KNEX Stressed Tetrahedron
This is a Platonic solid made from standard K'NEX parts. The parts all fit together generally. No hinges or rotating parts were used.
It is named Stressed as the bars must be slightly bent to fit. Remember: wear Safety Glasses when bending plastic. The bends are slight, you only got two eyes. If concerned simply use bendy rods.
This build is simple and is meant to be an introduction to the techniques used in other builds.
Supplies
6 rods 190-mm or larger all the same.
24 16-mm rods.
12 2-connectors angled.
12 5-connectors angled.
(total 54)
Step 1 Making Hubs
Four hubs are made from the parts. Each has 3 2-con , 3 5-con and 6 16-mm rods. It is important to have the same chirality in all the hubs. That is they all go clockwise or anti-clockwise. This is important to keep the model from becoming lopsided.
Step 2 Make a Triangle
With three hubs and three long rods, make a flat triangle.
All the 2-con point up as the inside bottom is up.
Add three rods where possible.
The 2-con should point inward.
The rods will have to be slightly bent to fit. Wear safety glasses.
Step 4 Connect Final Hubs to Finish
Connect the last hub where the rods gather.
When the rods seem to not want to stay, check chirality and connections.
When the model is made with bendy rods, the curves become more pronounced.