S-91255A313 1/2"-13 x 4" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish prolongs service life in harsh environments, minimizing maintenance and replacement costs.
• Precision Class 3A thread fit provides secure, vibration-resistant connections, enhancing assembly integrity and reducing loosening over time.
• Partially threaded design allows for controlled clamping force, ideal for applications where precise grip range is critical.
• Heavy-duty alloy steel construction with Rockwell C39 hardness offers excellent durability and wear resistance for long-term use.
• 5/16" hex drive enables easy installation and removal with standard tools, improving workflow efficiency in tight spaces.
• Coarse UNC threads facilitate quick engagement and disassembly, saving time in repetitive or high-volume assembly operations.

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these black-oxide alloy steel rounded head hex screws address common challenges like vibration-induced loosening and corrosion. The partially threaded UNC coarse thread design ensures optimal load distribution, making them ideal for heavy machinery, structural steel assemblies, and automotive applications where high tensile strength and Class 3A thread fit are critical. The black-oxide surface treatment provides an added layer of protection against moisture and chemicals, extending fastener life in outdoor or corrosive settings. By combining ASME B18.3 compliance with robust material properties, these screws deliver consistent performance in construction, manufacturing, and equipment maintenance, reducing downtime and enhancing operational reliability.

Specification Summary & Compliance

This screw features a 1/2"-13 UNC coarse thread with Class 3A precision fit and a minimum thread length of 1-1/2". Manufactured from high-strength alloy steel, it meets ASME B18.3 and ASTM F835 standards for dimensional accuracy and mechanical properties. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, ensuring adherence to environmental and safety regulations for industrial use.