Coach Bolts.

What is a Coach Bolt?

Also known as carriage bolts, or round head square neck bolt. Coach bolts normally have a large mushroom, or hexagonal head, with a square under the head. Coach Bolts requires a wrench, spanner or pliers to turn. They have a threaded cylindrical shaft and the threads bite into the wood when used with timber. They are mostly in made in mild steel but high tensile ones are available.