Typical sizes for hex range from 3/8" to 3/4"; #10 to 1/2" for serrated hex; and 1/4" to 1" in diameter for 12 point. Lengths for hex span from about 1" to 5"; 3/8" to 2 1/2" for serrated hex; and 1/2" to 7" for 12 point. Measure length from the underhead flange bearing surface to the threaded end of the bolt.

Hex flange bolts are one-piece head bolts that are flat surfaced. The flange bolts eliminate the need to have a washer since the area under their heads... Hex flange bolts are greatly used in areas that are hard to reach since the flange does the work of a washer in distributing pressure. Depend on grade...

Common grades of A193 bolts and studs used in flange connections include B7, B8 (classes 1 and 2), B8M (classes 1 and 2), and B16.