Conversation Orbits

By Alexandra Schaefers

orrery 012Jim Donnelly was the classic mechanically inclined kid that grew up immersed in LEGO, Meccano (think Erector set), and model rockets. “I don’t remember not being involved with toys that you could build stuff with,” Donnelly said before recounting a story his father tells about the day he left a three-year-old Jim alone with a disassembled lamp for a moment and returned to find the lamp completely reassembled and fortunately unplugged.

Now Donnelly has his own machine shop where he makes scientific demonstration instruments. His main products are orreries that model the orbits of the sun, moon, and earth in relation to each other—accurate enough to “illustrate the counter-rotating motions of the moon’s nodes and the apogee of its orbit,” a lever paradox that appears to defy physics, and Napier’s bones─numbered bars used to figure multiplication, division, and root extraction. All of his projects are finely crafted and have an antique look of the era in which they were invented. His shop brims with shiny gears and globes, delicately engraved plates, all tiny in comparison to his industrial machining equipment.

Donnelly’s shop was a long time in coming. For his college education, he chose to study broadcasting at OSU. In his senior year he realized how important PCs were going to become at about the same time a network executive told him it wasn’t possible to make any money in broadcasting if you wanted to do programs for anyone with more than a fourth grade education. He quickly incorporated computers into his education, and upon graduating began his current career as a software engineer.

While earning a degree and beginning his career, Donnelly never stopped thinking about making scientific instruments. His interest started in childhood after seeing all types of scientific instrumentation in physics labs around the world with his father, a physicist, who he joined on a family trip to a science museum in London.

Donnelly became further focused on scientific demonstration apparatus while he ran a planetarium at SWOMSI (now called the Science Factory) in Eugene. “That was fun,” he said of his volunteer position there, “and in fact, the people on that job introduced me to my wife.”

This was not incidental. The lack of a shop was the only thing keeping Jim from beginning his craft.

“The key to getting a shop is to marry the right woman.” he said. “[We] were house hunting and she saw me see the shop and knew it was over before I did. I had doubts about whether buying this place was a good idea, but she essentially read me the riot act and said, ‘you know, you have a dream to have a shop like this you need to seize it…’ and here we are—she gets the house, I get the shop and I’m happy.”

Of course, Donnelly had almost nothing to put in his shop when they first moved in, but his wife again saved the day by joining Albany Civic Theater. Jim got involved with crafting the sets and props and his shop evolved because every new project for the theater involved a tool he didn’t have.

“The joke in the theater for a couple years was that I wouldn’t take a project unless it involved a tool I didn’t have,” said Donnelly.

Donnelly eventually had to start his own projects to build his shop and skills up to make demonstration apparatus. He began making model engines that run on compressed air, following instructions in articles engineers publish in specialty magazines.

His requirements for picking engines where: “A. that it would look cool and B. that it would have a part that I wouldn’t have a clue how to make. A few years of that and I learned quite a bit.”


Donnelly started making his first orrery in 2004, inspired in part by Ian Coot who was building one in England and posting his process online. Jim finished his first two at 2:30 in the morning on Christmas day in 2008, just in time to give his father one for Christmas. He is currently making a batch of 22 with several already sold. He thinks of this as his retirement business in the making.

“It’s possible that somebody has a more obscure business model than making reproductions of 18th century scientific demonstration apparatus. My worst nightmare is success; I’d like this to be something that delights the occasional person and presumably contributes to the education of young people,” admitted Donnelly.

He also sees his purpose as building machines that start conversations and one conversation he would like more people to have is about the inventor of the Orrery, James Ferguson. Born a farm boy, Ferguson was the first popularizer of science, a member of the royal society, and the inventor of many demonstration apparatuses. This incredibly accomplished scientist’s education and upbringing are, “the best illustration of the phrase, ‘It takes a village to raise a child.’”

Donnelly noted, “I regard it as part of my mission in the little booklet that comes with each orrery I sell to tell the story of Ferguson. We’re just custodians of this knowledge and if we don’t push it forward it will be lost.”

Learn more about Donnelly’s work at

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