By: Gary Hall
Lag bolts are heavy wood screws with square or hexagonal heads that are driven in by a wrench. They are essentially fasteners made of metal and can be rotated in or out a surface with pliers. Lag bolts are normally used with washers so that their heads do not get stuck into the wood when screwed into a slot. These bolts are primarily used to fasten large heavy timbers such as beams on posts. They can also be used in railway trestles and bridges, as long as timbers are used.
The masonry also uses lag bolts heavily. The thread of a lag bolt mixes with the metal lag for a more secure fastening, hence its name. Because these bolts are known to support very heavy loa