Link to Evil Cube Template description. Link to templates. Link to 10th Anniversary Populist post
The Evil Cube template is set up on four sheets of letter size paper, and it will fit on A4. The largest part is almost 11 inches so it still takes a fairly large cereal box to make, and you'll probably need two of those. Of course the first step is to glue the template to your card stock, and when it's dry cut out the parts and all the holes. The grey areas are the glued surfaces. Remember if you're using a box with a glossy surface, sand or otherwise roughen it if it's the side that's getting glued.
The image chamber is the most complicated part to fold and glue. It might be a little longer than your printer area, but they're pointy corners so it should be pretty easy to recreate. Remember to print at 100% and not "fit to print." It should fit pretty comfortably on A4 paper. There are three steps that need to be done in order.
The first is to glue the double layer that makes up the sides of the image chamber. Make sure to tightly crease the fold and in order to clamp it, you may have to fold the remaining end of the flap over your clamps to get the edge well clamped. As always, it's best to get the entire surface adhered.
Next, fold it into the shape of the image chamber. One of the trapezoidal sides is only partially grey. That's where the tripod mount will be glued and that one goes on the inside, the entire grey end is the outside.
The last part, which makes the camera front stiffer and restricts the movement of the film reel, is folded and glued. The front of this structure should be a flat surface - you might have to adjust it a little. The best way I found to clamp it was with a rubber band around it vertically.
The image chamber is then glued to the film holder to create the internal assembly. I forgot to take a picture with it clamped like that but the template is pretty well marked where everything goes.
The stop which holds the bottom of the film reel in place is made from a double layered piece of your cardboard. Note also that the flap at the left isn't glued. You need to open it to get the film reel in and out. It just folds closed and is held there when the assembly is placed in the camera.
To make sure you've got a tight fit, fold the camera back around the internal assembly with the flaps on the inside. In order to prevent them from getting glued together, I always wrap some wax paper around the internal part first.
Then, this time with the flaps on the outside, again separating them with wax paper, fold and glue the front over the back (leave the internal assembly in there so you don't crush the back when you clamp it.)
The winders are my standard 3/8 inch dowels with the end sculpted to fit into the slot of a 120 reel. They're exactly the same as with the 10th Anniversary Populist so I won't repeat it here. With my camera I also glued some cork bottle stoppers to make it a little easier to wind, but that's not really necessary. The tripod mount is also the same other than the shape to fit the image chamber.
Of course, if you're not absolutely sure your card and template is opaque, now is the the time for a few coats of matte black paint. Also remember to cover that edge of the image chamber the film rides over with tape or cloth.
This camera is set up to have a rising front pinhole. The pinholes are taped right onto the front of the internal assembly. The optimal diffraction is just under .3mm by the way. Careful not to cover one with the other. You can, of course, install just one pinhole, but I'd either not cut the second hole in the first place, or cover the hole with tape.
The shutter is exactly the same as with the 10th Anniversary Populist, except it's stretched to cover both pinholes, and the moving shutter itself is cut in half. I liberally cover the surface between the two halves with pencil lead graphite so when you pull the handle for one, friction doesn't pull them both open. It's symmetrical around the horizontal axis so you could mount it for use by whichever hand you prefer. There's no reason why you couldn't make a second pinhole and use this on any of my other 120 cameras.
Because it's important to make sure the film reels get pushed down where that stop will hold them in place, it's helpful to place the camera on it's front when you load the film, place the back over it, and insert the winders.
Film advance requires loosening the supply and then tightening the take-up. Remember to tighten both winders so the film is flat before making an exposure if you want to avoid some unpredictable pinhole fun.
I used beaded pins for viewfinders, I've included some center pinhole finders on the template, but I can't quite think how to make a flat finder for both pinholes except by drawing lines.
Now go out and show everyone how cool you are with your classy cubical medium format camera.