Building from the Bottom Up
Regardless of which material you make the chair from, the legs and arm supports (pieces 1 to 3) have straight lines that are easily made on a table saw. The front legs have a 12° bevel on their forward edges, and notches with the same interior angle. I made each notch by holding the beveled edge of the leg flat on the table saw top and raising the saw blade to 15/16″, then nibbling the notch clean. This technique forms the proper angle in each notch. To make the rear legs, I traced their shape onto the stock using a template, and then cut the shape out using a sled on the table saw.
To get the 12° angle on the leg’s front ends, I raised the blade on the table saw, held the end square to the blade and slid the saw’s miter gauge up to the leg, adjusting it to the angle of the leg. Then I cranked the saw blade over to 12° and cut the angle onto the rear leg. Repeat the process for the other rear leg.
Now go ahead and cut out the stretchers (pieces 4 and 5). The lower stretcher is simply sticked up; the curved stretcher has a curve cut into its bottom edge. It also has an angled top edge and ends.
Drilling: 1, 2, 3
Once you have completed those machining steps, you can start drilling counterbored holes for your first dry assembly. An important note for those who choose to use this treated lumber: I found it more brittle than non-treated wood, so for that reason I procured a really good quality countersink bit set which came with plug cutters. It cost a goodly sum, but it worked so well that, to me, the cost was worth it. Another thing I did was to use three drill/drivers as I worked: one with the countersink bit to make the counterbore and the clearance hole, the next with the properly sized drill bit for the pilot hole and the third with a Robertson (square-drive) bit. I know that having three cordless drill/drivers might seem a bit overboard, but I have to say it was a sweet deal. The screws I used in this project were stainless steel #7, 1-5⁄8″ with square-drive trim heads.
For each front leg assembly, counterbore and drill your pilot holes, then attach the arm support to the front legs using screws alone — no glue just yet. In the same way, secure the lower stretcher to the front legs in the notches that you nibbled earlier (no glue). The distance between the front legs is 20-3⁄4″. With that done, stand up the subassembly on a flat surface like a workbench or table saw table and grab one of the rear legs. Clamp the rear leg in position, holding it back 7/8″ from the forward edge of the front leg. Counterbore, drill and secure the rear leg to the front leg, then repeat the process for the other rear leg. Now you can test fit the curved stretcher to see if its angles line up properly. When it fits well, secure it as you have with the other parts . With the leg subassembly done, set it aside and move on to the next set of parts.