square head bolts were much common in industries since they offer minimum chance of wrench slippage while wrenching because of their square designed head.  The square-headed style of these bolts gives them a rustic look which other hexagonal bolts don't have.Square head bolts,Website:http://www.chinajinrui.net, as many other types of bolts, come in stainless steel.  Square head bolts are commonly used in garages to make some shelving. They can easily be fixed in using a wrench. Bolts are used by machine engineers to build or to repair industrial machinery of all kinds and sizes.  In fact, a square-headed bolt can also be fixed in using a pair of pliers instead of a wrench since it provides a good strong grip.