Ferguson's Mechanical Paradox Replica

by sawdusty, published

Ferguson's Mechanical Paradox Replica by sawdusty May 24, 2013


In 1750 James Ferguson, a self-educated Scottish astronomer, built what he called a "mechanical paradox". This is an attempt to replicate his design.

An article on the design and it's original maker (pun intended) can be found here.

More from Mechanical Toys

view more

Liked By

view all

Give a Shout Out

If you print this Thing and display it in public proudly give attribution by printing and displaying this tag. Print Thing Tag


I used the description of Ferguson's design and the illustrations from his original text. I did not use the design from 'Digital Machinist' (I could not obtain a copy of that).

There are some other plans available on the Internet to duplicate Ferguson's model. I did not use those either, but I did view pictures of completed versions of those. Google "Mechanical Paradox Orrery" if you want to find more information and images.

BTW, Ferguson's written description included a single gear in the center to drive the three gears at the end, but his later orrery design showed three stacked gears in the center. I used a single gear in this model, I will post the files for the three central gear "stack" later.

I have not yet printed the parts for this, so I don't entirely know whether it will work. My 3D printer is ailing but parts are ordered, so I hope to get back to making stuff soon.

Ferguson also turned his "paradox" design into an "orrery" also correctly called a "tellurion". I hope to do that soon too. Stay tuned.