Can I get Grade 8 heavy hex anchor bolts?

heavy_hex_bolt2It not uncommon for us to get requests or for bolt configurations that don’t match the specifications. Anchor bolts called out as headed Grade 8 bolts are only available with a hex head. From your description ASTM A354 BD would be the correct fastener. This specification has mechanical properties that are very similar to SAE Grade 8 bolts, 150 ksi minimum tensile and 130 ksi minimum yield. A354 BD indicates a hex head unless otherwise specified. So you can work with a manufacturer to meet the requirements of your prints to supply an A354 BD bolt with a heavy hex head. A490 bolts are meant for structural steel connections and have specific thread lengths. For example, a 1” diameter A490 will have 1-3/4” of thread, where as an A354 BD bolt has 2-1/2” of thread or you can specify longer threads as necessary.

Thread Length
The industry standard thread length for fasteners over 6” long is 2 times the diameter plus ½” and twice the diameter plus 1/4″ for anything shorter. Structural bolts, like A490, have special thread lengths that are shorter since they are used in structural connections.

Diameter Range

Here’s a chart that highlights some of the differences between these three specifications.

Specification Diameter Range Min. Tensile Strength Range Min. Yield Strength Range Head Pattern Thread Length
ASTM A354-BD ¼ – 4” 150 ksi, 140 ksi (2-5/8”+) 130 ksi, 115 ksi (2-5/8”+) Hex Head or as specified. 2 X Diameter Plus ½” or as specified.
ASTM A490 ½ – 1-1/2” 150 ksi 130 ksi Heavy Hex Head Specified Per Diameter
SAE Grade 8 ¼ – 1-1/2” 150 ksi 130 ksi Hex Head 2 X Diameter Plus ½”
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