S-91266A709 1/2"-13 x 3/4" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Vibration-resistant locking with Nylon Patch thread locker prevents loosening in demanding environments from -65° to 250°F
• Exceptional tensile strength of 130,000 psi ensures reliable performance in heavy-duty and high-stress applications
• Precise Class 3A thread fit provides superior engagement and reduces the risk of cross-threading during assembly
• Corrosion-resistant black-oxide finish on alloy steel enhances durability and extends service life in industrial settings
• Secure hex drive (5/16") allows for high-torque installation with standard tools, minimizing slippage and tool wear
• Standard 82° countersink angle enables flush mounting for a clean, professional finish in machined surfaces
• Full threading along the 3/4" length ensures maximum grip and uniform load distribution across the fastened materials

Professional Applications & Engineering Value

Engineered for industrial and heavy machinery applications, these black-oxide alloy steel flat head screws address critical challenges in vibration-prone environments. The Nylon Patch thread locker effectively counters loosening caused by dynamic loads and thermal cycling, maintaining clamp force integrity from sub-zero to elevated temperatures. With a coarse UNC thread and Class 3A fit, installation is swift and reliable, reducing assembly errors in production lines. The hex drive design supports high torque application, ideal for construction equipment, automotive assemblies, and metal fabrication where disassembly is infrequent but security is paramount. The combination of 130,000 psi tensile strength and Rockwell C39 hardness ensures these fasteners withstand shear and tensile stresses without deformation, providing long-term reliability in structural connections.

Specification Summary & Compliance

This 1/2"-13 UNC flat head screw features a Class 3A thread fit with coarse spacing, ensuring precise dimensional accuracy per unified thread standards. Manufacturing adheres to ASTM F835 specifications for mechanical properties and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted substances and supporting environmentally conscious procurement. Additional specifications include a 0.938" head diameter, 82° countersink angle, and fully threaded 3/4" length for consistent application across industrial fastening requirements.