S-91266A597 5/16"-24 x 1 1/2" ASTM F835 Alloy Steel Thread-Locking Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Permanent vibration resistance with nylon patch locking technology that maintains secure fastening in high-stress environments
• Superior corrosion protection through black-oxide coating on alloy steel, extending service life in demanding conditions
• Exceptional tensile strength rated at 130,000 psi for reliable performance in heavy-duty applications
• Precise thread engagement with Class 3A fit ensuring consistent, reliable connections in critical assemblies
• Wide temperature tolerance from -65° to 250° F for stable performance across diverse operating environments
• Maximum holding power through full threading along the entire 1-1/2" length for superior load distribution
• Industry compliance assurance meeting ASTM F835 specifications for quality and performance reliability

Professional Applications & Engineering Value

These 5/16"-24 UNF flat head screws with nylon patch locking technology address critical vibration-induced loosening in industrial machinery, automotive assemblies, and heavy equipment. The black-oxide alloy steel construction provides excellent corrosion resistance while maintaining the 130,000 psi tensile strength necessary for structural applications. The Class 3A thread fit ensures precise engagement in tapped holes, reducing the risk of cross-threading during installation. The fully threaded design maximizes surface contact for superior clamping force distribution, making these flat head screws ideal for applications requiring flush mounting with countersunk surfaces. The combination of high-strength material and permanent locking mechanism delivers reliable performance in environments subject to thermal cycling and mechanical stress.

Specification Summary & Compliance

Manufactured to exacting standards with Class 3A thread fit precision and UNF fine threading (5/16"-24) for superior engagement. These screws comply with ASTM F835 specifications for mechanical properties and performance. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring they meet international environmental standards. The 82° countersink angle provides proper seating in standard countersunk holes, while the Rockwell C39 hardness rating confirms appropriate material strength for demanding fastener applications.