S-91253A322 1/4"-28 x 2 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments.
• High tensile strength of 130,000 psi ensures reliable performance under heavy loads and vibration.
• Precise Class 3A thread fit provides superior engagement and reduces the risk of cross-threading.
• 82° countersink angle and flat head design allow for a flush, secure fit in countersunk applications.
• Hex drive (5/32") offers high torque transmission and easy installation with standard tools.
• Partially threaded shank enables better clamping force on specific material thicknesses.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees material quality and environmental safety.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these 1/4"-28 UNF flat head screws in black-oxide alloy steel address common challenges like material fatigue and environmental exposure. The fine thread spacing and Class 3A thread fit ensure tight, vibration-resistant connections in machinery, automotive assemblies, and metal frameworks. The partially threaded design concentrates clamping force, preventing joint loosening, while the 82° countersink angle provides a seamless finish. With a Rockwell C39 hardness and high tensile strength, they deliver long-term reliability in high-stress environments, reducing maintenance needs and downtime.

Specification Summary & Compliance

This screw features a 1/4"-28 UNF thread with Class 3A fit and fine thread spacing, ensuring precise dimensional accuracy. It meets ASTM F835 specifications for mechanical properties and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming adherence to environmental and safety standards.