S-90185A118 5/16"-18 x 4" ASME B18.5, SAE J429 Carriage Bolts

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with 120,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance from black-oxide steel finish, extending service life in harsh environments
• Secure anti-rotation design with integrated square neck that prevents spinning during installation
• Optimized thread engagement through Class 2A fit UNC coarse threading for faster assembly and vibration resistance
• Enhanced durability with Rockwell C25 hardness rating, maintaining structural integrity under stress
• Versatile rounded head profile with wide bearing surface for reduced surface damage and improved aesthetics
• Full-threaded construction providing maximum grip length and flexibility in material thickness applications

Professional Applications & Engineering Value

This Grade 5 carriage bolt delivers critical engineering solutions where vibration resistance and structural integrity are paramount. The black-oxide steel construction provides essential corrosion protection for outdoor equipment, agricultural machinery, and structural frameworks exposed to environmental elements. The square neck design effectively eliminates rotation during torque application, significantly reducing installation time and preventing damage to connected materials. With its 5/16-18 UNC coarse threading and Class 2A thread fit, this fastener ensures rapid assembly in wood-to-metal and structural steel applications while maintaining consistent clamping force. The combination of 120,000 psi tensile strength and Rockwell C25 hardness makes it ideal for heavy-duty construction, trailer manufacturing, and industrial equipment where dynamic loads and stress cycling occur.

Specification Summary & Compliance

This carriage bolt features precision 5/16-18 UNC coarse threads with Class 2A fit tolerance ensuring consistent thread engagement. Manufactured to meet ASME B18.5 and SAE J429 Grade 5 specifications for dimensional accuracy and mechanical properties. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for regulated industries and international projects requiring certified components.