Introduction: 3D Printed Impossible Table
This Impossible Table is a great little 3d printable project to learn the concept of tensegrity and to create a small table that will hold about 1 Kg. This design has two strings holding it up in the middle rather than one, which most triangular designs have. This makes it better because it can hold more weight, and it also has more stability strings on the sides than other designs, so it's more stable. You can also check out this project on Thingiverse for a detailed lesson plan: Thingiverse page.
If you enjoy this project, please vote for it in the Plastics contest at the bottom of this page. I would greatly appreciate it!
3D printer with build volume off at least 110mmx110mmx10mm
Step 1: Printing the Parts for the Impossible Table
First, you need to download the following STL files and 3d print them at 30% infill and 0.2mm layer height. I printed with ABS but other non flexible filaments will work too. The STL's are attached. Print two of the legs and two of the table bases.(Two of each) I designed this fully on Tinkercad, here are the links to my design: Impossible table base and the legs.
Step 2: Assembling the Impossible Table
This step will take about half an hour or more as there are many small knots you have to get tight. Watch this video and it will take you through the assembly step by step. You can also follow these instructions. First, you need to superglue the legs into the notches in the bases, but be careful, because the second leg needs to go through the first like in the picture. Once the glue is dry, you can start tying the strings. Tie the 2 middle strings first, going through the top "leg" holes into the bottom "leg" holes. Make sure the 2 strings are the same length. Then tie 2 (on opposite sides) of the 8 strings from the top base to the bottom base, but turn the top base about an eight so that the strings are on an angle and the legs aren't touching. Then tie the next 2(the quarters) in the same way, still offsetting the top from the bottom by 1 hole. The tie the sixth 2 more across from each other and then the final 2. I used slip knots to tie them and went from the top to the bottom and back to the top, through the loop, and then tied 2 regular knots to keep it there.(The loop in the string that I previously tied was at the top.) Once you have followed the whole process, the table is done. I suggest to watch the video, at least the part where I show how to tie the knots for the legs and for the bases, because it provides a good visual.
Step 3: Testing the Impossible Table
Now that you've built the table, you have to make sure that all of the strings on the sides are tight, and that the top is level. Then you can start putting some small objects on it. Then some heavier ones, but eventually it will break. I was able to get it to hold 1 Kg of PLA filament, but that was with the strings tied perfectly. You are definitely safe to put a pound on it though. Watch this video to see some of the things it can hold.
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