The Antikythera Mechanism Episode 9 - Making The Epicyclic Pin and Slot Gearing

Hi Mario, I have used direct measurement of the CT scans for the dimensions, however Tony Freeth has published some of the math on it (I don't recall which paper). He also discusses the concept in detail as it relates to his theory of the planetary module in his 2012 paper: <a href="http://dlib.nyu.edu/awdl/isaw/isaw-papers/4/" rel="nofollow noopener" target="_blank">http://dlib.nyu.edu/awdl/isaw/isaw-papers/4/</a> - Cheers :)

Clickspring

Hello Chris. I am fascinated with this wonderful project. The more detail I know of the operation of the mechanism that makes it work, the more fascination I feel. So thank you very much for sharing your knowledge. Now, I have a question. Could you tell us how to calculate the measurements of the gears of the pin-and-slot module (diameter, module, distance between centers, etc) in order to simulate the speed of the Moon in its elliptical path? Have you used a mathematical equation for these? Are they based on trial and error? Thank you very much, Mario.

Mario Pérez Domínguez

Yes it will - the two leading theoretical proposals are by Michael Wright 2006 (<a href="https://www.youtube.com/watch?v=IT0gXa1ZrnA&t=2s" rel="nofollow noopener" target="_blank">https://www.youtube.com/watch?v=IT0gXa1ZrnA&t=2s</a>) and Tony Freeth 2012 (<a href="http://dlib.nyu.edu/awdl/isaw/isaw-papers/4/" rel="nofollow noopener" target="_blank">http://dlib.nyu.edu/awdl/isaw/isaw-papers/4/</a>) However neither is entirely consistent with the evidence, and I will address that with my own proposal - Cheers :)

Clickspring

Will your reconstruction include the gearing to model the retrograde motion of the planets? also do you have any good sources on how it was done? Can't seem to find much by myself.

Marius Olsen-Ryum

I missed that Nature article when it was published. Good. I've got a reasonably up to date schematic of the mechanism as a tattoo, not looking forward to the day when I have to modify it with new parts.

Derek Kinsman

Thank you mate - unfortunately the article rather misrepresents the find. Here is one of several press reports released when the find was announced last year that gives a much better take on it: <a href="https://www.nature.com/news/antikythera-shipwreck-yields-statue-pieces-and-mystery-bronze-disc-1.22735." rel="nofollow noopener" target="_blank">https://www.nature.com/news/antikythera-shipwreck-yields-statue-pieces-and-mystery-bronze-disc-1.22735.</a> The artifact is presently assumed by researchers to be a decorative element, un-related to the mechanism. I haven't seen any data released since Oct 4 2017 that would challenge that assumption - Cheers :)

Clickspring

An article about a newly discovered Anyikythera piece showed up today. Thought it might interest you. <a href="https://www.haaretz.com/archaeology/.premium.MAGAZINE-missing-piece-of-antikythera-mechanism-found-on-aegean-seabed-1.6640779" rel="nofollow noopener" target="_blank">https://www.haaretz.com/archaeology/.premium.MAGAZINE-missing-piece-of-antikythera-mechanism-found-on-aegean-seabed-1.6640779</a>

Derek Kinsman

My wife is the same

Jack Caddy

My girlfriend loves watching these videos, she knows and cares nothing about metal shaping or ancient horology but she finds these beautifully produced videos mesmerising along with the narration by Chris. I'm looking at putting together a youtube playlist of my favourites, I'll post it on the Patron community page if I ever get around to it... ;)

Chris Talbot

And this is why any amount of Patron support to Chris is totally worth the money. Great stuff mate!

Chris Talbot

I was wondering about this, great question! I know that brass was/is a very common bearing material, so it must have decent friction properties right off the bat... still, I'm intrigued!

Chris Talbot

That's cool, good mic on your camera!

Chris Talbot

Aah, it's always such a treat to see you do your thing, somehow it's very calming to me. Very nice work so far and it's good to see it take shape at the end.

SilverFox

"ancient Greek merchant's vessel" Sounds familiar. :)

Sean Kirby

If you make a treadle lathe I might lose it!

Wobs

<a href="https://www.iflscience.com/editors-blog/the-worlds-oldest-intact-shipwreck-discovered-in-black-sea/" rel="nofollow noopener" target="_blank">https://www.iflscience.com/editors-blog/the-worlds-oldest-intact-shipwreck-discovered-in-black-sea/</a>

Luke Pettit

Certainly mate, all metric, all brass - Anvil: 50x25x27, square grooves 4x4xfull length, vee grooves approx 45 degrees, approx 2mm deep, full length. Blunt former: 50x22x5, shouldered at top to give approx 12mm to hit, other end is square Rounded former: 50x22x5, same shouldered top, approx 60 degree vee rounded with approx 2mm radius Cheers :)

Clickspring

You wouldn't happen to have info on the shaping tools you made would you?

Steven swenson

At this stage I'm fairly sure it was run dry, more detail in a later video - Cheers :)

Clickspring

Cheers mate :)

Clickspring

And here was me, thinking this build couldn't get any better. Mind blown.

Rene Schickbauer

What do you think was used for lubrication? Or was it run dry?

Marcus Ekner

Cheers mate :)

Clickspring

Not added in post, camera audio :)

Clickspring

Whew! I was worried that I wasn't going to have my "fix" but you came through in great form. Beautiful job!

Scott Clausen

Hi, Chris, thank you for that idea. I found a cheap glass cutting board that I'm going to try, but it is good to know about other options as well. I'm still working on the finer details, like fit and finish for projects. Several things I make don't need it, but others will look a whole lot better with all this great information being shared. Cheers...

Spirit of the Warrior

PS. I love the little "snap" you added in post at 04:54... little touches like that are what make this channel stand out.

Chris Talbot

Hi Nickolas, if you ever have to sand/polish/lap something to a good near-perfectly-flat surface, a conveniently sized piece of normal window glass is about the best cheap option to produce a good result. It's also known as "float glass", you can google it. :)

Chris Talbot

Thanks Chris. Gives a good idea of just how much work is going into this... 3 trial runs for one little part before you were finally happy. Craftsmanship! Looking forward to the next installment mate!

Chris Talbot

Thank you mate, was a real moment for me too for that first test assembly - Plenty of SW prep for that little arbor, but its a classic test and fit part, with no real way to predict exactly how all of the clearances would stack up in all orientations once assembled. 3x (I think?) before final part, with quite a bit of fettling of each iteraton to figure out what was needed - Cheers :)

Clickspring

Watched this a while back but forgot to comment... how unlike me! Really cool to see how the epicyclic "module" came together after the sneak-peek in your update post. Those really are some finicky little parts, and you've done such a neat and precise job of bringing them all together, as usual. I literally let out an "ooooooohhh" when I saw the mechanism turning. :D That multi-shouldered arbor is a particularly lovely bit of work, how many attempts did it take you to get it spot-on? Or did you just spend a lot of time in solidworks before starting to turn the metal?

Chris Talbot

Yes I'm well inside the design now. There is so much there its incredible - Cheers :)

Clickspring

Thank you mate!

Clickspring

Totally awestruck by the mechanism finally coming together. You continue to amaze me with your work, chris!

Benjamin Strauss

Chris, brilliant work as usual. Now that you've reached this point, are you starting to 'feel' (not crazy about that word...!) something of the original maker? I know, from a modern perspective, where most humans never get out and and look at the heavens, it's an almost foreign concept. But it strikes me this ancient craftsman must have felt something like a modern physician prescribing antibiotics in the early days of its 'discovery' (before its abuse in the Western world). A feeling of understanding/awe and being able to put their actual hands on it.

Wes Baker

No, its a fairly ductile material, so assuming normal room temperature, no corrosion etc the risk of cracking is pretty low - Cheers mate :)

Clickspring

Chris, have you ever broken a wheel/gear with a taper pin? I have to remind myself sometimes that you're working with very thin stock and I've gotta think cracks happen every now and then.

Jerry Gepes

Thank you mate, will do!

Clickspring

Ha ha! Thank you mate :)

Clickspring

Right around 4:25 ish... I feel like the tapping of the punch was timed with the music... Or im hearing things and expecting such serendipitous precision from you LoL Either way, seeing the bits come together at the end was pretty amazing. I can't even imagine what its going to be like when its all done! Keep up the great work!

Clifton Ballad

Thank you for the information; that is a brilliant idea! I think I will have to try that in my shop, because it would certainly make cleaning up a lot easier. Cheers...

Spirit of the Warrior

This is just a Wow moment. That was the part I was looking forward to seeing how it was done. I remember reading somewhere (I'm still looking) about the gearing not being perfect so they had to increase the distance between two teeth by introducing a crack. This made the gearing more accurate as to the Moon's position. Did you run into that reference somewhere? I believe it had to do with these particular gears. On a side note, since I am paying you via Patreon, you can no longer consider yourself an Amateur. Not that your work has improved since your earlier videos. Na, nothing like that. All I'm seeing at this point is Craftsman. I'm thinking by the end of this with will be Master Craftsman. And when you reproduce ENIAC out of brass, you'll be off the charts!

Kevin Reardon

Hey Kirk - the bulk of the train is assembled, and then the last assemblies with the pointers are dropped into place pointing where they need to relative to the dial. It will be a bit more complex for the planetarium gearing, because the correct position in each phase must also be established, but it amounts to basically the same process - very fiddly!

Clickspring

Awesome John, I'm so pleased :)

Clickspring

Hello mate - that is a pin rounding tool. A few twists and it puts a quick chamfer on the end of a pin -Cheers :)

Clickspring

I still am interested on how you are going to time the entire mechanism once you are complete, So that all outputs read correctly for day 1 of its life.

Kirk Jensen

I saw the email that this video was posted and everything stopped while I viewed it. Wonderful work. I'll be watching it again this evening.

John S Dilsaver

Thank you Nickolas, so pleased you're enjoying the videos :) Yes I use glass because its a cheap, hard & flat surface that can be dunked in water and other solvents etc - Cheers :)

Clickspring

What's going on at 9:36? Looks like drilling the middle of the peened pin; I just don't know why. Was that in a previous video? (if so, I must have missed it)

Christopher

Hello, Chris, I just have to say that I admire the love and dedication that goes in to each component. Even if it may never be seen, it is still a beautiful piece of work. Your research and dedication to learning and demonstrating some of the old ways that could have been used is remarkable. On a side note, it appears you do some of the sanding on a glass cutting board; is there a particular reason for that? Cheers...

Spirit of the Warrior

So pleased you enjoyed it mate :)

Clickspring

Cheers Ian :)

Clickspring

Thank you mate!

Clickspring

Cheers Tyler :)

Clickspring

Thank you mate :)

Clickspring

Yes its along the lines of your last suggestion Iain, in that essentially it doesn't matter. Its a bit like a clock mechanism; all that really matters is the relationship between B1 and the output pointers, and that relationship is set at assembly. The main solar drive wheel is set to a particular 'day', the majority of the train assembled, and then the last assembly carrying the pointer is dropped into position pointing where it needs to relative to the dial. (In some cases it could also be done by removing an assembly a little further up the train: eg remove the L assembly, orient the Metonic pointer, and then reinsert the L assembly) - Cheers :)

Clickspring

Awesome mate, so pleased :)

Clickspring

Gday Chris, Liked before even watching, beautiful vid and starting to come together really well looks awesome TFS G :)

Graeme Brumfitt

I'm glad you asked - the same question just came into my mind!

David Jenkins

Let’s just hope he answers 😂, otherwise we’ll have to email TOT

Iain Deas

Beat me to it. Was going to ask exactly that question. :)

Sean Kirby

Reckon there might also be a potential market for Patrons who'd like to gift this wonderful video series to older relatives/friends that have an interest in horology/home machine-shop projects, but perhaps aren't really into this "newfangled internet business". That idea aside, a disc-based copy of the series would make a great gift for just about anyone who is into "Maker" stuff, and it could be referred to anywhere there's a TV/DVD player but not necessarily a broadband connection. Could also be a nice way to say "Thanks!" to the more generous Patrons, "your name here" in the DVD credits.

Chris Talbot

Out of curiosity Chris, when you have multiple gears on one shaft or situations like the gears that get peened on a shaft, do you have to take into consideration the orientation or the alignment of the teeth? Or do you just place them however and they all find their mesh when the whole thing starts turning?

Iain Deas

As always. You are a Wizard.

m_tini

Superb!

Jeremy

Could you sell the production to National Geographic or some other outfit?

Gregor Shapiro

Absolutely stunning craftsmanship and video, had to watch and listen a few times to understand how the eccentric mounting provided the anomalistic lunar motion, loved the shot of the peening!

Gregor Shapiro

With a lathe and files - its clear that the technology of the day was very capable, more on the lathe tech in a later video - Cheers :)

Clickspring

Thank you mate, will do :)

Clickspring

Thank you Mike :)

Clickspring

Would certainly look at it if there was enough interest :)

Clickspring

Thank you mate :)

Clickspring

Cheers :)

Clickspring

Cheers :)

Clickspring

Thank you mate :)

Clickspring

I only now realized how small these parts are, seeing your fingers in assembling them, amazing. How do you think they would have made the main arbor with the technology of the time? That's what I find most amazing along with that off axis turning.

Hermann Björgvin

I was watching Ancient Aliens on The History Channel the other day and was amused by all the "they could never have built this all those years ago" hullabaloo (well, except the pyramids, of course; those were obviously built by aliens). There's this odd notion that just because we don't know how they did it, they couldn't possibly have done it. Indeed, it couldn't possibly be because we've lost their techniques to history. Similarly, there's this odd notion that ancient also means incompetent by modern standards. I think this device is proof enough alone that while our ancestors didn't have all our handy tools and technology, that doesn't mean they were stupid and incapable of incredible complexity and ingenuity. I think in a lot of ways our technology might actually be making us lazier/less creative than our "primitive" forefathers. Good stuff, Chris, keep up the great work!

I'm in awe both at the ingenuity of this mechanism and your continued insights and patience regarding its construction.

Mike Michelizzi

Holy crap Chris, you are the man!!

Kirk Jensen

So, when this is all said and done, will you put out a feature-length DVD/Blu-Ray of the whole series? I would love to have such a thing.

jason black

Mind blown....

Unreal.

Daniel Shattuck

Hopefully I'll have a part ten waiting for when when my power to come back

Just some stale toast

That's good to know, keep up the good work, I've been a fan since the third part of the skeleton clock

Just some stale toast

Bravo. Amazing job.

Try Keeping Up

Thank you mate, very much appreciate your support :)

Clickspring

Subliminally embedded while watching no doubt :) Completely agree re the smarter point - to a large degree the limits of this machine were about material science limits more than anything else - Cheers :)

Clickspring

Great video! Loving it!

PseudsPie

Thanks John, much appreciated :)

Clickspring

Thank you mate!

Clickspring

Ha ha! Back to the grind!

Clickspring

you the man, Chris!

Stubbs

Thank you mate!

Clickspring

this patreon is worth every penny

Stubbs

No plans would definitely mean differences, but I am well inside the design now so i think it would be very similar - Cheers :)

Clickspring

Thank you mate, so pleased you enjoyed it :)

Clickspring

Thank you mate - yes certainly, that E arbor took quite a bit of testing to get right, the difference between 'go' and 'no go' on the shoulder dimensions is crazy - Cheers :)

Clickspring

So pleased you enjoyed it mate, best wishes with the clean up I know exactly what you're going through :)

Clickspring

A Dr Who ("The Master's" Head noise no less) cadence of hammer peining happening at 4:27 a coincidence or not? The guys who made this were ficken geniuses. When I was young my dad use to say mankind hasn't really gotten any smarter we just have better access to more information. I am dumb founded at their, and your skill and obvious genius. I might go lick a window in order to comfort myself lol

Luke Pettit

Outstanding work Chris.

OldSaltyPossum

Incredible work!!

Eric Hobbs

Incredible! I already can't wait for the next one!

Derek Meisenhelder

Another incredible video, Chris! Awesome to see how it's coming together! :)

Mathew McGuire

if you were commissioned to build a device with the same capability without any plans to work from, could you do it? would it end up being drastically different or would there be similarities?

Dylan T

You never fail to impress.

Adam Slagle

Not only do you make things look so beautiful, the damn things fit together so well that they *click* when you push them together! Always makes me gasp internally lol. Do you ever stuff anything up and overfile and have to start over?

Stu

Well, a hurricane just blew up everything I know, and I'll have a month without power, but honestly this being uploaded makes me happy

Just some stale toast