What in the heck is an Orrery? If you’re looking at the image above we’re sure you’ve already figured it out (kudos to the big brains that knew the word). For those that don’t get it, an Orrery is a mechanical device that represents the movements of planets and moons. We never thought of building one ourselves. After seeing the machining process for what’s shown above we’re not sure if we’re excited, or scared off by all the work that went into it.
You might want to bust out the Chromecast and hit the sofa for this one. There are dozens of YouTube videos showing the build. From cutting sheet stock into round slugs, to making teeth, teeth, teeth, and more teeth it’s not just the gears that go into this one. You’re also going to needs the orbs themselves.
We have fond (perhaps scary) memories of the first time we saw an Orrery as a part of the set in The Dark Crystal.
[Via CNC Cookbook via Make]
26 thoughts on “Machining An Orrery”
I LOVE these things, wish I’d have one of those…
I grew up in Vermont’s “Precision Valley” where gear tooth cutting was high art. My friends worked at “Fellows Gear Shaper” and “Bryant Chucking Grinders” and “Jones & Lampson Comparators” The “hard disk” as we know it today was first made in Vermont’s Precision Valley. Yankee craftsmanship at its finest. Alas it’s all moved offshore.
I really enjoy reading/watching videos about stuff like this.
I was immediately reminded of the Retrotechtacular posts on HaD about naval targeting computers and pocket watches!
Although a lot of our modern gadgets are digital, electronic, etc, there’s still applications where you need mechanical bits to get the job done.
The knowledge of this “old” tech is definitely something that shouldn’t be lost to time, and I’m glad there’s still people who are willing to teach themselves, and to write up their experiences, to further disseminate the information.
I wonder how accurate that movement is. It looks pretty close as far as the Moon goes.
He tells you exactly how accurate it is in his writeup. It’s pretty good!
I wonder how you reset a planet once it gets a tooth too far or too behind. Wish the blue gear was locked so it didn’t keep lurching with each revolution of (I think) the moon
Here’s the page I was remembering:
He tells you exactly how the planets are set in one of the build videos in part 3:
http://www.youtube.com/watch?v=jLC7FKi37SQ (first minute and a half or so),
demonstrates it here:
http://www.youtube.com/watch?v=aGMuu3n2YQk (first minute),
and very well here:
Oh, and nice build!
Those gears are under almost no load, so all of the complex gear math, etc, is not necessary. Gear wear would also not be a major consideration. Point being, it isn’t necessary to extensively fuss over the gear tooth interfaces.
I would cut the gears from flat sheet, on a CNC. Whether from plastic, brass, or aluminum.
Perhaps more interesting would be an Orrery of a planet and it’s many moons. Did you know Uranus has 27 moons? Bonus points for getting all the planets and moons, and even those chunks that they say don’t qualify for moons. Double bonus extra credit for the ability to add new objects to the mechanism as they are discovered.
“Did you know Uranus has 27 moons?”- Yours maybe, not mine! :P
took me a second, lol
A million points for solving the three-body problem, for a clockwork solar system!
Yeah I think it’s pretty impressive even if the orbits are circular instead of elliptical.That said, watching the guy machining the parts is pure maker porn!
Elliptical?! I thought they were epicycles!! :O
Not sure if joking or 2300 years out of date. Though Newton did deal some with epicycles. He was wrong about nearly everything outside of optics and math theory.
Make the thing small enough and the eccentricity is smaller than the tolerances.
Make it big enough and we can just drive over the gears to visit Mars.
Would one use a planetary gearset to make this? Anyone… anyone? I’ll show my self out…
Awesome job, would love to have one of these, I have always found them fascinating.
Good one, I got that transmission…
I do too, I keep thinking all I need to do and acquire to make one as beautiful as this piece, but reality is slowly setting in.
As an amateur astronomer, I can’t help but be impressed by this, even though if I were on the Starship Enterprise coming back home to that solar system I’d be initially confused as to whether that was Earth or that Neptune had somehow taken its place and ask Spock for a confirmation. But then I’m not trying to take anything away from the build, I really admire the effort!
“Pale blue dot”
Wow, now that is craftsmanship, well done!
Oh wow… I desperately want to make something like this. I’ve been wanting to get into gear-cutting for a while now, but those cutters are so damned hard to get and/or expensive. :(
Man, I’d love to make one of these, even just a smaller Sun-to-Mars one, inside a bell jar.
Don’t forget the solar Orrery in Pitch Black !
http://www.youtube.com/watch?v=pSWXlm9I05o (1:23 – 1:30)
Hackaday Concept: Place a small camera where Earth is, allowing you to compare the calculated positions with the real sky.
Bonus points: cameras for all the major planets.
Extra bonus points: Mirrors instead of cameras, in a periscope configuration, for a purely mechanical visualisation.
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