Carriage bolts, also known as round head square neck bolts, are used in timber structures together with a nut and washer where you need an installation without a protruding head. The bolt has an undersize thread (6az) before hot-dip galvanization and is only compatible with nuts that have normal thread tolerance (6H).

The Carriage bolt is bright zinc plated for use indoors, and hot dip galvanized for use outdoors. The Carriage bolt is made of steel grade 4.6.

Install in pre-drilled holes that are slightly larger than the bolt diameter. Knock in the Carriage bolt so that the square neck sinks into the timer. Now fit the nut and washer and tighten to a suitable torque. As the Carriage bolt is designed for installation in wood there are no details concerning tightening torque.