Carriage bolts are heavy-duty threaded fasteners with a low-profile, mushroom-shaped head. They originated in the early 19th century. As their name suggests, carriage bolts were initially used on carriages. Carriages — particularly the wheels of carriages — required special fasteners that could withstand heavy usage. This led to the development of the modern-day carriage bolt.

Horse-drawn carriages have since faded in favor of faster and more efficient methods of transportation. Nonetheless, carriage bolts continue to be used in fastening applications.

Carriage bolts are prized for their strength and durability. They are stronger and more durable than most other types of bolts.

You can find carriage bolts in different thread styles. All carriage bolts have threading on the shank. With that said, some carriage bolts have a fully threaded shank, whereas others have a partially threaded shank. A partially threaded shank means that only some of the shank — typically about three-quarters of the shank — is covered in threading.

Carriage bolts can lock into place. Most carriage bolts feature a band directly under the head. As previously mentioned, this band allows them to lock into place. Inserting a carriage bolt into a hole of the same band shape will lock it in place.