When I saw the possibilities of wood joints with the CNC I got very excited, mainly because I've always wanted to built a piece of furniture but I've never had access to either the knowledge, tools or materials.
My original idea was to build some sort of 'smart furniture'; a piece of furniture with some sort of tech aspect to it like a wireless charging pad or bluetooth connectivity. However, I had never built anything like this so I decided to focus on making a traditional night stand as a first attempt and to familiarize myself with all the intricacies of this process.
Note: the skill builder is contained in this blog post since I prototyped all the joins I used.
Process
There is a step on my bedside that needs some sort of short table. Every day when I get home I see that space and tell myself that I need to either buy something of build something for it.
I wanted some sort of table with double storage. A top surface for immediate things and a second and more secluded section for secondary things like books.
In order to understand the size of the surface I needed, I drew the surface on a piece of paper and placed a few objects on it. To get the height of the night stand, I grabbed a big ruler and measured from the floor to where I wanted it to go in regards to my own leg.
Once I had the rough dimensions, I researched online to see examples and other CNC furniture out there. I found some great resources like opendesk.com and some very interesting Instagram hashtags like #woodjoints.
After having a rough idea of what I wanted to design and build, I started playing with cardboard to learn how things fit together.
This helped me a lot to understand the design requirements in order to make something fit together.
I started designing the night stand with the idea of making it in a way that no glue was needed in order to fit it all together. I wanted the thing to be like a structural puzzle that holds itself together. I started drafting the idea on paper and pencil and modeled in SketchUp after that so that I could see how it all comes together.
As you can see, there are four parts in total. A top, a middle and two legs. The middle and legs come together by inserting and pushing down on the middle part, and the top part gives a second line point for the structure to be held straight together.
I wasn't sure if this made sense, so I tested the joints by cutting a sample piece that contained all the joints and 3 different sizes of bucks in order to test for the right offset. Additionally, I wanted to visualize the impact of not using dog bones in squared joints.
I learned that dog bones help get a much tighter and flush fit, so I included them in the final design.
Once I had the right measurements, I came back to the sketchbook and adjusted for the offsets. I left the the legs fixed and adjusted the top and middle offsets. After that, I ported everything to VectorWorks and added radiuses and dog bones. I am happy to say that I'm much more confortable with it now, but I need to learn about the 3D modeling capabilities.
CAM time came after that. The cuts are fairly simple so this step was pretty straightforward. I split the CNC cuts in four different files, all positioned relative to the same origin in order for me to not have to recalibrate the origin after each cut and also to be able to resume a job if something wrong happened.
Once everything was ready, I cut down my 5x5 piece of Baltic Birch to 4x4 in order to fit on the CNC.
I fixed the board with a lot of screws to ensure that I had a flat surface and no warping was being introduced. I might've exaggerated here, but I wanted to ensure that there weren't any problems while cutting, and it worked. After that, the usual router setup continued and nervously pressed start.
I started cutting the top part and approximately halfway through I realize that I told CAM to cut the outer cutout first instead of the inner ones. I paused the process, went back to CAM, changed the order of the toolpaths and returned to the CNC. The job was resumed with no issues at all.
After the top part came, I reinforced the screws to compensate for the voided force due to the lack of material holding everything down.
Continued cutting everything and the pieces came out perfectly one after the other. I preliminarily tested that everything fitted before continuing with the next file.
Pretty happy with the results, I sanded everything with a 220 grade paper. Got some splinters during the process but the wood turned out pretty soft.
The assembled piece looks pretty great to me.
Final Notes
There is some wobble due to the top part having a bit more offset that I needed. I designed another part but due to the shop's vacuum being broken, other classmates waiting for their turn and me having slept 1 hour the day before, I decided to cut the part after turning in the assignment.
Nonetheless, we can enjoy some nice pictures of it. All assembled without glue or screws..
You'll notices a few paper wedges I had to add in order for it to be firm. This fixes the wobble, so I'm confident that cutting the new piece with more precise offsets will fix it permanently.
