Assembly - One Half at a Time
When you're ready to put it all together, the rungs, splats, and rockers should all be dry, the four posts still somewhat green. Assemble the two sides of the chair first, then join these two halves with the seat splayed out in the front as it should be, spring in the splats, and put on the rockers.
Bring all your rungs down to their finished size. A small hollowbottomed plane will give you an excellent finish on the dry wood, but you can do quite well with simply a drawknife and shave. You may wish to have the rungs slightly larger in their midsections than on the ends. Shape a slightly oversized tenon to fit a 5/8-inch-diameter hole on one end of each of the rungs with the drawknife. With experience, you can do this by eye, but you may want to bore a hole in a piece of scrap to use for a guide in the beginning. Be sure to make them somewhat oval so that the stress will be exerted along the grain of the posts. A slight undercutting all the way around the tenon about 1/2 inch back from its end will add much to the strength of the seasoned joints. Remember that the wood of the unseasoned posts is going to shrink up across the grain (horizontal) and not along it (vertical). You must cut the tenon on the rung large enough so that the hole in the post will shrink up tight around it, but not so tight that you crack the post open. Experience alone will teach.
Lay the posts beside one another and scribe the lines where the rungs will be set in. The front and back wing-shaped seat rungs are set in just below the two side seat rungs. This, of course, makes the seat fit your bottom better and keeps your legs from going to sleep.
With a brace and bit start boring the holes for the side rungs in one of the posts. To judge the depth, count the number of turns of the brace that it takes to get to where you want, which is about threequarters of the way through the post. Stop every five or so turns after shavings appear and see how deep the hole is. The total number of turns that it takes to bring the hole to the right depth will be the number of turns to use on each of the other holes.
Once the first hole is bored, go ahead and drive in the finished tenon of the rung. The wing-shaped seat rung goes in with the trailing edge to the inside of the seat. Having one of the rungs in place will assist you in aligning the next one. Eyeball the brace and bit as you drill to make sure you are lined up with the rung you just put in.
Now you have a post with several rungs sticking out of it. Bore the other post for that side, cut the rungs to length (12 1/2 inches long on my chair), prepare their tenons, and drive it together. You now have either a right- or a left-hand chair half. Go ahead and put together the other half, making sure that the wing shape of the seat rung trails to what will be the inside of the chair. Another view of the ball and socket.
"A Practical Guide to Traditional Woodcraft" By Roy Underhill
© 2012 The University of North Carolina Press