After the proper width is marked on the oversize plank, nails are driven into the resulting pencil marks to  outline the plank edges, and battens are sprung along the nails. If necessary, some nails are pulled and re-positioned until the battens have a fair curve. Then the battens are nailed onto the plywood stack. Afterwards, the planks are rough cut with the band saw, followed by cutting to the exact size using a straight router bit with a bearing that runs along the battens.

Cutting the planks to the right size