What visual markings does a grade 8 piece of all thread rod have that would identify it as being so? Meaning, how can you tell just by looking at a stick that it's grade 8?
Most grade 8 bolts require a permanent marking symbol that is designated by 6 radial lines. However, the SAE J429 specification that covers grade 8 fasteners does not require grade markings for studs (fully threaded rods) or slotted and cross recess head products. Therefore, you will not be able to visually identify a threaded stud that is certified to an SAE specification.
On the other hand, ASTM specifications require studs to be marked on one end with a grade symbol and manufacturer’s identification. Our Fastener Identification Markings chart will help to identify various SAE and ASTM grade markings. For more information, see our FAQ on the differences between SAE and ASTM graded fasteners.