S-91263A376 4-40 x 1/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated alloy steel construction, ensuring long-term reliability in harsh industrial environments.
• Exceptional tensile strength of 130,000 psi provides reliable fastening under high-stress conditions, reducing the risk of fastener failure.
• Precise Class 3A thread fit ensures tight, secure connections with minimal backlash for improved assembly accuracy.
• Fully threaded design offers consistent grip along the entire length, enhancing load distribution and vibration resistance.
• Standard 82° countersink angle allows for flush mounting, creating a smooth surface finish and reducing snag hazards.
• Hex drive compatibility (1/16") enables easy installation with common tools, speeding up assembly processes.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees adherence to industry standards for safety and environmental responsibility.

Professional Applications & Engineering Value

These 4-40 UNC flat head screws are engineered to address critical fastening challenges in demanding industrial settings. The zinc-plated alloy steel material combats corrosion, extending service life in moisture-prone applications like outdoor equipment or machinery. With a coarse thread spacing and Class 3A thread fit, they provide superior holding power in soft materials or where vibration loosening is a concern, such as in automotive assemblies or electronic enclosures. The fully threaded design ensures maximum engagement, distributing stress evenly to prevent joint failure. Ideal for industrial fastening solutions requiring high strength and durability, these screws deliver consistent performance in manufacturing, aerospace, and construction projects, minimizing maintenance and downtime.

Specification Summary & Compliance

This screw features precise UNC thread specifications with a Class 3A thread fit for tight tolerances and reliable performance. Dimensions include a 1/4" length, 4-40 thread size, and standard flat head profile with an 82° countersink angle. It meets ASTM F835 standards for mechanical properties and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity.