Can ASTM A490 heavy hex structural bolts be fully threaded?

2015 Update: Yes, ASTM A490 bolts can now be fully threaded. There is a supplemental provision in the F3125 specification that allows the bolt to be fully threaded as long as it is stamped with an “S”. The A490 specification starts at ½” diameter and stops at 1-1/2” diameter, and each diameter has its own specific thread length as a standard structural bolt. Structural bolt thread lengths for A490 bolts will be provided unless specified otherwise under the new F3125 specification.

ASTM A490 bolts cannot be fully threaded, and there is not a supplement for a type “T” fully threaded version of the A490 like there is with the A325 bolt. The A490 bolt is equal to the A325 in application and geometry but is much higher strength. Because the A490 bolts are designed to be used in structural applications only, the thread lengths are specified to be shorter in order to keep the threads out of the shear plane joints, as that is frequently the intent of the specification. The A490 specification starts at ½” diameter and stops at 1-1/2” diameter, and each diameter has its own specific thread length with no exceptions, and again that is the intent of the spec. If a customer is looking for a bolt that has the same identical mechanical values but needs a longer thread length or a larger diameter, such as 2”, they should instead consider an A354 Grade BD heavy hex bolt. When moving to A354 Grade BD, magnetic particle testing will need to be specified if it is a requirement of the fastener, since it is not a mandatory test for A354 but is a requirement of A490. A354 Grade BD will have all the identical strengths of the A490 and is much more versatile as far as diameter and thread length.

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