Handmade Wooden Ribcage

Six years ago, when my son took up his university medical studies he exclaimed 'Dad, won't you make me a wooden ribcage for the day i'll finish doctor!?' As one my wildest projects i wanted to document this adventure and share it with you.

Disclaimer: What follows is an artistic interpretation of the human ribcage executed to the best of my woodworking capabilities.

- nature-bent juniper branches

- repurposed Asian wooden pallet

- white glue (PVA) for ribs, epoxy for laminated spine

-assembly adhesive for connecting ribs to spine

-sanding paper for finishing

-linseed oil or varnish for top finish

-various handsaws, knives, chisels and drills

-5 months of spare time after work and weekends

I had subconsciously been mulling over my son's request for quite some time. How do you go about building a ribcage out of wood? You search the internet, of course. After a quick search it was quite obvious this has not been done very much. At least i got no help on how to construct the rib cage, let alone the spine. But an ample supply of rib cage pictures and 3D-representations and rough width-height dimensions boosted my self-confidence. This is doable!

Back to the material. With Finland located in the Nordic hemisphere on same latitudes as Canada our selection of domestic tree species (both soft- and hardwood) is not that broad and predominantly light in wood colour. What i wanted to avoid was a wooden rib cage too much resembling bone colour. I had the feeling my project is no easy task and that's why i want it to stand out - in colour too. Where it was possible. I realised THE single most challenging task was the arch shape of the ribs. Where do i get that? In juniper! Now i have the supply of ribs (front-half of the half-circle), but the colour is what it is. Light. An other limitation was the radius. The juniper branches seemed to strikingly share the same circle radius in their dna but unfortunately the arch was a little too "wide" for my purpose. The implication was that the back-half of the rib arching from the chest bone back to the spine, needed to have an even shorter radius. This was a challenge that also posed the solution. As i needed to resort to man-made ribs as back-halves i could freely chose would species of desirable colour. This is where the repurposed Asian hardwood pallets come in. Redish dark in tone the wood looks great when finished with varnish or oil.

As this project started in winter of January 2021, I did not even bother venturing into the woods browsing tree trunks in search of the slightly s-shape of the spine. No, incidentally my prior project making my first ever half-moon shaped lunette-window was also the springboard of the spine. Scraps of a circular dining table's wooden frame used as window frame was the solution for a gluing jig. I simply finger-joined and glued them into the desired spine shape.

Then i took the dismantled pallet boards and sawed 3-4 mm thick slices with an electric powered circular saw (yes, let the record show the only exception in this hand-tools-only project). I glued the slices with epoxy and clamps in the jig to a sturdy 50x50 mm spine.

I still am pretty pleased with this solution. How do you assemble 10 pairs of ribs when every joint with both chest bone and spine is unique and needs to be handcrafted in place? It occurred to me this reminds me of the tailor working on the upright standing "model". On the pictures the spine is mounted on a stick fixed to a 4-pronged foundation of a discarded office chair. The chest bone is then temporarily mounted to a flexible batten arching from top of the spine and down.

Where the chest bone and spine represent the vertical boundaries of the rib cage, the bottom and top rib pairs sets the horizontal limits. How do i couple the ribs with chest bone and spine? I guess this is where you get to benefit from the plethora of joinery riddles solved under 40 odd years of manual woodworking. The obvious challenge was to rigidly mount the ribs to top and bottom ends of the chest bone. One must bear in mind that the rib cage made is up of twenty unique ribs all independently reaching out in x-y-z spectrum. There is seldom a perfect fit, often some tension in assemblies exerting pressure on joints.This is why i opted for wooden fittings of juniper to join ribs with the chest bone. In the joint between spine and rib i simply applied a dovetail. Speaking of x-y-z you see in the third picture how minor corrections in angles and curves of naturally curved rib components were made.

This pair of ribs has the smallest radius. And thus smallest tolerances when joining the pieces of the arch. Again, the first rib was hardest to muster without cracking. I would say the benefit of 3-layer laminated pallet wood in the back halves of ribs was instrumental. It allowed a solid dovetail in the spine and tightly curving arch.

With upper and lower ribs in place the rest was "legwork". It struck me time and again how similar this felt like building a wooden boat (not that i have done that yet). But first, you see here the 3-layer laminate of sliced (4-5mm) pallet wood. Slices of wood with grain directions intersecting at 90 degrees gives a non-splitting structure suitable for sharp turns and dovetails. The next to last picture is a prototype mortise and tenon joint connecting the juniper (front-half of rib) and the pallet wood laminate. Here PVA glue works fine as it is strong enough and not messy to wipe off with wet cloth.

Final assembly was inarguably exciting. And the curing assembly adhesive i used to secure rib dovetails to the spine added the element of time pressure. Irrevocably no turning back. The mortise tenon joints in front end of ribs and chest bone together with the dovetail joints of the spine made assembly as such fairly easy. The 10 pairs of ribs kept their positions. However when focusing on each rib separately in assembly and so thrilled when all pieces fell in place, i was so close making a capital error. Aligning the chest bone with the spine! Invisible tensions between parts are prone to twist the chest bone in either directions creating a deformed asymmetrical rib cage. Who would want that?

The piedestal may seem trivial but proved a tricky chapter. Decisions to consider like the trade-off between aesthetics and area of the foundation with respect to the stability required to keep the rib cage upright. And creating a design out of wood resonating with rib cage and spine. I settled for a square foundation as it was easy and fairly quick to do. I was running out of time. It was the only logical solution too, as i wanted to cover the pine wood piedestal frame with a more decorative wood species. In hindsight i should have selected the same pallet wood species i used in the spine for colour balance. Next time! Anyway, for increased stability i firstly inserted two 4mm metal plates into the wood frame. The rest was precision carpentry to cover the piedestal in wood of my choice. And top it off with varnish and a silver plate with date and name of the fresh M.D.