This instructable is less about the actual design of the OCC wooden puzzle (I found out after I started this work that is what they are called, and you can find plans for them on instructables and other places), and more about how I went from seeing this picture of the puzzle to building an initial prototype and then finishing it off to a form that I would be happy to give to someone.
Almost everything we build needs a plan at some point, so I will walk through the process of guessing on the design, adjusting as I go and then evaluating how I would change it in my next build (maybe I will add that at some point when I get there).
All of the work was done with a basic set of table top and hand tools. The picture is of the front corner of my garage/shop.
Step 1: Analyze, Rough Design and Start Fabrication
I saw the original picture on the web (see first pic in previous step) and thought it would be a good exercise to figure out how to build it. I pulled out a ruler and measured on the screen some rough idea of the dimensions. I thought I had some 1/2 inch plywood, so I drew out the design I thought would work.
I ended up finding some 3/8 plywood, so I went with the same design but with that wood. I measured out the planned dimensions and then cut out the three pieces (called A, B and C) on my band saw.
I then marked off the openings with the center marks for drilling them out.
Step 2: Finish Build
I first cut the relief slots, then drilled out the rough openings in each one.
I used the band saw to cleanup the openings on the two pieces that had side slots and then used a small file on all three.
I rounded and smoothed all of the corners and edges on my belt sander then hand sanded them to a finer finish.
Step 3: Prototype Results and Analysis
Since I didn't spend a lot of time calculating out what size each of the slots and openings would be, and my first plan was to use 1/2 inch plywood, it isn't surprising that the fit was much looser than I would have liked. But, you can see from the picture, it still went together well.
Once it was together and in my hand I could see better how the thickness of the plywood and the length and width of the pieces drives how big the slots and openings should be. If I was to try this again I would be able to create a much tighter fit.
That said, after only about 1/2 hour of work I was very pleased. Not wanting to throw out anything that could get some use from, I decided to see how nice I could get the pieces to look.
Step 4: Finish It Off....
Pretty standard finishing steps.
- Sand it down to >200 grit smooth. Blow it off with air gun to get it clean.
- 1-2 primer coats.
- Had some gold paint left from some props work, so a couple of coats of that.
The final end result was pretty enough that I wouldn't be ashamed to give it as a gift. Less than 1 hour of work. It would go faster next time now that I know how it should all fit together.
Now knowing the "logic" of the fit, it would be great to try cutting this out on a laser cutter or CNC router.