First of all, determine the right size of flag you need to create. Measure the folded flag by getting a tape measure or another flag for comparison. Get the vertical, horizontal and diagonal measurements. You also need to determine the right thickness so you can properly fit it into the flag case.
Next, think of the right type of wood to use. Oak is a great material to work with. You can also go for pinewood which is cheaper.
The flag case is generally rectangular and you can cut the angles at 45 degrees. The length of the board should provide enough allowance so that the flag and glass can easily fit within. Wood also has its own grain so learn how to position the pieces together.
Get the measurements at the longest part of the angle board. Use a speed square or framing square by measuring the board at its long point. Arrange the pieces together.
Also put a short point on the remaining piece. The goal is to turn the piece at 180 degrees. The short point should also be cut again to convert it into a long point.
The coupe of angles at the display case’s top should fit perfectly and the grain pattern must flow well. These should appear continuous when placed together.
Finally, attach the pieces together to create a triangle. The side pieces may appear very long. You can pencil mark at the base so that it goes over the piece. The result flag case will look very symmetrical.