Plywood arm/lounge chair made out of birch plywood.

Step 1: Things You Need

Materials:

22mm birch plywood 40x120cm
2x 18mm birch plywood 20x120cm
Wood screws
Dowels
Wood glue
Danish oil

Tools:
I used the following tools, but you can substitute them with whatever you have.

Track saw
Miter saw
Scroll saw
Hand drill
Orbital sander
Hand screw
Clamps
Ruler

Step 2: Design and Cut Material for the Frame

I sketched the design on the plywood until I was happy with the design and then I cut out the bottom side piece part with my track saw and finished the corners with a scroll saw. You can also use jigsaw or bandsaw.

I repeated the same process for the backside as well.

Step 3: Stretchers, Dados and Seat/back Supports

I cut the 18mm plywood into 6 slats - 3 for the backside and 3 for the seat. On the backside piece, I cut out dados with a scroll saw.

For the bottom, I cut a small strip of leftover plywood that spans between the front and back legs and cut dados out on the scroll saw as well. I glued and screw this strip to the side panel.

Step 4: Fill the Holes, Sand and Apply Finish

After driving in a screw to each hole, I cut some dowels, applied wood glue to each hole to attach the plug, and then sand them flush.

Finally, I sanded everything with 180 & 220 grit sandpaper. Since this is plywood, I made sure not to eat through the veneer but I did want to touch over all the surfaces to get them nice and smooth before finishing them with oil. In the end, I applied a coat of Danish oil and wiped away any excess.