CARRIAGE BOLT (ROUND HEAD SQUARE NECK BOLT, COACH BOLT)

A carriage bolt has a square shoulder under a rounded head which resists turning when the nut is tightened or removed. They are good for wood-to-wood connections when the head may not be accessible for tightening. They may be used in the construction of docks, swing sets and decks as well as other surfaces where a smooth finish is needed.