S-90128A115 4-40 x 1" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc plating protects against rust and extends service life in harsh environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening over time.
• High hardness (Rockwell C37) offers excellent wear resistance and durability under repetitive loading conditions.
• Partially threaded design allows for controlled clamping force and easier alignment in precision machinery.
• Hex socket drive enables high torque application with standard tools, facilitating quick and secure installations.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and suitability for regulated industries.

Professional Applications & Engineering Value

These 4-40 UNC socket head cap screws are engineered to address critical challenges in industrial settings, such as vibration-induced loosening and corrosion in demanding environments. The zinc-plated alloy steel construction provides a robust barrier against moisture and chemicals, making them ideal for machinery, automotive assemblies, and electronic enclosures. With a coarse thread and Class 3A fit, they ensure rapid installation and maintain clamp load under dynamic stresses. The partially threaded rod design concentrates stress efficiently, reducing the risk of thread stripping in thin materials. These screws are widely used in applications requiring high tensile strength and reliability, from precision instruments to heavy-duty equipment, ensuring long-term performance with minimal maintenance.

Specification Summary & Compliance

This product adheres to Class 3A thread fit for precise dimensional accuracy under the UNC (Unified National Coarse) standard. Manufacturing follows ASTM A574 specifications, ensuring consistent quality and performance. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) confirms the absence of hazardous substances, supporting safe use in global industrial markets.