to create a zero-clearance fit, eliminating the need for tapped holes and significantly reducing assembly steps. This is particularly valuable in steel, aluminum, brass, and cast iron applications where stripping or weak threads are a common failure point. The coarse UNC thread and blunt tip facilitate easier starting and reduce the risk of cross-threading, ensuring a reliable, high-strength connection that withstands vibration and load cycles in demanding industrial environments. This combination of features delivers reduced installation time, lower total cost of ownership, and enhanced joint integrity.

Specification Summary & Compliance

This fastener features a 1/4"-20 UNC coarse thread with standard Class 2A tolerances, ensuring consistent and interchangeable fit. The thread forming (SW Type) manufacturing conforms to industry standards for tapping screws. The zinc plating provides a protective finish, and the product is compliant with RoHS and REACH environmental directives. Manufactured to meet common industrial specifications for dimensional accuracy and performance.