Hex nuts are six-sided, internally threaded fasteners, mated with bolts, studs, screws, and other externally threaded products. The addition of the hex nut ensures that the bolt etc. Hex nuts of standard thickness are called finished hex nuts. 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. 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. The finished hex nut is perhaps the most commonly used nut in the world today. Found in structural, machinery and automotive applications, hex nuts and heavy hex nuts couple with bolts to create a tight, secure joint. The finished hex nut provides adequate strength for many different types of common applications.