Carriage bolts have a smooth rounded head with a square neck underneath that locks into wood when tightened. 

Use with a pre-drilled hole and secure with a hex nut and washer to prevent spinning. 

They are great fasteners for decks, play equipment, docks, fencing, and furniture.

The unique design is great for connections where the head is not accessible for tightening

Made from zinc plated steel for durability

The self-locking square neck and coarse threads fasten very securely

Fully threaded