Frequently Asked Question

Every bolt grade has specific requirements including chemical makeup and strength properties. Virtually every grade of fastener also has diametrical limitations on both the small end and large end of sizes. For many grades the smallest diameter is ¼”, but some start at ½” (like ASTM F3125 and F1554). On the large end most bolts grades end at 4” in diameter, but some end at 1-1/2” (Like ASTM F3125 and SAE J429 [Which includes Grade 5 and Grade 8]). Below is a table of common bolt grades and size ranges allowed under each specification.

What does this mean for the original question? It is not possible to provide bolts outside the size range of any given bolt. You find yourself in a situation similar to ordering a bolt to a steel grade instead of a bolt grade. You could guess on certain requirements, but would have no way of knowing for certain. For most grades that have more finite limitations, there is a similar grade that doesn’t have the same size restrictions.

If you have any questions about available bolt sizes, give one of our helpful team members a call and we’ll be happy to help.

Alternative grades are only suggestions to consider if the requested part is unable to be supplied in the diameter requested. Any substitutions in grade should be approved by the engineer of record for a given project, as unapproved substitutions can open you up to liability concerns.