Antikythera mechanism

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Re: Antikythera mechanism

Postby minimoa69 » Sun Apr 05, 2015 11:05 pm

Evening all,
I'm getting on quite well with cutting out the gears for phase 2 of the build (which I suppose you could call 'the rest of it'...) and should be finished with them in the next day or two. It's taken a while as there are so many to cut in the main part of the machine - 32 I think - and I had to have 3 attempts at cutting the big 223 tooth gear as I kept getting it wrong. Oh well, it's all good practice I guess. Just a shame that each one was a days work...
The next bit is the good bit though - putting it all together. I really can't wait to actually see it working - I've never actually seen one in the flesh before!

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Re: Antikythera mechanism

Postby minimoa69 » Sun Apr 12, 2015 10:04 pm

I've been beavering away for a few days now with the freshly cut new batch of gears, and just today I've managed to crack the moon anomoly gearing - this little group of four gears slowly rotating on a much larger gear is quite a big deal for those 'in the know'. It's what set the scientific community alight when it was first discovered on the original machine back in the 70's. Is a complicated little set up with 4 gears, all with 50 teeth, that simply drive one another, but via a clever pin and slot mechanism to provide a variable speed output, and two of the gears share a near common pivot point but with different centres... tricky...
'So what does it do?', you may be asking. Well, in a nutshell, it accurately shows the moons natural tendency to apparently speed up and slow down as it orbits the Earth due to its elliptical orbit. Doesn't sound like much, but on a machine that's over 2000 years old, and to do this little trick with a long term accuracy which means that it's predictions of the moons position and phase are correct hundreds of years into the future is, well, nothing short of stunning.
Sorry - starting to get a little over enthusiastic there... won't happen again...
The second photo shows some of the gearing placed in context ready to mark out the support frames that will house everything. The photo shows just over half the remaining gearing, so still quite a bit to go.
More soon I hope.
:-)

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Re: Antikythera mechanism

Postby SkyWatcher17 » Mon May 04, 2015 8:55 pm

That's one of the most amazing things I have ever seen. Thanks for posting. I remember reading about the Antikythera Mechanism when I was very young. It still fascinates me how that level of technological sophistication disappeared when it sank into the Mediterranean.
Sky-Watcher Explorer 130M, EQ5 Deluxe, AZ5 Deluxe, SkyMax 102mm, SkyMax 127mm, Orion/SW ST80s (both modified), Vixen Porta II/Vixen SXG Hal-130, Orion 90mm StarMax , Celestron NexStar Evolution 9.25", TS Optics/GSO: SVD series 150mm, f/6.
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Re: Antikythera mechanism

Postby minimoa69 » Mon May 11, 2015 10:55 pm

Here's a photo of the last dry fit of the first batch of gears before I start cutting the pivot holes for the axles. I'm beginning to work out why there aren't more of these contraptions out there - it's a complicated old beasty...
More soon when I should have some spinning gears to share.

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Re: Antikythera mechanism

Postby dave.b » Thu May 14, 2015 11:04 pm

"Sorry - starting to get a little over enthusiastic there... won't happen again..."

If anything I would appreciate hearing a lot more details about how this machine works. :-) And how you came about the design. And how you making it. :-)

Dave B.
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Re: Antikythera mechanism

Postby minimoa69 » Sun May 31, 2015 12:03 am

Hi Dave,
I really should come back here more often and check for replies.
To answer your question, this machine comes after building around 15 wooden geared orreries, and I guess that building them was really a training program of sorts to give me the skills to tackle this beasty - something that I've wanted to do for the past decade or so. There's no way I could have done this even two or three years ago, I just didn't have the experience back then.
As for the design, well the basic gear trains you can find all over the Internet - it is, at the end of the day, just gears driving gears (with a couple of unusual bits thrown in just to spice things up a bit). So if you can read a basic gear diagram then you are half way there - all the raw information is out there. All you have to do then is cut them out, mount them into a framework of some description, and hey pesto,
one antikythera mechanism! In truth, I guess that there was a good year or so of research before I got anywhere near cutting a component, and even now I'm learning about the mechanism and changing bits as I go along. Some things aren't obvious until you actually try and build one.
If you want to learn more about the original and the research that's gone into it, the Wikipedia article on the machine is now very, very good, have a peak if you get a chance.
in the mean time, here are two films of the latest test fits of two halves of the main gear train before full assembly.
More soon.
:-)
Anrikythera mechanism main gear train part 2.: https://youtu.be/5u4eW5zXXlU
Antikythera mechanism wooden replica: https://youtu.be/2dE5drxJv9I
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Re: Antikythera mechanism

Postby dave.b » Sun May 31, 2015 8:47 pm

As always, it's looking good from those videos.

You really should consider collating all this information into a book.

Best regards
Dave B.
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Re: Antikythera mechanism

Postby minimoa69 » Fri Jun 05, 2015 9:17 am

dave.b wrote:As always, it's looking good from those videos.

You really should consider collating all this information into a book.

Best regards
Dave B.


Thanks Dave, but although I have a lot of notes regarding the build, I'm not entirely sure that the world at large is entirely ready for my literary genius...
Anyhow, attached is the first photo of the machine part way through its first test assembly. This stage is just to prove that everything fits together like planned before I fit all together permanently. It doesn't actually run yet (test assembly only), and there are quite a few gears still to fit, but it gives a good idea of where I'm headed rather than just more random photos of gearing. It's actually starting to look, dare I say it, quite impressive! I just hope that I can get it running...
More later when the rest of it is fitted.
:-)

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Re: Antikythera mechanism

Postby dave.b » Fri Jun 05, 2015 7:01 pm

Dave,
Firstly, let me say wow about that photograph of the assembly in the previous post!

Secondly, you shouldn't be so modest about your writing skills when it comes to the idea of a book. You have written very clearly on this forum, you have obvious technical skill, and judging by the fret work in those side supports some artistic talent too! Moreover, the book's main focus will be the design and construction of the mechanism which is all within your comfort zone of expertise. :-D

Dave B.
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Re: Antikythera mechanism

Postby minimoa69 » Sun Jun 07, 2015 5:23 pm

Thanks for your confidence in me Dave, once I get it working we shall have to see...
Anyhow, it's photo time! Here it is, all gears installed (though still not working yet) with its stand fitted, and, completely coincidentally, now looking every inch like a 1950's space rocket as my daughter was keen to point out to me... and quite a happy coincidence as it turns out.
Next job - get it working!
More soon.
:-)Image
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