S-91306A404 5/16"-18 x 1 1/4" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated alloy steel construction for extended service life in harsh industrial environments
• Exceptional mechanical strength with 120,000 psi tensile strength and Rockwell C39 hardness to withstand heavy loads and vibration
• Precision thread engagement with Class 3A UNC coarse threads ensuring reliable fastening and reduced cross-threading risks
• Optimized drive performance featuring hex drive design for high-torque applications and secure installation
• Versatile rounded button head profile providing a low-profile finish while distributing clamping force effectively
• Full threading along 1-1/4" length enabling maximum grip range and adjustment flexibility in assembled components
• Regulatory compliance assurance meeting ASME B18.3, ASTM F835, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this zinc-plated alloy steel rounded head hex screw addresses critical challenges in machinery assembly, structural frameworks, and heavy equipment manufacturing. The Class 3A UNC coarse thread configuration ensures rapid installation and superior resistance to vibrational loosening, while the fully threaded design provides consistent clamping force across the entire engagement length. The hex drive system accommodates high torque requirements without stripping, making it ideal for maintenance-critical applications where reliability is paramount. Combined with exceptional corrosion resistance from zinc plating, this fastener delivers long-term performance in environments exposed to moisture, chemicals, and temperature variations, reducing maintenance frequency and total cost of ownership.

Specification Summary & Compliance

This 5/16"-18 x 1-1/4" rounded head hex screw features precision UNC coarse threads with Class 3A thread fit tolerance for optimal engagement. Manufacturing complies with ASME B18.3 dimensional standards and ASTM F835 mechanical properties. The product is fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting current environmental regulations for industrial use.