S-96640A231 4-40 x 7/8" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with Black-Oxide 18-8 Stainless Steel construction, ideal for harsh environments and extended service life.
• High tensile strength of 80,000 psi ensures reliable, secure fastening under demanding mechanical loads.
• Rockwell B80 hardness provides excellent durability and resistance to wear and deformation.
• Fully threaded design with UNC coarse thread offers maximum grip and faster installation in a variety of materials.
• Standard 82° countersink angle and flat head allows for a flush, clean finish, reducing snagging and improving safety.
• Class 2A thread fit ensures consistent, easy assembly with standard nuts and tapped holes, minimizing production delays.
• Phillips drive (No. 1 size) enables efficient driving with common tools, enhancing installation speed and reducing slippage.

Professional Applications & Engineering Value

These 4-40 UNC flat head Phillips screws are engineered to address critical industrial fastening challenges. The Black-Oxide 18-8 Stainless Steel material provides exceptional corrosion resistance, making them suitable for applications in moist or chemically aggressive environments, such as outdoor equipment, marine hardware, and electronic enclosures. The fully threaded coarse UNC thread and Class 2A fit ensure quick, reliable engagement in metals and plastics, reducing the risk of cross-threading and improving assembly efficiency. With an 82° countersink angle, these screws sit flush to prevent protrusion, which is vital in machinery and automotive components where smooth surfaces are necessary to avoid interference and enhance safety. Their high tensile strength and hardness support long-term performance in industrial applications requiring vibration resistance and structural integrity.

Specification Summary & Compliance

This product features precise Class 2A thread fit per UNC standards, ensuring dimensional accuracy and interchangeability. It is manufactured in compliance with ASME B18.6.3 specifications for consistent quality and performance. Additionally, these screws meet RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulatory requirements, confirming they are free of hazardous substances and safe for use in various global markets.