S-93548A551 1/4"-20 x 2 1/4" ASTM A307, SAE J429, ASME B18.5 Carriage Bolts

Key Features & Benefits at a Glance

• Superior anti-rotation performance with a square neck design that locks securely into materials, preventing the bolt from turning during installation and under vibration.
• Enhanced corrosion resistance provided by the zinc-plated steel finish, extending service life in demanding industrial and construction environments.
• Reliable high-strength fastening with a Grade 2 classification and 60,000 psi tensile strength, ensuring dependable performance for heavy-duty applications.
• Excellent material hardness rated at Rockwell B70, providing increased durability and resistance to wear and deformation.
• Easy and quick installation facilitated by the coarse UNC 1/4"-20 thread and right-hand threading, compatible with standard tools and common assembly practices.
• Wide application compatibility due to the rounded carriage head style, which sits flush in countersunk holes and distributes load effectively.
• Full compliance with major industry standards including ASTM A307 and SAE J429, ensuring consistent quality and material integrity.

Professional Applications & Engineering Value

This zinc-plated steel carriage bolt is engineered to solve critical challenges in construction, machinery assembly, and structural framing where vibration resistance and joint integrity are paramount. The square neck is a key engineering feature that bites into the substrate, providing superior anti-rotation performance that eliminates the need for additional locking mechanisms. The Grade 2 strength and 60,000 psi tensile strength ensure it can handle significant shear and tensile loads, while the coarse UNC thread offers excellent grip in wood, metal, and other common materials. The zinc plating provides a protective barrier against rust and corrosion, making it ideal for outdoor equipment, agricultural machinery, and industrial frameworks exposed to harsh environmental conditions.

Specification Summary & Compliance

This carriage bolt features a 1/4"-20 UNC coarse thread with a Class 2A thread fit for standard tolerance and easy assembly. It is manufactured from zinc-plated steel and conforms to ASTM A307 and SAE J429 Grade 2 specifications for material and mechanical properties. The product is fully RoHS 3 (2015/863/EU) Compliant and meets the dimensional requirements of ASME B18.5 for carriage bolts.