On 1st March this year LEGO released set 42179: Planet Earth and Moon in Orbit which is a LEGO version of an orrery, a type of mechanical model that depicts the movements of the bodies in our solar system using a complex gear train. While a great way for anyone of any age to learn about the relative motions of celestial objects in space, I wanted to make this scientific set a bit more fictional with the addition of Discworld.
While I’ll explain how I went about doing this we’ll skip to the end to check out the video below showing the final product in motion. My LEGO version of the Great A’Tuin replaces the Earth in the orrery set and spins around happily.
If you’d like to make your own I have made a full parts list and instructions which you can find on Rebrickable. It’s all completely free but if you do make your own I ask that you snap a picture and post it in the “Photos” section of the Rebrickable page.
The instructions are also available – also for free – at the bottom of this article.
Going back to the start of this project and I was inspired by this humorous post where someone replaced the Earth in the set with a circular LEGO plate, making fun of the flat Earth nonsense. The top comment on that post alluded to a Discworld instead of a flat Earth and, after reading that, I knew I had to make it happen.
I started off with designing my own brick-built elephants. I am really proud of these cute little guys which are made with just a handful of pieces, but as soon as I finished them I knew they were still far too large. On its own one of these elephants would be fine, but I would need four of them, a turtle and the world itself, so I had to leave my elephant design in the drafts.
On top of size I was also worried about speed. As you can see in videos of the LEGO orrery, the Earth actually spins rather fast to properly estimate the movement of the planet in the solar system, and any complex builds might tear themselves apart as they spin up.
To scale down I looked at the Earth that came in the set and tried to build my Discworld to be roughly the same size. The Earth in set 42179 is a sphere which has a diameter of five LEGO studs.
A bit stumped at how to make a Discworld this small I remembered that LEGO recently released a new turtle piece just last year. Set 60377: Explorer Diving Boat has an adult turtle in it that is the perfect basis for this build.
This not only cuts down on the total number of pieces the build needs, but should also help everything stay together once it starts spinning.
The turtle piece does have a large downside in the low amount of attachment points. The underside of the piece has four anti-studs while the top has one lone stud to build upon.
I started on the bottom and added a 2X2 round plate with an axle hole in the same bright green colour as the turtle. This is very important as the orrery mechanism needs a solid axle connection to hold onto otherwise it won’t work.
Moving upwards and it’s elephant time again. Here I have to thank javiperillas on Rebrickable. Their smart use of a horn piece as a trunk plus curved tile pieces as ears make for the perfect small representation of an elephant that inspired my build. Their Discworld is still much larger than mine so I had to shrink things down further. Those who make my Discworld may notice that the elephants are actually only half elephants with just two front legs. Their back portions are built into the main shaft of the little build.
If you feel a bit cheated that there isn’t really four full tiny elephants in here, please give building your own Discworld at this scale a try. I’m far from an expert custom builder and I always love to see what others can do.
That main shaft and the connection between the turtle and the rest of Discworld all has to be done on one stud, as mentioned earlier. To add more stability to this, I inserted a 2L bar with stop ring inside of the shaft. This adds a huge amount of rigidity to the entire assembly and I don’t think it would have worked without this single piece gluing everything together. To do my due diligence I really sped up the Discworld on the orrery and spun it around for a few years. Nothing came apart so it is definitely strong enough for display and to show it off to visitors.
Finally the “flat Earth” on top of the elephants was accomplished with a 6X6 round plate in blue. This is bigger than the five studs of the original Earth sphere but it is the only piece that is suitable and, as you can see in the image above, I think it’s close enough. I decorated the top of this with some random tiles in white and blue to simulate continents. It’s not supposed to be Earth or any Terry Pratchet invention on there, just a representation of some world.
Lastly: if anything about this world is insulting to huge Discworld fans I do apologise as I am a newcomer to the series. I hope the build can still be enjoyed as the little novelty it is supposed to be.
