S-90429A126 5-40 x 1 1/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 psi ensures reliable, long-lasting fastening in demanding industrial environments.
• Corrosion-resistant Black-Oxide finish on alloy steel enhances durability and provides a professional, long-wearing appearance.
• Class 3A thread fit guarantees precise, high-quality engagement for secure assemblies and reduced risk of cross-threading.
• Partially threaded shank allows for controlled clamping force, preventing over-tightening and material damage.
• 82° countersink angle and flat head design enable a flush, clean finish for aerodynamic and safety-critical surfaces.
• Hex drive (5/64") offers superior torque transmission and slip resistance compared to standard slotted drives.
• Coarse UNC threads provide faster installation and superior performance in brittle materials or where vibration is a concern.

Professional Applications & Engineering Value

Engineered for precision and endurance, these 5-40 UNC flat head screws are the ideal solution for applications where material integrity and fastener reliability are non-negotiable. The Black-Oxide Alloy Steel construction provides a robust barrier against corrosion, extending service life in harsh conditions. The combination of a Class 3A thread fit and partial threading ensures a secure, vibration-resistant hold without stripping threads or deforming the host material. This makes them exceptionally valuable in industrial machinery, electronic enclosures, and automotive assemblies, where consistent performance under stress is critical. The hex drive and standard 82° countersink further streamline installation, saving time and labor while achieving a perfectly flush mount.

Specification Summary & Compliance

This screw adheres to high-precision manufacturing standards, including a Class 3A thread fit and UNC coarse thread profile. It is manufactured in compliance with ASME B18.3 and ASTM F835 specifications, ensuring dimensional accuracy and performance reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for use in regulated markets and sustainable manufacturing processes.