Design Curves & Chair Seats
Posted on 15 October 2017
If you build chairs with any curves, it’s difficult to get by without a set of French curves for laying out the seat. In this case, I’m shaping the front of an oddly shaped seat with a traditionally shaped pommel (so ignore the amoeba-like ear edge of the seat).
Begin by marking the centerline of the seat and carry that line down the front edge of your seat. Then, using a combination square, mark the depth of the curves desired for your thighs. At first I tried 5/8”-deep curves on an 1-1/2”-thick seat. They looked too shallow. So I switched to 3/4” and everything clicked. (This is why there are two parallel lines drawn on the front edge).
Laying out the space for the the thighs requires only two points and our largest Design Curve. The first point is where the centerline joins the top edge of the seat. The second point is 6” on either side of the centerline on the horizontal line you drew on the edge.
Show the curve to the two points and rotate it to alter its radius until you have joined the two points and the curve comes to a soft landing on your horizontal line. Repeat this for the other side of the centerline.
I shape this area with a drawknife and a curved-bottom spokeshave. Accurate layout and sharp lines create shadow lines that look crisp.
— Christopher Schwarz