Recently I decided to experiment a little with the barrel coopering method to create a recipe box that had a curved top. Creating the top would have been possible on the band saw with some thick stock, but I wanted to learn how to do coopering.
You create a curved piece using coopering by taking small narrow pieces of wood and creating a bevel on each side. When you glue each of the narrow pieces of stock together they form a contour. The narrower the pieces that you use, the more defined is the contour. After glue up, and a little planning, scraping and sanding I was able to create a nice smooth curved top to the recipe box that I had designed.
The more difficult part of the process was figuring out what angle to cut the bevel on the short stock pieces that make up the top. The original barrel making cooper’s did this by eye, but I did a little research and with some mathematics was able to generate a set of formulas that could be used to determine the correct bevel angle given the cord length and height of the desired arc, and the number of pieces (otherwise known as “staves”) to be used to make up the arc. By using the formulas you can derive the width and bevel angle for each of the staves.
The recipe box was created using two somewhat contrasting but beautiful types of wood. The top, front, back, and bottom were made from cherry, but the contrasting sides were made from a beautiful piece of padauk wood. If I can find some time I will create a set of plans for the recipe box so that you can make your own. Creating the curved top in this way gives a great sense of accomplishment and makes you appreciate the art of coopering.