S-91253A377 1/2"-20 x 1 1/2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
• Exceptional tensile strength (130,000 psi) prevents stripping and failure under high-stress applications
• Precision Class 3A thread fit ensures secure fastening with minimal vibration loosening
• 82° countersink angle provides flush mounting for clean, professional finishes
• Fully threaded design offers maximum grip length and load distribution
• 5/16" hex drive enables high-torque installation with standard tools
• Rockwell C39 hardness maintains thread integrity through repeated use

Professional Applications & Engineering Value

These black-oxide alloy steel flat head screws deliver critical performance where high tensile strength and corrosion resistance are paramount. The Class 3A UNF fine threads provide superior engagement in precision machinery, automotive assemblies, and heavy equipment where vibration resistance is essential. The 82° countersink creates seamless surfaces in aerospace components and industrial enclosures, while the fully threaded design ensures maximum clamping force across the entire fastener length. Engineered to withstand extreme mechanical stresses while maintaining thread integrity through Rockwell C39 hardness, these screws solve common failure points in high-vibration environments.

Specification Summary & Compliance

Manufactured to ASME B18.3 and ASTM F835 specifications with Class 3A thread fit precision. Features 1/2"-20 UNF fine threads with right-hand orientation and 1 1/2" length. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for industrial use.