Carriage bolts are a common type of fastener that are used to attach two pieces of material together. They are commonly used in woodworking and construction projects, as well as in automotive and marine applications. In this article, we will explore what a carriage bolt is, how it works, and where it is used.
What is a carriage bolt?
A carriage bolt, also known as a coach bolt, is a type of fastener that is designed to be used with a nut and washer. It has a domed head and a square or ribbed neck, which prevents the bolt from turning when tightened.
Types of carriage bolts
Carriage bolts are available in various types, including standard carriage bolts, plow bolts, timber bolts, and elevator bolts. Standard carriage bolts are the most commonly used type, with a smooth, dome-shaped head and a square neck. Plow bolts have a flat head and a square neck and are often used in applications that require greater bearing strength. Timber bolts, also known as mushroom head bolts, have a rounded head and are typically used in the construction of wooden structures. Elevator bolts, with a flat, countersunk head and a square neck, are used in the construction of elevators and conveyor systems.
Who invented the carriage bolt?
Micah Rugg, a blacksmith from Connecticut, is credited with inventing the carriage bolt in 1818. He realized that conventional fasteners were difficult to install and remove from the underside of a carriage or wagon, so he designed a bolt with a square neck that could be easily tightened with a wrench while preventing the bolt from rotating.
When was the carriage bolt invented?
The carriage bolt was invented in the 19th century, although the exact date and inventor are unknown.
Why is it called a carriage bolt?
The name “carriage bolt” comes from its historical use in the construction of carriages and wagons. The square neck under the head of the bolt was designed to prevent the bolt from turning while the nut was being tightened, making it easier to assemble the carriage or wagon.
How do carriage bolts work?
Carriage bolts work by being inserted through a pre-drilled hole in the material to be fastened, with the head of the bolt on one side and the nut and washer on the other. The square or ribbed neck of the bolt prevents it from turning when the nut is tightened, ensuring a secure connection.
Where are carriage bolts used?
Carriage bolts are used in a variety of applications, including woodworking, construction, automotive, and marine. They are commonly used to attach wood to metal, such as in building decks and outdoor furniture.
What size carriage bolt to use?
The size of carriage bolt to use depends on the size of the material being fastened. It is important to choose a bolt that is long enough to go through both materials and still have enough thread left over to attach the nut and washer.
How long should a carriage bolt be?
The length of a carriage bolt should be at least twice the thickness of the material being fastened. For example, if you are fastening two pieces of wood together that are 1 inch thick, the bolt should be at least 2 inches long.
Are carriage bolts strong?
Carriage bolts are generally considered to be strong and durable fasteners, especially when used with a nut and washer. However, their strength can vary depending on the material they are made from and their grade.
What grade are carriage bolts?
Carriage bolts are available in a range of grades, with higher grades being stronger and more durable. The most common grades for carriage bolts are 2, 5, and 8, with grade 8 being the strongest.