S-91781A117 4-40 x 1 1/4" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 stainless steel and passivated finish for extended service life in harsh environments.
• High tensile strength of 80,000 psi ensures reliable fastening under significant mechanical stress.
• Rockwell B80 hardness provides excellent durability and resistance to wear and deformation.
• Class 2A thread fit offers consistent, reliable assembly with standard UNC coarse threads for quick installation.
• 82° countersink angle and flat head design allows for a flush, secure fit in tapered seats, minimizing protrusion.
• Full threading along the 1-1/4" length ensures maximum grip and uniform load distribution.
• Compliance with ASME B18.6.3, RoHS 3, and REACH guarantees quality, safety, and environmental standards for industrial use.

Professional Applications & Engineering Value

These 4-40 UNC flat head slotted screws are engineered to address common industrial challenges such as vibration loosening and corrosion. Made from 18-8 stainless steel with a passivated finish, they resist rust and chemical exposure, making them ideal for machinery, electronics, and outdoor equipment. The coarse UNC threads and Class 2A fit provide quick, secure fastening in materials like metal and plastic, reducing assembly time. The flat head with an 82° countersink ensures a smooth surface finish, preventing snagging and improving aesthetics in visible applications. With full threading, they offer consistent clamping force, essential for maintaining integrity in dynamic loads.

Specification Summary & Compliance

This product adheres to precise dimensional standards, including Class 2A thread fit and UNC coarse threads with a size of 4-40. It meets ASME B18.6.3 specifications for manufacturing consistency and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring no hazardous substances and environmental safety in industrial applications.