S-90086A639 1/4"-20 x 4" ASME B18.6.3, SAE J933 Tapping Screws

Key Features & Benefits at a Glance

• Superior thread cutting performance with Type F design for reliable, self-tapping installation in tough materials like aluminum, brass, cast iron, and sheet metal without pre-tapping.
• Enhanced corrosion resistance from zinc-plated steel construction, ensuring long-term durability in industrial environments and reducing replacement frequency.
• Optimized drive efficiency with Phillips No. 3 drive style, providing secure tool engagement and reducing cam-out risks during high-torque applications.
• Full-length threading for maximum grip and load distribution along the entire 4" length, ideal for thick-section assemblies and vibration resistance.
• Precise countersinking with an 82° flat head profile, allowing flush mounting to improve aesthetics and prevent snagging in finished products.
• Coarse UNC thread spacing enabling faster installation and higher pull-out strength in soft metals and sheet materials, speeding up production cycles.
• Compliance with industry standards including ASME B18.6.3 and RoHS 3, ensuring consistent quality, safety, and environmental responsibility for B2B procurement.

Professional Applications & Engineering Value

These 1/4"-20 zinc-plated steel tapping screws are engineered to address common industrial fastening challenges, such as material fatigue and installation inefficiency. The Type F thread cutting design and UNC coarse threads allow the screws to form precise, secure threads in aluminum, brass, cast iron, and sheet metal without requiring pre-drilled threads, reducing labor time and tooling costs. The zinc-plated finish provides a protective barrier against rust and corrosion, extending service life in harsh conditions. With a flat head and 82° countersink angle, these screws sit flush to prevent interference in assemblies, while the Phillips drive ensures consistent torque application. Ideal for machinery, automotive, and metal fabrication, they deliver reliable performance where vibration resistance and high-strength connections are critical.

Specification Summary & Compliance

This product adheres to ASME B18.6.3 specifications (referencing SAE J933) for dimensional accuracy and performance, with UNC coarse thread spacing and standard tolerances. The screws are fully threaded with a blunt tip and round shank cross-section, measuring 4" in length and 1/4"-20 in thread size. They are RoHS 3 (2015/863/EU) Compliant, ensuring they meet environmental regulations for hazardous substance restrictions, and are designed for use with a No. 1 drill bit (0.228" diameter) for optimal thread cutting in specified materials.