S-98070A520 4-40 x 3/4" Sealing Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior Sealing Performance: Integrated silicone rubber O-ring creates a reliable seal capable of withstanding pressures up to 6000 psi, preventing leaks in critical applications.
• Exceptional Corrosion Resistance: Constructed from 18-8 Stainless Steel with a passivated finish for enhanced durability and long-term performance in harsh environments.
• Wide Temperature Tolerance: The silicone rubber O-ring maintains its sealing integrity across an extreme temperature range from -80° to 400° F.
• High Mechanical Strength: Offers a robust 70,000 psi tensile strength, ensuring the fastener can handle significant structural loads.
• Precision Thread Fit: Features a Class 2A thread fit and UNC coarse threads for easy installation and a secure, reliable hold.
• Optimized Head Design: The undercut flat head with a 100° countersink angle allows for a flush, low-profile installation, ideal for streamlined assemblies.
• Compliant for Global Use: Manufactured to be fully RoHS 3 and REACH compliant, meeting stringent international environmental and safety regulations.

Professional Applications & Engineering Value

This 4-40 UNC Flat Head Phillips Screw is engineered to solve critical sealing challenges in demanding industrial environments. The combination of 18-8 Stainless Steel and a passivated finish provides excellent resistance to corrosion, making it ideal for applications in chemical processing, marine, and outdoor equipment. The integrated silicone rubber O-ring is the key to its value, creating a hermetic seal that prevents fluid and gas leaks in high-pressure systems up to 6000 psi. Its undercut flat head design ensures a smooth, non-protruding finish, which is crucial for assemblies where space is limited or a clean aesthetic is required. This screw is a reliable solution for sealing fasteners in hydraulic systems, pneumatic controls, and precision instrumentation, ensuring long-term operational integrity and reducing maintenance needs.

Specification Summary & Compliance

This screw adheres to the UNC (Unified Coarse Thread) standard with a precise Class 2A thread fit for consistent and reliable engagement. The dimensional specifications, including a 3/4" length and No. 1 Phillips drive, are manufactured to exacting tolerances. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for use in regulated markets and sensitive applications.