Carriage Bolts, also known as Coach Bolts & Screws, have a domed head and a short square section under the head witch is designed to fit into a square hole into the material being fastened. These coarse thread carriage bolts are available in sizes ranging from 10-24 x ¾  to  ¾-10 x 24, and come in carriage bolts are available in low carbon zinc plate, hot dip galvanized, Grade 5 zinc, grade 5 plain, grade 8 plain and stainless steel. Carriage bolts meet ASME B18.5 specs.