S-91253A308 1/4"-28 x 7/16" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Superior thread engagement with Class 3A fit and UNF fine threading for vibration-resistant, secure fastening
• High tensile strength of 130,000 psi ensures reliable performance under heavy loads and stress conditions
• Optimized flush mounting with 82° countersink angle and flat head design for smooth surface finishes
• Enhanced torque transmission through 5/32" hex drive, preventing stripping during installation
• Full threading along 7/16" length provides maximum grip depth and adjustment flexibility
• Industry compliance assurance with ASTM F835 standards and environmental regulations (RoHS 3/REACH)

Professional Applications & Engineering Value

Engineered for precision assembly requirements, these Black-Oxide Alloy Steel flat head screws deliver critical advantages in machinery, automotive, and equipment manufacturing. The Class 3A UNF fine threads maintain clamping force in high-vibration applications, while the 82° countersink ensures seamless integration with mating surfaces. With 130,000 psi tensile strength and Rockwell C39 hardness, these fully threaded hex drive screws withstand extreme mechanical stresses without compromising integrity. The corrosion-resistant coating combined with ASTM F835 compliance makes them ideal for regulated industries requiring durable inch fasteners with documented performance standards.

Specification Summary & Compliance

This 1/4"-28 UNF flat head screw maintains Class 3A thread tolerances with right-hand fine threading and fully threaded 7/16" length. Manufactured to ASTM F835 specifications with Rockwell C39 hardness verification. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for hazardous substance restrictions.