An Introduction To Coach Bolts And Coach Screws - What's The Difference? (Video)
In the video below, we discuss the difference between coach bolts and coach screws and explain how they are used.
What are Coach Bolts and Coach Screws?
Coach Bolts and Coach Screws are fixings that are primarily used in construction and timber trades. They are mostly used when working with heavy timber.
What is a Coach Bolt?
Coach Bolts can also be referred to as Carriage Bolts – this is because they were once used to fix metal straps to the wooden exterior of horse-drawn carriages! Nowadays, Coach Bolts can be used for a range of applications.
Coach Bolts feature a round head and a square underside. They’re generally used for drilling into wood and can join timber to both timber and metal. Coach Bolts are particularly useful when joining segments together at critical points within a structure, as they’re very sturdy and robust. They also have an unthreaded section below the head, which makes them more resistant to force than other fully threaded fixings.
Our Coach Bolts are available in multiple thread diameters (M6, M8, M10, M12) and finishes (Bright Zinc Plated Steel, Self Colour Steel, Galvanised Steel, A2 Stainless Steel & A4 Stainless Steel), as well as ranging in length from 25mm to 240mm. Our Coach Bolts also come paired with matching Nuts for easy installation.
What is a Coach Screw?
Coach Screws, while similar, should not be confused with Coach Bolts. Coach Screws are heavy-duty wood screws that can screw straight into timber. They feature a hexagon head and are mainly used when fastening heavy wood into place, for example when installing fences or gates.
When installing a Coach Screw, you should make sure that you always drill a pilot hole, as you run the risk of splitting the wood without a pilot hole. The size of the pilot hole can vary depending on the type of wood you are using. For hardwoods such as oak or mahogany, the pilot hole should be ¾ the size of the screw diameter; for softwoods like pine or cedar, the pilot hole should be ½ the size of the screw diameter. As an example, when installing an 8mm Coach Screw, you should drill a 6mm pilot hole in hardwood and a 4mm pilot hole in softwood.
When working with Coach Screws and timber, we advise using a flat washer or square plate washer to avoid unintentionally countersinking the head of the screw into the wood. For use with masonry, we recommend using a plastic plug to install your Coach Screws.
Our Coach Screws are available in multiple thread diameters (M6, M8, M10, M12) and finishes (Bright Zinc Plated Steel and A2 Stainless Steel). They range in length from 50mm to 150mm.