What's the best way to divide up the parts of this chair for strength and ease of construction?

The design you show is generally laminated and not constructed out of individual solid pieces.

1×2 isn’t 2.5cm x 5 cm. Nominal lumber size is the raw stock size. A 1×2 is actually 3/4” x 1-1/2” (~19 mm x 37 mm).

This material may be too thin for bead lock.

C, E, G & K are going to have grain direction issues. K is especially problematic as there is no grain orientation that will make a strong U-bend. Being at the bottom rear, this will fail the first time someone leans back in the chair.

You might be ok at C and G, but E is also destined to fail. No matter which way the grain in E is oriented at least one side will fail under load.

Build one side and then break it to see where it fails.

-- The hump with the stump and the pump!

If you can make peace with it perhaps breaking on you within a short time, it may be worth going with the divisions you’ve already chosen.

I suggest making a mock up out of 2×4 pine material sawn up to the shapes you need and held together with pocket screws and glue. It can take a lot of design iterations to develop a successful chair and mockups are important to the process in many cases.

Thanks for the replies!

Madmark2: I was planning to find lumber larger than 1×2 and mill it to that size, so I think the Beadlock would work, but as you say, that doesn’t necessarily mean it will be strong enough. I see what you’re saying about K in particular. My design is based on this existing chair, kind of flipped around, but I now see that that chair has a joint right in the middle of the tight U-bend, which seems challenging to replicate at my skill level.

I know lamination and bending is a better way to go, but that’s beyond my capabilities. I had actually originally thought of a laminating in the other direction, though, by routing the profile out of plywood and stacking those. But then I’d have ugly plywood layers, and I wanted to avoid edge banding since I’d like to have a rounded or chamfered edge.

Loren: Thanks for the wise tip about doing a mockup. I’m a fairly inexperienced woodworker, so I like to just jump into things and learn (a lot) as I go, but maple and leather are not cheap, so this could be a costly lesson if it fails.

Hmmmmmm….