S-90275A131 5-40 x 3/4" ASME B18.6.3 Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable load-bearing capacity and prevents fastener failure under stress
• Rockwell B70 hardness provides excellent wear resistance and maintains thread integrity during repeated use
• Class 2A thread fit offers consistent, easy assembly with standard UNC coarse threads for quick installation
• 82° countersink angle with standard flat head profile enables flush mounting for a smooth, professional finish
• Full threading along the 3/4" length maximizes grip and distribution of clamping force across the entire fastener
• Compliance with ASME B18.6.3, RoHS 3, and REACH guarantees industry-standard quality and environmental safety

Professional Applications & Engineering Value

These 5-40 UNC flat head slotted screws are engineered to address critical fastening challenges in industrial settings. The zinc-plated steel material provides a durable barrier against rust and corrosion, making them ideal for machinery, electrical enclosures, and outdoor equipment where environmental exposure is a concern. The coarse UNC threads and Class 2A fit ensure quick, secure installation with standard tools, reducing assembly time and minimizing cross-threading risks. The flat head design with an 82° countersink allows for seamless integration into surfaces, preventing snagging and maintaining aerodynamic or aesthetic profiles. With a tensile strength of 60,000 psi and Rockwell B70 hardness, these screws withstand vibration and heavy loads, offering long-term reliability in automotive, aerospace, and construction applications.

Specification Summary & Compliance

This product adheres to Class 2A thread fit per UNC standards, ensuring precise dimensional accuracy and interchangeability. Manufacturing and quality are governed by ASME B18.6.3 specifications, covering head profile, drive style, and thread geometry. Environmental and safety compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), confirming the absence of restricted hazardous substances. The screws are fully threaded, right-hand oriented, and designed for consistent performance in industrial fastening systems.