Which plugs go best with coach screws?

While often mistaken for nut-fastened coach bolts, coach screws are heavy-duty heroes in the world of woodworking. These hexagonal-headed screws, easily identified by their hex drive, are the go-to choice for securing heavy timber structures like gates, fences, and sturdy furniture. Check out our article to find out various applications of coach screws.

When to Use Plugs with Coach Screws?

While coach screws excel in wood-to-wood connections, some situations require additional support, and that's where plugs come into play. Here are the scenarios where using plugs with coach screws is recommended:

Attaching wood to masonry (brick, concrete, etc.):
Masonry materials are too hard for the coach screw threads to grip effectively. In such cases, a nylon wall plug expands as you tighten the screw, creating a secure anchor within the masonry and enabling the screw to hold the wood firmly.
Securing wood to hollow walls (like stud walls):
The soft material behind the wall surface cannot provide enough support for the screw alone. Using a cavity fixing plug along with the screw fills the hollow space and offers additional grip, preventing the screw from pulling out.

Here's how they work:

Drilling the Hole: The first step involves drilling a hole in the masonry slightly larger than the screw diameter (typically 2mm wider).
Inserting the Plug: The chosen nylon wall plug is then inserted snugly into the drilled hole.
Driving the Coach Screw: The coach screw is driven through the timber and into the pre-inserted plug. As the screw tightens, the nylon expands within the masonry, creating a secure anchor that holds the wood firmly in place.

Best Plugs for Coach Screws:

The type of plug you choose depends on the material you're attaching the wood to:

For masonry applications: Nylon wall plugs are the best choice. Select a plug with a diameter 2mm larger than the coach screw size for a snug fit. For example, a 10mm coach screw requires a 12mm nylon wall plug.
For hollow walls: Cavity fixings are specifically designed for such applications. Choose a cavity fixing with a size and weight rating suitable for the coach screw and the intended load.

Remember: While this guide provides a general overview, for complex projects or when unsure about specific materials or applications, consulting a qualified professional is always recommended. They can offer expert advice and ensure your project is completed safely and securely.