S-91253A358 5/16"-24 x 2 1/4" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating for prolonged service life in demanding environments
• Superior tensile strength (130,000 psi) ensures reliable performance under heavy loads and vibration
• Precision Class 3A thread fit provides secure, vibration-resistant connections with minimal play
• 82° countersink angle design allows for flush mounting and clean aesthetic finishes
• Hex drive compatibility (3/16") enables high-torque installation with standard industrial tools
• Fine thread spacing (24 TPI) delivers enhanced clamping force and superior resistance to loosening
• Rockwell C39 hardness rating maintains thread integrity and prevents stripping during repeated use

Professional Applications & Engineering Value

These black-oxide alloy steel flat head screws deliver critical performance advantages in industrial assembly applications where vibration resistance and corrosion protection are paramount. The combination of UNF fine threading with Class 3A fit ensures precise engagement in machinery, automotive components, and heavy equipment where tolerance control is essential. The partially threaded design provides optimal clamping force distribution, while the 82° countersink angle creates seamless transitions in precision-machined surfaces. Engineered to withstand extreme mechanical stress with 130,000 psi tensile strength, these fasteners solve common failure points in high-vibration environments while maintaining compliance with rigorous industrial standards.

Specification Summary & Compliance

Manufactured to exact Class 3A thread fit tolerances with 5/16"-24 UNF fine threading and standardized 82° countersink angle. Full compliance with ASTM F835 specifications for mechanical properties and dimensional requirements. Meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance standards for industrial use.