S-91266A086 2-56 x 3/8" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior vibration resistance with nylon patch thread locker that maintains integrity from -65° to 250°F
• Exceptional tensile strength of 130,000 psi ensures reliable performance in high-stress applications
• Precise Class 3A thread fit provides superior engagement and reduces cross-threading risks
• Corrosion-resistant black-oxide coating on alloy steel extends service life in demanding environments
• Optimized 82° countersink angle enables flush mounting for clean, professional installations
• Hex drive design delivers superior torque transmission and prevents tool slippage
• Full threading along the entire 3/8" length ensures maximum holding power

Professional Applications & Engineering Value

These 2-56 UNC flat head screws with black-oxide alloy steel construction address critical industrial fastening challenges where vibration resistance and material integrity are paramount. The combination of Class 3A thread fit and nylon patch thread locker creates a permanent locking solution that withstands extreme temperature fluctuations from -65° to 250°F, making them ideal for automotive assemblies, electronic enclosures, and machinery where thermal cycling occurs. The hex drive configuration ensures secure installation in confined spaces while the 82° countersink angle provides seamless integration into precision components. With fully threaded design and Rockwell C39 hardness, these screws deliver consistent clamping force and prevent loosening under dynamic loads, significantly reducing maintenance requirements in industrial equipment and manufacturing systems.

Specification Summary & Compliance

These flat head screws feature precise Class 3A thread fit per UNC standards with 2-56 thread size and coarse thread spacing. Manufacturing complies with ASTM F835 specifications, ensuring dimensional accuracy and performance reliability. The products are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, meeting the latest industry standards for hazardous substance restrictions and chemical safety protocols.