3D printed rim Joiner

 

Setup of joiner for cube - see line 2 of diagram below

Cube (table without tabletop) with one side missing. This is sturdy enough but it rocks a bit. Any bigger and it wouldn't fit through the door!

I thought this would be ok but it was a bit flimsy

Tetrahedron with now very rusty steel joiners

New joiners with internal washer spacers set up for cubes.

Joiner schematic

After making the icosahedron sculpture and having difficulty making the joiners without sharp edges, I decided to have a go at something else, and came up with a design for a 3d printed part that would do the same thing. It could have lots of advantages compared to the processed steel parts I had been making and using:

* Able to make one part that's versatile for different platonic solids and prisms without extra effort

* Should be rustproof.

* Made from strong PLA+ material

* No need for deburring as 3d printing with a 0.6 nozzle

However on the other side, 

* May not be as strong as steel, so care needs to be taken with assembly.

 So I've started on a cube, I aim to build the icosahedron cubby house next, wish me luck!

2024 Icosahedron

 

Icosahedron at its current site

On the road

Et voila

Next step

Work in progress

Building in front yard

Drilling jig, drilled joiner, and painted joiner the single thru bolt.

Deburring inside using lathe

Dodecahedron made with the same techniques

Bringing home the wheels

Dumpster at a local environment park's bikeshed

Late last year I attempted to make an icosahedron sculpture from old bike wheels and failed but was not put off! I had tried to make joiners from cheap, weak wood, and also did not bother despokifying the wheels I was using. All this combined to make the thing collapse under its own weight.

So this year, when I was ordering some cut steel tube for shelving, I also ordered some tubes for icosahedron building. As well as getting the steel cut, the parts had to be drilled, but were also deburred, degreased, dried, primed and painted. The drilling was at the dihedral angle for the icosahedron of 138.2 degrees, and I 3d printed a jig that let me mark out and then drill the holes. Quite early on I realised a shortcut was possible and used a single bolt (instead of 2) in each of the 30 joins between rims.

When all the parts were ready including wheels with spokes removed, I started in, and managed to build an icosahedron in my front yard before Christmas (complete with lights and dangly things and windmill) . Then I transferred it to M's house in time for Christmas lunch. For short distances it can be busted into 3 rings of 5 with 5 loose wheels, and the rings fit (rather conspicuously) on the top of my small car. Not great for longer distances though!

With this success under my belt, I changed the icosahedron into a smaller "glamping" hut which seems to be quite good and could be slept in.  My grandkids were amused by the structure, but the general consensus was that the joiners were still too sharp for kids to play with it as a cubby house. It was back to the drawing board again but this time it wouldn't take a year!  I've been gathering bike wheels again, and a new design is almost ready! More in next post.