S-91263A383 4-48 x 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength (130,000 psi) ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc-plated alloy steel construction, extending service life in demanding industrial environments.
• Precision Class 3A fine threads provide a tighter, more secure fit with reduced risk of cross-threading during assembly.
• 82° countersink angle and flat head design allow for a flush, low-profile installation ideal for streamlined surfaces.
• Fully threaded shank offers maximum grip and holding power along the entire length for enhanced joint integrity.
• Hex drive compatibility (1/16") enables efficient installation and removal with standard tools, speeding up assembly processes.
• High hardness rating (Rockwell C39) ensures excellent wear resistance and durability under repetitive use.

Professional Applications & Engineering Value

These 4-48 UNF flat head screws are engineered to address critical challenges in precision assembly and high-vibration environments. The zinc-plated alloy steel construction provides robust protection against corrosion, making them ideal for automotive, aerospace, and electronics applications where exposure to harsh conditions is common. The Class 3A fine thread specification ensures minimal play and superior clamping force, effectively preventing loosening in dynamic loads. With an 82° countersink angle, these screws sit flush with surfaces, eliminating protrusions that could interfere with moving parts or aesthetic requirements. Their fully threaded design maximizes engagement in thin materials, offering reliable fastening solutions for machinery, enclosures, and structural components where space and reliability are paramount.

Specification Summary & Compliance

This screw adheres to UNF thread standards with a Class 3A thread fit for high precision and consistent performance. It meets ASTM F835 specifications for mechanical properties and dimensional accuracy. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for global industrial use.