Introduction: Tetris Bookshelf
In honor of the longstanding tetris rivalry between members of the instructables staff, I designed a set of tetris bookshelves for the instructables office using Autodesk AutoCAD and new preview version of Autodesk 123D Make. These shelves are great because they can be rearranged and stacked anyway you like, and you can always make more if you need them. I used a laser cutter to cut the shapes out, making the whole process quick and minimally labor intensive.
Step 1: Modeling in AutoCAD
The tetris shapes are fairly straightforward; each piece is made of four unit pieces arranged in seven different orientations. Since I chose to make my shelves without a back panel, the S and L shaped pieces can be flipped over to produce their mirror images. This means that I only needed to make 5 types of pieces.
I modeled the shelves in AutoCAD by drawing the shapes in 2D, extruding them into 3D and subtracting the inner volumes. The final shelves will be made from 3/4" plywood, with each unit piece measuring 9" inner diameter and 10.5" outer diameter. The depth of the shelves will be 15". For now I've only built a prototype set which has been scaled down by 1/3 and cut from 1/4" plywood. I exported these shapes from AutoCAD as a single stl file to send to 123D Make.
I've attached the dwg and stl files for both the full sized and scaled versions of my tetris shelves.
Step 2: Send to 123D Make
I imported the stl file into 123D Make, a free app that lets you prepare your 3d files for laser cutting. I'm using a new preview version of 123D Make that is not available to the public yet, so I had a lot of control over the type of joints to use for my tetris pieces. The public version of 123D Make will be getting regular updates in the coming moths, so hopefully you will be able to use these features soon too! In the meantime, I have attached my 2D vector files (eps files) for both the mini prototype and full sized tetris pieces.
In 123D Make, I set the joint type to finger joint with 12 fingers for each joint. I specified the dimensions of my material and 123D Make created 2D vector files with the correct finger size and fit them onto sheets for laser cutting.
Step 3: Cut and Assemble Pieces
I sent eps files from 123D Make to a laser cutter and cut them from 1/4" plywood. If you do not have access to a laser cutter or cnc cutter, consider using an online fabrication service.
I removed all the pieces and inspected the edges, some needed additional sanding/finishing. I separated the pieces by size (there are 6 different lengths) and compared them to my 123D Make model. To be safe, I assembled my tetris pieces without glue first.
Step 4: Gluing Pieces Together
I applied wood glue to the joints, assembled the tetris shapes, and clamped them together to dry. For best results, use a corner block to clamp all joints to exactly 90 degrees.
Step 5: Finished Product
Once the wood glue dried I removed the clamps and the five tetris prototypes were done! At this point they could be stained or finished depending on what you like.
More to come when I finish the full sized shelf set...