Why can’t I find 1/2” diameter A490 bolts?


ASTM F3125 Grades A490 and A325 structural bolts are mass-produced through 1-1/4” diameter. However, there is an exception for 1/2” A490 bolts. Compared to other diameters, these are not commonly used. Therefore, 1/2” diameter A490 bolts are not mass-produced and are not readily available in the marketplace. There are a couple of ways to work around this. First, you could potentially move to a larger diameter that is readily available. However, this will often require the holes in the fabricated steel to be enlarged.  SAE J429 Grade 8 could be considered since they are readily available in ½” diameter and possess virtually identical strength and chemistry.  However, Grade 8 bolts have a standard size hex head (rather than heavy) and longer thread lengths.  Both differences can be issues when working with bolts for structural applications.  Any substitution should be approved by the Engineer of Record.  If neither of these options work, then ½” A490 bolts can be made-to-order from a custom bolt manufacturer such as Portland Bolt. Feel free to contact our experienced sales team and we will happily assist you with your project.

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