Joining the Halves
With these two completed halves you can get a good picture of what the chair will look like. Set them up side by side with the splay in the front just as you want it to be in the completed chair. You need to do this in order to judge the angles for boring the holes for the front and back rungs. Now lay one of the chair halves flat on the floor with the side to be bored facing up. Set the point of the auger on the post where the rung will go and tilt the auger Cut the rungs to length, shape their tenons, and drive on the other post. over until you have the angle that you want. As you begin to bore this first hole, sight down over the edge of the top knob of the brace and see what point on the post lies directly below that edge. If you have a welldeveloped sense of the vertical, you should be able to duplicate this angle on all of the remaining holes by tilting the brace over until you see this same relative point. Drive in the first rung when you have bored its hole and it will serve as an additional guide in getting the rest of the holes correctly angled.
When all the rungs are set in one side, stand up the two sides together in another mock assembly. Move them about until you have it just the way you want it to be and then mark all the rungs where they must be cut off. Set the two halves back down again, saw the rungs to length, and shape the tenons on their ends. Use mock assemblies to check your angles as you bore all of the holes in the second half. When the holes are done, you can drive the two halves together.
Clamp the bent splats together and plane their bottom edges. To avoid making a chair that has a topheavy look, cut the splats progressively narrower from bottom to top. Before you shape the tops of the splats with their arches or whatever, lay the chair down on its back with the splats underneath their proper places. Scribe down the insides of the two back posts onto the splats to mark how long each needs to be. Shape the tops between these lines and leave enough extra on each end to fit into the posts (5/8 inch or so) before you cut them off. Hold the splat in place to judge the angle needed to match its curvature and start morticing. The chisel should, of course, match the width of the splat, about 1/4 inch. At each end of the mortice cut straight in with the flat side of the chisel against what will be the end walls of the mortice. Alternate these chopping cuts with digging cuts, the bevel of the chisel down, until you reach the depth you need. Resist the temptation to use the chisel as a lever against the ends of the mortice.
With everything morticed, spring in the splats. You can bore some tiny peg holes through the posts and splats to keep them tight. Usually only the top splat needs this; the others are allowed to give in and out.
The rockers are attached with bridle joints, chiseled slots in the bottoms of the posts which fit over the rockers. Secure the rockers with i/4-inch pegs through these joints, but check first to be sure that the chair sits right before you do this. You can adjust the way the chair sits by cutting the slots deeper on the front or back posts.
Test out the chair very carefully. I once had a woman try out a walnut arm rocker that I was making for her. She exceeded the limits of caution, and the chair came off the unpegged rockers, depositing her on her back. Helping her and the chair back into standing position, I laughed and lectured her on the need to be careful when test fitting rockers. Not satisfied with verbally correcting her approach to this delicate procedure, I put the chair back on its rockers, sat down, took one rock back, and immediately pitched over backward myself, hitting my head on the woodstove. She was still laughing when I regained consciousness.
"A Practical Guide to Traditional Woodcraft" By Roy Underhill
© 2012 The University of North Carolina Press