S-91286A344 1/2"-13 x 4" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 150,000 psi tensile strength for demanding structural and machinery applications
• Superior corrosion resistance provided by zinc-flake coating, extending service life in harsh industrial environments
• Reliable thread engagement through Class 2A thread fit and UNC coarse threading, ensuring secure fastening and vibration resistance
• Optimized torque transmission via external hex drive and 3/4" head width, enabling efficient installation with standard tools
• Controlled clamping force through partial threading design, preventing over-tightening in critical assemblies
• Consistent mechanical performance backed by Grade 8 certification and Rockwell C33 hardness for predictable behavior under stress
• Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards for global project specifications

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Grade 8 hex head screws deliver critical performance where structural integrity is paramount. The zinc-flake coated steel construction provides superior corrosion protection for outdoor equipment, construction machinery, and manufacturing systems exposed to environmental challenges. The 1/2"-13 UNC coarse threading ensures rapid assembly and superior resistance to vibrational loosening in dynamic load conditions. With partial threading design, these fasteners provide precise clamp force control for critical joints in structural steel connections, heavy equipment manufacturing, and industrial machinery assembly. The combination of 150,000 psi tensile strength and Rockwell C33 hardness makes these screws ideal for high-stress applications where fastener failure is not an option.

Specification Summary & Compliance

This 4" length hex head screw features precise Class 2A thread fit tolerances and UNC coarse threading standards for consistent performance. Manufacturing complies with ASME B18.2.1 and SAE J429 Grade 8 specifications, ensuring dimensional accuracy and mechanical properties. The product meets RoHS 3 (2015/863/EU) compliance for hazardous substance restrictions and REACH (EC 1907/2006) standards for chemical safety, making it suitable for regulated industries and international projects.