Hex bolts are bolts with a hexagonal head on one end, with no washer face on the bearing surface and a threaded shaft on the other end. Hex bolts are tightened with a wrench and are used to connect metal parts. (The body tolerances of hex bolts are not as close as those of hex cap screws.)

The head of a heavy hex bolt is wider and thicker than that of a hex bolt. A heavy hex bolt goes with a heavy hex nut.