S-91253A107 4-40 x 5/16" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• Superior tensile strength of 130,000 psi ensures reliable performance under high-stress conditions
• Precise Class 3A thread fit provides secure fastening with minimal risk of loosening
• Fully threaded coarse spacing allows for faster installation and improved grip in various materials
• 82° countersink angle enables flush mounting for a clean, professional finish
• Hex drive design offers easy installation with standard tools, reducing assembly time
• High hardness (Rockwell C39) increases durability and resistance to wear over time

Professional Applications & Engineering Value

This 4-40 UNC flat head screw is engineered from black-oxide alloy steel to address common industrial challenges such as corrosion and mechanical failure. The fully threaded coarse spacing and Class 3A thread fit ensure tight, secure connections in applications like machinery assembly, electronics enclosures, and automotive components, where vibration resistance is critical. The 82° countersink angle allows for seamless integration into surfaces, preventing protrusion and enhancing safety. Its hex drive facilitates quick installation, reducing labor costs and improving efficiency in high-volume production environments.

Specification Summary & Compliance

This screw features a 4-40 UNC thread size with Class 3A thread fit for precise dimensional accuracy. It complies with ASME B18.3 and ASTM F835 manufacturing standards, ensuring consistent quality. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial use.