Bookmatching is a process that turns a wooden board into two thinner pieces. Once the pieces are sawn in half, they can be opened like a book, revealing two mirror-image planks of wood. There are many different uses for wood that has been bookmatched, though it is especially useful for creating high quality musical instruments.
It is not difficult to cut a piece of lumber so that it is bookmatched. The process involves sawing the wood through the center. The bookmatched pieces are the same length and width as the original piece though each is only half as deep. Opening these two pieces like a book will reveal two pieces of lumber that are symmetrical in the grain.
Bookmatching works best in pieces of lumber that is quarter sawn. This method of cutting involves quartering a log and then sawing the quarters into boards. Though it creates fewer large boards, it improves the grain and the quality of the board. Quarter sawn boards, when bookmatched, reveal a grain that is much more symmetrical when the two pieces are opened. In musical instruments, quarter sawn lumber is ideal because the look of the wood grain is much improved and because the wood ages in a predictable way.
The most apparent reason for bookmatching a piece of wood is that the symmetrical pieces of wood form an aesthetically pleasing mirror image of one another. The grain in the wood and the pattern on it is the same on one side as the other. The technique is commonly used to form two identical sides of a piece of furniture or of a musical instrument.
The predictable aging pattern of bookmatched wood is especially important in the creation of musical instruments. The acoustic properties of many wooden instruments, such as guitars and violins, are dependent on the instrument's shape. Though the instrument is crafted with precision, over time the organic materials that make up the wood can warp due to weather conditions and age. Using lumber that has been bookmatched helps the instrument warp in a symmetrical fashion, which preserves the quality of the instrument.