ITP Notebook

Tangrams

April 05, 2021

Intro to Fabrication

5 sets of tangrams 5 sets of wooden tangrams

This week I crafted 5 sets of Tangrams — a geometric “dissection puzzle” made up of various basic shapes that assemble into a square. For each puzzle I also created a frame to hold it.

Preparations

The raw materials The raw materials

I bought my materials (all poplar wood) from Home Depot: Two 5.5” x 0.25” x 24” sheets for the base, two 5.5” x 0.5” x 24” sheets for the tangrams, and six 0.75” x 0.75” x 36” square strips for the frame.

Sketch of the design Sketch of the design

I used the material dimensions to inform the design. The base would be 5.5” x 5.5”, glued to the inner edge of a 0.75” frame — the total size would be 7”.

First Iteration

I started with the frame. I used the miter saw to cut square wood into equal segments. At first I measured the rod each cut — later I used a piece of wood as a buttress helped create much more consistent lengths.

Cutting the frame using the miter saw Cutting the frame using the miter saw

The first frame was a bit misaligned as the edges were not all exactly the same length.

The first frame The first frame

Cutting the shapes

The shapes are arranged in this pattern on the square.

Marking the tangram cuts Marking the tangram cuts

To cut the tangram pieces I created a jig to hold the square — simply a right angle cutout at 45 degrees to the edge.

Creating a jig for the tangrams Creating a jig for the tangrams

I used the jig to cut the square into the Tangram pieces. The wedge allowed my to hold the piece steady as I ran it through the band saw.

The tangram pieces The tangram pieces

Even with the jig, the pieces were still a little mismatched.

The assembled tangrams in the frame The assembled tangrams in the frame

To assemble the frame I clued the edges in pairs, then glued the two pairs to each other and the base.

Glueing the frame Glueing the frame

Glueing the edges to the base Glueing the edges to the base

Making the Rest

Once I had the first prototype I had my process roughly defined. The one major improvement I made was using a guide for the frame cuts, which made the edges much more even.

Repeatably process for cutting the frame Repeatably process for cutting the frame

The remaining frames were much more consistent The remaining frames were much more consistent

Following the same process, I glued the frame edges in pairs.

The pairs of half-frames The pairs of half-frames

I glued the pairs to bases using the corner and quick clamps. Not all of the aligned perfectly — I sanded the edges and bases to make sure the fit was snug.

Glueing the frames Glueing the frames

While the glue dried I cut the remaining pieces.

4 to go 4 to go

The jig came in handy again The jig came in handy again

I then sanded down each piece at an angle to give them a beveled edge.

Sanding the edges with the belt sander Sanding the edges with the belt sander

A closeup of a square piece A closeup of a square piece

The only thing I purposefully made different between the 5 puzzles is the amount I sanded the pieces because I wanted to see how the different versions felt. Some I left pretty straight, others I rounded more.

3 sets with beveled edges 3 sets with beveled edges

The Result

The final result!

5 sets of tangrams

5 sets of tangrams

5 sets of tangrams

5 sets of tangrams

5 sets of tangrams

5 sets of tangrams

5 sets of tangrams