S-91263A718 1/4"-28 x 5/8" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc plating for extended service life in harsh industrial environments
• Exceptional tensile strength of 130,000 psi ensures reliable performance in high-stress applications
• Precision Class 3A thread fit provides superior vibration resistance and secure fastening in critical assemblies
• 82° countersink angle design allows for flush mounting and clean aesthetic finishes
• Rockwell C39 hardness rating delivers excellent wear resistance and durability
• Hex drive compatibility enables efficient installation with standard industrial tools
• Full threading configuration ensures maximum grip length and holding power

Professional Applications & Engineering Value

These zinc-plated alloy steel flat head screws with 1/4"-28 UNF fine threads are engineered to address critical challenges in precision manufacturing and heavy-duty assembly. The combination of Class 3A thread fit and 130,000 psi tensile strength provides exceptional resistance to vibration loosening and mechanical stress, making them ideal for automotive components, machinery frames, and electronic enclosures where reliability is paramount. The 82° countersink angle ensures seamless flush mounting while the zinc plating offers superior protection against corrosion in demanding industrial environments. These fully threaded fasteners deliver consistent performance in applications requiring precise alignment and maximum clamping force.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread fit precision and UNF fine thread specifications. Compliant with ASTM F835 manufacturing standards, RoHS 3 (2015/863/EU) environmental directives, and REACH (EC 1907/2006) chemical safety regulations. Features 5/8" length with 0.25" thread diameter and right-hand threading for standardized industrial applications.