Carriage Bolts: Also known as “Cup Square”, “Coach Bolts” or “Round Head Square-Neck Bolts”.
Carriage bolt is features a smoothed head which provides a secure fitting by preventing turning from the outer facing side of the bolt.
The square neck grips into the part being fixed (typically wood), preventing the bolt from turning when the nut is tightened.
Used mainly for fastening timber to timber and is extensively used for timber joist construction in house building and numerous decking applications.
Typical uses include security fixings such as locks and hinges, where the bolt can only be removed from the inside.