Once all of the boards have been rip cut to the pre-sanded width, we then planed them to the desired final thickness. In the middle ages this process would have been done with a hand-plane called a bench plane. Often quite large, bench planes dragged a sharp metal blade across the surface of the wood, slicing off thick curls of wood until the board was the desired thickness. This is a time-consuming process, and Lord Richard and I substituted a modern bench top power planer.
The planing is done at this point for several reasons. First, it relieves the boards of weight. By removing any wood not needed in the final construction now, we make the boards easier to handle in the shop. Second, the planing process goes much more quickly with fewer boards. Third, it is easier to read the layout marks on a smooth board than on a rough one.