S-91306A255 4-40 x 3/4" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with zinc-plated alloy steel construction for long-lasting performance in harsh industrial environments
• Superior load-bearing capability with 120,000 psi tensile strength ensuring reliable fastening under high-stress conditions
• Precise thread engagement with Class 3A fit providing secure, vibration-resistant connections in critical assemblies
• Optimized installation efficiency through 1/16" hex drive design allowing quick, secure tool engagement without cam-out
• Enhanced durability with Rockwell C39 hardness maintaining structural integrity through repeated use cycles
• Versatile coarse threading with UNC 4-40 profile enabling rapid installation and superior pull-out resistance
• Comprehensive compliance meeting ASME B18.3 and ASTM F835 specifications for guaranteed engineering consistency

Professional Applications & Engineering Value

These 4-40 UNC rounded head screws deliver critical engineering solutions where corrosion resistance and high tensile strength are paramount. The zinc-plated alloy steel construction provides superior protection against environmental degradation, while the fully threaded design ensures maximum grip length in thin-section materials. The button head profile with standard rounded contour offers low-profile fastening ideal for assemblies requiring flush mounting without sharp edges. Particularly valuable in industrial equipment, electronic enclosures, and machinery where Class 3A thread fit guarantees precise, vibration-resistant connections. The coarse UNC threading enables rapid installation in production environments while maintaining exceptional pull-out performance in metal-to-metal applications.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit per UNC specifications, ensuring consistent engagement and optimal clamping force. Compliant with ASME B18.3 and ASTM F835 manufacturing standards for guaranteed dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance requirements, confirming absence of restricted substances. Features right-hand coarse threading with full 3/4" length and standardized 1/16" hex drive configuration for universal tool compatibility.