S-90185A256 5/8"-11 x 2 1/4" ASME B18.5, SAE J429 Carriage Bolts

Key Features & Benefits at a Glance

• Superior Anti-Rotation Performance: The integrated square neck design securely locks into materials, preventing bolt spin during installation and under vibration, ensuring reliable long-term fastening.
• Exceptional Tensile Strength for Demanding Applications: With a 120,000 psi tensile strength and Grade 5 classification, this bolt is engineered to handle high-stress loads in structural and heavy machinery assemblies.
• Enhanced Corrosion Resistance: The zinc-plated steel construction provides a protective barrier against rust and corrosion, extending the service life of the fastener in various industrial environments.
• Optimized for Quick and Secure Installation: The fully threaded UNC coarse thread pattern allows for faster driving and a stronger grip in wood and soft materials, reducing assembly time.
• Precision Thread Fit for Reliable Engagement: Manufactured to Class 3A thread fit tolerances, ensuring consistent, high-quality thread mating with nuts for a secure and vibration-resistant connection.
• High Durability and Material Integrity: A Rockwell C25 hardness rating guarantees the bolt can withstand significant shear and tensile forces without deforming or failing.
• Rounded Head for Safety and Aesthetics: The wide, rounded carriage head style sits flush against surfaces, minimizing snagging hazards and providing a clean, finished look.

Professional Applications & Engineering Value

This Grade 5 zinc-plated steel carriage bolt is engineered to solve critical challenges in industrial and construction settings. Its square neck is a key engineering feature that bites into the mounting material, effectively eliminating rotation during nut tightening and under operational stress, which is a common failure point in dynamic environments. The combination of high tensile strength (120,000 psi) and a coarse UNC thread makes it exceptionally suitable for heavy-duty applications like structural framing, trailer assembly, and agricultural equipment, where it must resist shock, vibration, and heavy loading. The zinc plating offers essential corrosion protection, making it a reliable choice for both indoor and outdoor applications, ensuring long-term structural integrity and reducing maintenance cycles.

Specification Summary & Compliance

This carriage bolt conforms to critical dimensional and performance standards, including ASME B18.5. The threading is precision-manufactured to UNC coarse specifications with a Class 3A thread fit for superior engagement. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for use in regulated markets.