S-91263A556 1/4"-20 x 5/8" 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 for heavy-duty applications, preventing fastener failure under high stress
• Precise Class 3A thread fit for secure, vibration-resistant assemblies that maintain integrity over time
• 82° countersink angle flat head design allows for flush mounting, reducing snagging and improving safety
• Hex drive (5/32") compatibility enables easy installation with standard tools, saving time and labor costs
• Full UNC coarse threading provides quick engagement and strong holding power in various materials
• Compliance with ASTM F835, RoHS 3, and REACH ensures regulatory adherence for global industrial use

Professional Applications & Engineering Value

This zinc-plated alloy steel flat head screw is engineered to address common industrial challenges like vibration loosening and corrosion in demanding environments. The UNC coarse thread and Class 3A fit deliver reliable performance in machinery, automotive, and structural assemblies, where precise tolerances are critical. With a Rockwell C39 hardness and 130,000 psi tensile strength, it withstands heavy loads and repetitive stress, reducing maintenance needs. The 82° countersink angle ensures a smooth, flush finish, minimizing protrusion risks in confined spaces. Ideal for industrial fastening applications requiring durability and compliance, this screw offers long-term value by enhancing assembly integrity and operational safety.

Specification Summary & Compliance

This product features precise UNC coarse threading with Class 3A fit and a 5/8" length, manufactured to ASTM F835 specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental and safety standards are met for industrial use.