S-90275A113 4-40 x 3/4" ASME B18.6.3 Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with zinc-plated steel coating, extending service life in demanding environments
• High tensile strength of 60,000 psi ensures reliable fastening under mechanical stress and vibration
• Rockwell B70 hardness provides excellent wear resistance and durability for repeated use
• Fully threaded design offers maximum grip and holding power along the entire screw length
• Standard 82° countersink angle allows for flush mounting, reducing snagging and improving aesthetics
• Class 2A thread fit ensures easy assembly while maintaining secure connections in inch-system applications
• Compliance with ASME B18.6.3 guarantees consistent quality and dimensional accuracy for industrial use

Professional Applications & Engineering Value

These 4-40 UNC flat head slotted screws are engineered to address common industrial fastening challenges, particularly where space constraints and corrosion resistance are critical. The zinc-plated steel construction provides a protective barrier against oxidation, making them ideal for machinery, electrical enclosures, and outdoor equipment. The coarse UNC threading and right-hand thread direction facilitate quick installation in soft materials and blind assemblies, while the flat head design with standard profile ensures a secure, flush fit that prevents protrusion in tight spaces. With full threading along the 3/4" length, these screws deliver uniform clamping force, reducing the risk of loosening in high-vibration environments common in manufacturing and automotive applications.

Specification Summary & Compliance

These screws feature precise Class 2A thread fit per UNC standards, ensuring consistent engagement and ease of assembly. Manufacturing adheres to ASME B18.6.3 specifications for dimensional accuracy, including head diameter (0.212"), head height (0.067"), and thread size (4-40). The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances for safe use in global markets.