S-90272A326 4-40 x 2 1/4" ASME B18.6.3 Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with zinc-plated steel construction, extending service life in demanding industrial environments.
• High tensile strength of 60,000 psi ensures reliable, secure fastening under significant mechanical stress.
• Rockwell B70 hardness provides superior durability and resistance to wear and deformation.
• Coarse UNC threads with Class 2A fit offer easier, faster assembly and reduced risk of cross-threading.
• Fully threaded design maximizes grip and load distribution along the entire 2-1/4" length.
• Phillips drive (No. 1 size) allows for efficient installation with common tools, improving workflow productivity.
• Rounded pan head profile provides a low-profile, finished appearance while accommodating standard countersinks.

Professional Applications & Engineering Value

These 4-40 UNC zinc-plated steel rounded head screws are engineered to address critical industrial fastening challenges, such as vibration loosening and environmental corrosion. The coarse thread design ensures rapid installation in a variety of materials, reducing assembly time without compromising holding power. The zinc plating acts as a sacrificial layer, protecting the underlying steel from rust and degradation in humid or outdoor settings. Combined with a fully threaded shank and Phillips drive, these screws deliver consistent clamping force and are ideal for machinery, electrical enclosures, and automotive assemblies where high-strength and regulatory compliance are mandatory.

Specification Summary & Compliance

This product adheres to ASME B18.6.3 specifications for dimensional accuracy and performance. Threads are manufactured to UNC coarse profile with a Class 2A fit for consistent engagement. The screws are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring they are free from hazardous substances and safe for use in regulated industries.