Rungs, Splats, and Rockers
Make the parts that need to be driest—the rungs—first. Split them from a block of straight-grained wood that is as long as the longest rung—about fifteen inches on my chair. Woven-seat chairs use two kinds of rungs: the regular round ones and the four odd ones that frame the seat weaving. These four seat rungs are wing shaped in crosssection to enable them to support you without breaking. When you have split out the blanks for all these rungs, rough them down with a drawknife to about 20 percent larger than their finished size (5/8 inch in diameter on my chair) and put them aside to dry. The final shaping and smoothing can be done only when you're sure that the shrinkage of these pieces is complete.
When the rungs are put away, begin splitting out the back splats. The splats on my chair are about 12 1/2 inches long and 1/4 inch thick; I rive them out of green wood, just as I would roof shingles. Most woods for chairs, like oak and walnut, want to split radially rather than tangentially: that is, across the growth rings, like the spokes of a wheel, rather than with the rings. The best way to find out how the wood you are working with will split is, again, to experiment. You should try to divide the wood exactly in half each time. Don't try to split a piece into thirds, because you must put the same bending stress on both halves of the piece being split. If one of the halves is thinner and is bent more than the other, the fibers on that half will be stressed and weakened more than those on the other and the split will run out that way. You can control the direction of the split to some extent by putting extra stress on the thick side by bending it more than usual.
The splats for the back must be curved. Take the riven-out splats and shave them thin and smooth so that they will bend evenly. If they are still green, you can bend them as they are and they will hold the set. Drier stock will need to be steamed for about an hour. Bend the splats by weaving them between three poles, as you used to do with popsicle sticks. Pieces this thin will be set in a few days, but a week is best.
If your chair is to have rockers, rive the pieces for them out of the same straight stock used for the splats. As long as the wood is split out and not sawed, the rockers can be as thin as 3/8 inch and still be plenty strong; however, rockers that thin may be hard on rugs. Trace the pattern of one of the rockers of your copy chair onto the blanks. The outside, or convex, curve is easily cut to the line with the axe; the inside, however, will need a single saw or axe cut to the bottom of the curve so that a split started at one end won't run out through the rocker at the other end. Cut down from the ends into the middle of the rocker with a double-beveled hand axe to within 1/8 inch of the line. When both are roughed out, clamp them together and shave them as one with the spokeshave. Put them away to dry.
"A Practical Guide to Traditional Woodcraft" By Roy Underhill
© 2012 The University of North Carolina Press