Lag Bolts/Lag Screws
Known as lag bolts or lag screws or coach screws, these are among the toughest fasteners used in the industry. These extremely sturdy fasteners are usually used to connect heavy lumber or other heavy materials that bearing intensive loads. Their distinctive feature is their huge size with their starting size being approx. 20mm long and about 6mm thick. Lag screws have sharp lead thread points and are usually hex head.
Pilot hole – it is good practice to make trials to establish the optimum hole diameter in wood so that the body does not split while tightening.
Using a washer is recommended when fixing on wood or other softer materials.