S-93548A570 1/4"-20 x 8" 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 under vibration.
• Enhanced corrosion resistance from the zinc-plated steel construction, ensuring long-term reliability in harsh industrial and outdoor environments.
• High tensile strength of 60,000 PSI (Grade 2) provides dependable load-bearing capacity for heavy-duty structural and construction applications.
• Optimized for quick assembly with a coarse UNC thread and Class 2A fit, enabling faster installation and reducing labor time.
• Robust material hardness (Rockwell B70) offers excellent resistance to wear and deformation, extending the fastener's service life.
• Versatile partial threading allows for a secure grip on thicker materials while providing a smooth shank for unthreaded sections.
• Wide, rounded head profile distributes clamping force evenly, minimizing surface damage and improving joint integrity.

Professional Applications & Engineering Value

This zinc-plated steel carriage bolt is engineered to address critical challenges in demanding sectors like construction, industrial machinery, and automotive assembly. The square neck is a key feature that bites into the mounting surface, effectively solving the common problem of bolt rotation during torque application, which is essential for structural stability. The coarse UNC thread (1/4"-20) and Class 2A thread fit ensure reliable engagement even in softer materials or where debris is present, reducing the risk of cross-threading. The zinc plating provides a sacrificial layer that combats rust and corrosion, making it ideal for outdoor frameworks, equipment trailers, and agricultural machinery exposed to the elements. With a partially threaded design and 8-inch length, it offers flexibility for applications requiring a combination of threaded grip and unthreaded shear strength, ensuring a secure, long-lasting fastening solution that withstands dynamic loads and vibrations.

Specification Summary & Compliance

This carriage bolt adheres to precise dimensional standards, including a Class 2A thread fit for consistent assembly and a 1/4"-20 UNC coarse thread. It is manufactured in compliance with ASTM A307, SAE J429, and ASME B18.5 specifications, ensuring interoperability and quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free of restricted hazardous substances and safe for use in various markets.