S-93878A107 4-40 x 5/16" Tapping Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding industrial environments.
• Efficient thread forming design creates strong, permanent threads in materials like steel and aluminum without pre-tapped holes, reducing assembly steps.
• Wide material compatibility for reliable fastening in steel, aluminum, brass, cast iron, and sheet metal, offering versatile application use.
• Optimized drive engagement with Phillips No. 1 drive and pan head design ensures secure torque transmission and reduces cam-out risks.
• Coarse UNC threading provides rapid installation and high pull-out resistance, ideal for high-vibration applications.
• Full thread coverage along the 5/16" length maximizes grip strength and distributes load evenly across the fastened joint.
• Regulatory compliance assurance meets RoHS 3 and REACH standards, ensuring safety and environmental responsibility in global supply chains.

Professional Applications & Engineering Value

These 4-40 UNC thread forming screws are engineered to address common assembly challenges in metalworking and fabrication. The zinc-plated steel material provides a durable barrier against oxidation, crucial for outdoor equipment or humid environments. The thread forming (SW type) design displaces material to create precise, strong threads without generating chips, making them perfect for steel, aluminum, and cast iron components where debris contamination is a concern. The Phillips pan head offers a low-profile, flush finish while the coarse UNC thread spacing ensures quick installation in high-volume production lines. This combination reduces the need for additional tapping operations, lowers labor costs, and enhances joint integrity in sheet metal assemblies, machinery frames, and automotive sub-assemblies.

Specification Summary & Compliance

This product adheres to Unified Coarse (UNC) thread standards with a size of 4-40 and a thread diameter of 0.112". It features a Class 2A tolerance for general purpose use, ensuring consistent fit. The screw is fully threaded with a blunt tip and requires a 2.6 mm (0.1024") drill bit for proper hole preparation. Manufacturing and material compliance are confirmed with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing the absence of restricted hazardous substances.