# Dodecahedral Joint / Connector for 3D Spool Reuse, Dodecahedron

## 3D model description

#### Dodecahedral Joint / Connector for 3D Spool Reuse

With 3D printing, we end up with a lot of spools. As a STEM educator, I have for long wondered how to play with the 3D filament spools before recycling them. Yes, kids might make a big toy car. However, I wanted to build something more mathematically appealing.

Here is a dodecaheral joint or connector, with the right dihedral angle, that can be used to build a huge dodecahedron using 12 spools. Most spools have a flange with a raised edge. So I decided to take advantage of that to design a joint with a groove (8.4 mm wide) that can snap onto the spools and can slide around. The joint curves are designed with respect to a spool with a 100-mm radius.

As shown in in the pictures, it works well. With the empty spools on hand, I was able to make a half-dedecahedron.

#### About the Files and Assembling

1. Joints come in various sizes and groove depths (5_4 means 5.4 mm in edge thickness).
2. Please try a bigger size if you want to move the joint freely around the spool.
3. Joints with a.shallower groove are easier to snap on.
4. To remove a joint, please use a screwdriver to pry it off the spool edge.
5. As the dodecahedron gets big, please ask for some helping hands.
6. Please try ABS filament if more strength is desired; some gorilla glue might also be used.
7. It is helpful to mark off 72 degrees around the spool using a protractor or the figure provided.
8. Please try it out before printing a large number of joints. Obviously, it takes 20 joints to connect 12 spools for a whole dodecahedron.
9. Once connected, the structure is really stable. If necessary, please try using some bolts and nuts.

Have fun!

• 3D model format: STL

## Creator

STEAM educator, learning from and working with K-12 STEAM teachers to explore new ideas of teaching and engagement. I firmly believe ART is at the core of STEM learning or all human learning! I owe my ideas and designs to the hundreds of K-12 children and teachers and university professors I have had the pleasure of working with, in multiple disciplines-- math, science,engineering language arts, social studies, early childhood education and more! All mistakes, of course, are mine! There is no warranty or liability whatsoever implied or explicit behind the designs or ideas. They are all posted for their potential educational values.

When working with children, please strictly observe all safety and health procedures! Please refer to the NSTA safety guides: http://www.nsta.org/safety/.

LGBU Contact: LGBU@SIU.EDU