S-91571A429 3/4"-10 x 5 1/4" ASME B18.2.6, ASTM A325, ASTM F3125 Medium-Strength Steel Heavy Hex Head Screws for Structural Applications

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 120,000 psi tensile strength for reliable performance in high-stress structural connections
• Superior corrosion resistance and durability through high-grade steel construction with Rockwell C19 hardness rating
• Optimized installation efficiency with external hex drive design providing secure tool engagement and torque application
• Enhanced vibration resistance through UNC coarse threading that maintains secure fastening in dynamic load conditions
• Precise thread engagement with Class 2A thread fit ensuring consistent assembly and reduced cross-threading risks
• Versatile application compatibility with partial threading design allowing for both clamping and alignment functions
• Regulatory compliance assurance meeting international standards including RoHS 3 and REACH for global project suitability

Professional Applications & Engineering Value

Engineered for demanding structural applications, these Grade A325 hex head screws deliver critical performance where failure is not an option. The heavy-duty steel construction combined with UNC coarse threading provides exceptional resistance to vibration loosening in construction, bridgework, and heavy machinery assemblies. The partial threading design allows the unthreaded shank to bear against connected members, preventing shear plane failures while the threaded portion ensures proper clamping force. With external hex drive configuration, installers achieve higher torque values without stripping, making these industrial fasteners ideal for bolted joints requiring predictable preload. The 1 3/8" thread length provides sufficient engagement in standard thickness materials while maintaining structural integrity.

Specification Summary & Compliance

Manufactured to precise inch system dimensions with Class 2A thread fit tolerance for consistent assembly performance. These 3/4"-10 UNC fasteners comply with ASME B18.2.6, ASTM A325, and ASTM F3125 specifications for structural bolting applications. The screws are fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting the latest environmental regulations for hazardous substances. The right-hand thread direction and coarse thread spacing provide industry-standard compatibility with existing infrastructure and tooling.