S-93548A556 1/4"-20 x 3 1/2" ASTM A307, SAE J429, ASME B18.5 Carriage Bolts

Key Features & Benefits at a Glance

• Superior corrosion resistance with zinc-plated steel construction, extending service life in harsh environments
• Enhanced anti-rotation performance due to integrated square neck design that prevents spinning during installation
• High tensile strength of 60,000 PSI ensures reliable load-bearing capacity for demanding applications
• Excellent durability with Rockwell B70 hardness, providing resistance to wear and deformation
• Wide rounded head profile distributes clamping force evenly and reduces surface damage
• Coarse UNC threading enables quick assembly and superior grip in various materials
• Full threading along the 3-1/2" length offers versatile fastening depth and adjustment flexibility

Professional Applications & Engineering Value

This Grade 2 zinc-plated steel carriage bolt is engineered to address common industrial fastening challenges, such as loosening under vibration and corrosion in outdoor settings. The square neck securely locks into materials, eliminating rotation during nut tightening—ideal for wood-to-metal connections in construction, agricultural machinery, and trailer assemblies. The zinc plating provides a protective barrier against moisture and chemicals, while the coarse UNC 1/4"-20 thread ensures easy installation in soft materials without stripping. With a 60,000 PSI tensile strength and Rockwell B70 hardness, it delivers consistent performance in heavy-duty applications where reliability is critical, reducing maintenance needs and downtime.

Specification Summary & Compliance

This carriage bolt features precise Class 2A thread fit and UNC coarse threading for standardized compatibility. It meets ASTM A307, SAE J429, and ASME B18.5 manufacturing specifications, ensuring dimensional accuracy and mechanical properties. The product is fully RoHS 3 (2015/863/EU) Compliant, supporting environmental and safety regulations in industrial supply chains.