S-93548A555 1/4"-20 x 3 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 spinning during installation and use.
• Enhanced corrosion resistance thanks to zinc-plated steel construction, ensuring long-term durability in various industrial environments.
• High tensile strength of 60,000 psi and Grade 2 classification for reliable load-bearing capacity in demanding applications.
• Easy and quick installation with fully threaded UNC coarse pattern and right-hand threading, reducing assembly time and labor costs.
• Wide-rounded head profile distributes clamping force evenly, minimizing surface damage and improving joint integrity.
• Consistent dimensional accuracy with Class 2A thread fit, ensuring precise compatibility and reduced risk of cross-threading.
• Compliance with major industry standards including ASTM A307 and SAE J429, guaranteeing quality and interoperability in professional settings.

Professional Applications & Engineering Value

This zinc-plated steel carriage bolt is engineered to address common challenges in industrial fastening, such as vibration-induced loosening and corrosion. The square neck design integrates seamlessly into wood or metal, providing exceptional anti-rotation without requiring additional locking components. With a Rockwell B70 hardness and Grade 2 strength, it withstands heavy loads and harsh conditions in construction, machinery assembly, and agricultural equipment. The UNC coarse thread and fully threaded body ensure rapid installation and secure grip, reducing maintenance downtime. Ideal for applications where reliability and regulatory compliance are critical, this bolt delivers consistent performance in framing, trailer manufacturing, and structural supports.

Specification Summary & Compliance

This carriage bolt features precise dimensions: 1/4"-20 UNC coarse thread with Class 2A fit for accurate engagement, a length of 3-1/4", and square neck measuring 0.26" width. It conforms to ASTM A307, SAE J429, and ASME B18.5 specifications, ensuring adherence to recognized manufacturing standards. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for global industrial use.