I don’t want to sound discouraging but making a quality hard case from wood could be a major project, depending on the tools and shop space you have and your level of skill and experience! I have a well-equipped 24x62’ shop but would hesitate to build one myself.
One option is to hire this out to an experienced woodworker. We tend to buy hight-quality furniture pieces from a few local shops and even they sometimes order the best from Amish shops out of state.
Note that woodworking can be a quite dangerous process without training and experience. Wood dust can also be hazardous to the lungs without good dust collection and personal protection. I installed a $4000+ dust collection system and still wear a good P100 industrial respirator when working.
The machining and cutting is not difficult with the right equipment but for durability and stability (minimize warping) I’d probably make all joints something other that simple butt joints. This may require at minimum a good shaper or router table and at best advanced joinery such as dovetails, finger joints, or splines/dowels/biscuits (for alignment). Always work with well-dried wood, kiln dried is best to avoid warping aa it dries. Pay good attention to the grain direction and understand that wood naturally changes dimensions with moisture changes. Seal the wood well to prevent it from warping with changes in seasons.
When acquiring wood it’s usually best to buy about 10% more than your design to allow for working around defects and surprises. Be careful of wood with warps - bows, twists, crooks, etc. I generally acquire wood thicker than I need, resaw it to thinner pieces on a big bandsaw, then plane it to thickness and smooth on my drum sander. Note that many boards have internal drying defects and stresses which may be released while processing.
If you want mahogany keep in mind that it is very expensive and some places out to make a buck will sell mahogany lookalikes. I keep on hand a huge supply of true Honduran mahogany, clear, dry, and stable purchased from a long-time friend and trusted wood dealer who stopped by here half way through a 12 hour trip and let me buy what I wanted from a large load - I mostly bought 10-12’ long planks 2-3” thick. What a blessing!
Other cheaper, lighter and still useful woods include but are not limited to eastern red cedar, yellow poplar. Note that the stability of many woods depends on how it is cut from the tree and how it is dried - something hard to judge unless you saw it yourself. (I have a sawmill behind my barn and learned a lot from years of sawing.) Note that MANY nice looking furniture, boxes, and cases are made from highly stable quality plywood faced with beautiful/high quality thing wood such as mahogany veneer. The inside might also be covered with veneer and or cloth or other protective padding.
Line the inside with some kind of soft cloth or padding to protect the finish from the wood and add extra padded pieces to fit the shape and support the accordion, especially the “bend” at the back between the keyboard and the bellows..
Use sturdy hinges, handle, and especially clasps and design it so if the lid pops opens accidentally the top of the box will be against your leg rather than the other way so the accordion doesn’t tumble out into the street.
One way to make a precision box where all sides fit perfectly is to make a completely closed box then separate the top and bottom with a precision saw joint all the way around. This can be tricky. An extra step after separating the halves is to devise some type of seal or short splines to prevent air, dust, and moisture entering from the outside.
I’ve made a number of boxes but never considered an accordion hard case. All my knowledge about accordion cases comes from my own accordion (actually two, one acquired just a few days ago) - both came with hard cases with padding inside to keep the protect and keep the accordion from shifting when transported.
I personally, on the advice of my accordion mentor (I’m a beginner), called Liberty Bellows, discussed my needs with the owner who suggested an excellent padded soft case I think is made from very tough cordura fabric, zipper close, well supported with heavy straps that run completely under and around the case, pad-lockable, with an outside zipper pocket for accessories. I told him the type and size of the accordion and he suggested a model which I’m happy with. It’s also much lighter that the existing hard case. It was much less expensive than purchasing high quality mahogany wood and far quicker than designing, machining, constructing, and finishing a good case! Just MHO!’
JKJ
