Our chair seats are always made of seven parts, doweled and glued together. When we are laying out the parts for chairs on the lumber, we select a board or portion of a board that will make eight, or more, of these seat parts.
Making the seats of seven relatively narrow parts makes them more stable. Laminations, done correctly, are always more stable than a section of wood as it came from the tree, because the growth rings, and therefore the tensions, are crisscrossing and counteracting. To further advantage, this width of seat part allows us to cut the contours of the seat scoop in manageable sections at the bandsaw.
Selecting the parts from one larger board ensures that the color, texture and figure are integral across the seat. Cutting eight seat parts to choose seven greatly improves the composition of figure in our chairs by providing many more possibilities for order. The possible permutations of seven things taken seven at a time are 5040. The possible permutations of eight things taken seven at a time are 40,320.
At each joint, we spread an even and full layer of glue and drive in four dowel pins for alignment. When all the joints have glue and dowels we clamp them tight and leave them overnight.
