S-90429A124 4-48 x 3/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength (130,000 psi) for reliable performance in high-stress industrial applications
• Superior corrosion resistance with black-oxide coating on alloy steel, extending service life in demanding environments
• Precision Class 3A thread fit ensures tight, secure fastening with minimal vibration loosening
• Full threading provides maximum grip length and uniform load distribution across the entire fastener
• 82° countersink angle allows for flush mounting in standard recessed applications
• Hex drive design (1/16") enables high-torque installation without cam-out risks
• Fine UNF threading delivers superior holding power compared to coarse thread alternatives

Professional Applications & Engineering Value

These 4-48 UNF flat head screws with black-oxide alloy steel construction address critical engineering challenges in precision assembly applications. The combination of Rockwell C39 hardness and 130,000 psi tensile strength provides exceptional resistance to shear forces and fatigue failure in machinery, aerospace components, and electronic enclosures. The fine threading and Class 3A fit ensure vibration-resistant fastening in dynamic systems, while the 82° countersink angle creates seamless surface finishes in precision instruments and automotive assemblies. The hex drive system allows for controlled installation torque, preventing damage to sensitive components during assembly operations.

Specification Summary & Compliance

Manufactured to exacting Class 3A thread fit tolerances with UNF fine threading (4-48) and 82° countersink angle. Fully compliant with ASME B18.3 dimensional standards and ASTM F835 mechanical properties. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for restricted substance control.