Hillman 240117 5/16-18X4-1/2 CARR Bolt 5/16 x 4-1/2-Inch

Carriage Bolts are designed to fasten a wooden face to either a wood or metal frame. Its flat head is designed to eliminate the need for a washer and provide a semi-flush finish to applications. The square underside of the head is self locking to eliminate spinning and the need for a driving tool. The zinc plating is rust resistant and provides a beautiful consistent finish; but may not work for all exterior projects. Carriage Bolts have a smooth rounded head that has a small square section underneath. They are used in wood connections utilizing the square neck under the round head which will sit into the hole to prevent the head from turning. These carriage bolts come plated in zinc for moderate corrosion resistance.