S-91253A363 5/16"-24 x 3" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Class 3A thread fit provides superior precision and tighter tolerances for secure, vibration-resistant assemblies in critical machinery and equipment.
• Black-oxide finish on alloy steel offers enhanced corrosion resistance and a durable, non-reflective surface ideal for harsh industrial environments.
• Partially threaded design with 82° countersink angle allows for flush mounting and improved load distribution, minimizing surface protrusion and enhancing aesthetic integration.
• Rockwell C39 hardness delivers excellent wear resistance and long-term durability, maintaining fastener integrity through repeated use.
• UNF fine threading ensures better engagement and holding power in materials where coarse threads may not be suitable, providing a secure fit.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees that these screws meet rigorous industry standards for safety, environmental responsibility, and material quality.

Professional Applications & Engineering Value

These 5/16"-24 UNF flat head screws are engineered to address common industrial challenges such as vibration loosening, corrosion, and precise flush mounting requirements. The Black-Oxide Alloy Steel construction provides a robust barrier against rust and wear, making them ideal for applications in automotive assemblies, heavy machinery, and electronic enclosures where exposure to moisture and chemicals is a concern. The Class 3A thread fit and fine UNF threading ensure tight, reliable connections that resist back-out under dynamic loads, while the 82° countersink angle facilitates seamless integration into surfaces, reducing the risk of snagging and improving safety. This combination of material strength, precise thread form, and compliant design makes these screws a trusted choice for engineers seeking durability and performance in industrial fastening solutions.

Specification Summary & Compliance

These screws feature a Class 3A thread fit with precise UNF fine threading (5/16"-24) and a minimum thread length of 1 1/8", ensuring high accuracy and reliability. They are manufactured in accordance with ASTM F835 specifications and comply with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, confirming their adherence to environmental and safety regulations for industrial use.