Are there diameter limitations for various fastener specifications?
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.
| Grade | Diameter Range | Potential Alternative Grade(s) for Diameters Outside Range |
|---|---|---|
| A307 | 1/4” – 4” | |
| F1554 Grade 36 | 1/2” – 4” | A307 Grade A |
| SAE J429 Grade 2 | 1/4" – 1-1/2” | A307 Grade A or F1554 Grade 36 |
| F1554 Grade 55 | 1/2” – 4” | |
| F3125 Grade A325 | 1/2" – 1-1/2” | A449 or A354 Grade BC |
| SAE J429 Grade 5 | 1/2" – 1-1/2” | A449 or A354 Grade BC |
| A449 | 1/4” – 3 | A354 Grade BC |
| A354 Grade BC | 1/4" - 4” | A193 Grade B7 |
| A193 Grade B7 | 1/4" – 7” | |
| F1554 Grade 105 | 1/2" – 3” | A354 Grade BC |
| F3125 Grade A490 | 1/2" – 1-1/2” | A354 Grade BD |
| SAE J429 Grade 8 | 1/2" – 1-1/2” | A354 Grade BD |
| A354 Grade BD | 1/4" - 4” | |
| A320 Grade L7 | 1/2" – 2-1/2” |
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.