S-91253A097 3-56 x 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 performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Class 3A thread fit precision provides tighter tolerances for superior thread engagement, minimizing backlash and improving assembly accuracy.
• Black-oxide finish on alloy steel offers enhanced corrosion resistance, extending service life in harsh industrial environments.
• Fully threaded design with UNF fine threads delivers maximum grip and vibration resistance, ideal for securing components in precision machinery.
• Hex drive compatibility (1/16") allows for efficient installation with standard tools, speeding up assembly processes and reducing labor time.
• 82° countersink angle and flat head profile enable flush mounting, preventing protrusions and ensuring a smooth, aerodynamic surface in finished products.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees adherence to international safety and environmental standards, supporting sustainable procurement practices.

Professional Applications & Engineering Value

Engineered for precision fastening in industrial settings, these 3-56 UNF flat head screws address critical challenges like vibration loosening and material fatigue. The black-oxide alloy steel construction, combined with a Rockwell C39 hardness, ensures durability against wear and environmental exposure, making them suitable for electronics, automotive assemblies, and aerospace components. The fine thread spacing and Class 3A thread fit enhance load distribution, reducing stress concentrations in high-cycle applications. With a fully threaded design and right-hand thread direction, they provide consistent clamping force, ideal for securing sensitive parts where reliability is paramount. This screw type excels in scenarios requiring flush mounting and robust performance under dynamic loads.

Specification Summary & Compliance

This product maintains precise dimensional accuracy with a Class 3A thread fit per UNF standards, ensuring tight tolerances for secure fastening. It adheres to ASTM F835 specifications for mechanical properties and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of hazardous substances. The screw features a standard 82° countersink angle and is manufactured to deliver consistent performance in industrial applications.