You will need these materials for each chair:
Approx. 14' of 2" x 4" or similar
Enough 3/4" material to make two planes, approx. 18" x 16" each -- I used maple flooring, but you could use plywood or other material
16 #10 x 3-1/2" galvanized wood screws
Tung oil or finish of your choice
You will need these tools:
Bandsaw, jigsaw, or circular saw
Random orbital sander
Assorted bar clamps
Step 1: Cutting the Frame
The legs are all 24" long; to ensure they all hit the ground evenly, and your chair doesn't rock, set up a stop on your chop saw. Clamp a block 24" from the blade, as shown, then butt your workpiece against the block and chop. This makes all the pieces exactly the same.
Next, lay out the angles for the legs. The back of these chairs is too upright -- the next version will be more laid-back for comfort. I would recommend cutting the back at a more extreme angle, perhaps by using 2" x 6" material for the back legs. The angles are really up to you -- I tapered from 3-1/2" at the top to 2-1/2" at the bottom for the front legs.
To mirror that taper on the back legs, maintaining visual balance, measure 1-1/2" in from the long edge of the board at each end. Then run a straightedge from your mark to the opposite corner and strike a line. Repeat for the second mark. You will now have two opposing tapers, intersecting at 12". The intersection will be the top of the seating surface.
Mark a line at 14" from the bottom on the front leg -- this will be the top of the seating surface in the front. A fall of 2" will provide a nice, deep recline, and 14" off the ground is a low-slung, loungy seating height. Cut all the tapers with a bandsaw, jigsaw, or circular saw. Run a belt sander over the cuts to smooth out any ripples from the cut.
The horizontals are also 2" x 4"s, ripped down to 2-1/2" wide on a table saw. The seat horizontal is about 17", and the arm horizontal about an inch longer. Lay them out on top of the legs and trace notches out, giving the horizontals at least a 3/4" seat. Cut the notches with a bandsaw or a jigsaw, making sure to cut a little small for a tight fit.