Step 4: Cut the curve
It is possible to cut a gentle curve with an ordinary circular saw as long as the blade isn't too fine.
A general purpose cutting blade will usually do the trick.
This particular curve was cut with an ordinary circular saw.
Obviously, if you happen to have a band saw or some other tool 'purposely' made for the task, then all the better.
Step 5: Drill the seat-top supports
The seat-top supports [e] are made from 145 mm x 45 mm (1 1/2" x 5 1/2") stock.
They are 290 mm (11 5/8") long, angling in 10° at each end. Refer to the picture for visual guidance.
Drill two holes (for the nails) in the middle of each piece, one approximately 25 mm (1") down from the top and one approximately 25 mm (1") up from the bottom.
Make the hole size the same diameter or slightly smaller than the nail.Step 6: Fix the seat-top supports to the brace
On a flat surface, fix the seat-top supports (e) to the brace (b).
At this stage the seat-top supports (e) and the brace (b) are in upside-down position.
Simply nail the seat-top supports (e) to the brace (b) through the pre-drilled holes, ensuring the brace is in the center of the two end pieces (e). See the picture.