On panels like table tops or blanket chest lids you need some method of keeping them flat. Typically you use some sort of mechanical support like a cleat or a breadboard end. If you want to go the quick and easy route, the cleat is the method for you. It's a strip of wood that you attach to the bottom side of the panel using screws. The cleats have 3 screw holes, with the outer 2 screw holes being elongated to allow the panel to move during the seasonal changes.

In this how-to article I'm going to show you how to help prevent the panel from cupping by installing breadboard ends. If you think about it, a breadboard end is nothing more than a board attached to the end of the panel using joinery such as the mortise and tenon. Once the breadboards are installed I will show you how to install drawbored pins to pull the breadboards in tight against the shoulder of the panel.

It's important to note that although the breadboards will prevent cupping, they should not prevent the panel from expanding and contracting. Doing so may cause the panel to crack. To allow the panel to move, the mortises will be made 1/4" wider than the tenon.